Densities of Solvents

Solvent	Density (g/mL)
Acetone	0.79
Benzene	0.88
Chloroform	1.50
Dichloromethane	1.33
Diethyl ether	0.71
Dimethyl sulfoxide	1.09
Ethanol	0.79
Ethyl acetate	0.89
Hexane	0.66
Isopropanol	0.79
Methanol	0.79
Pyridine	0.98
Tetrahydrofuran	0.89
Toluene	0.87
Water	0.998

The Difference between Single and Double Mechanical Seals

If you’ve made the switch from packing to mechanical seals, you understand the positive impact mechanical seals have on your systems. One of the main reasons to switch to mechanical seals is the drastic reduction in leakage, which in the long term, saves maintenance valuable time and money.

Mechanical seals are devices that seal machines between rotating parts (shafts) and stationary parts (pump housing) and are an integral part to the pump. Their main job is to prevent the pumped product from leaking into the environment and are manufactured as single or double seals. What's the difference between the two?

WHAT IS A SINGLE MECHANICAL SEAL?

A single mechanical seal consists of two very flat surfaces that are pressed together by a spring and slide against each other. Between these two surfaces is a fluid film generated by the pumped product. This fluid film prevents the mechanical seal from touching the stationary ring. An absence of this fluid film (dry running of the pump) results in frictional heat and ultimate destruction of the mechanical seal.

Read more about reasons why mechanical seals self-destruct on our blog.

Mechanical seals tend to leak a vapor from the high pressure side to the low pressure side. This fluid lubricates the seal faces and absorbs the heat generated from the associated friction, which crosses the seal faces as a liquid and vaporizes into the atmosphere. So, it's common practice to use a single mechanical seal if the pumped product poses little to no risk to the environment.

WHAT IS A DOUBLE MECHANICAL SEAL?

A double mechanical seal consists of two seals arranged in a series. The inboard, or “primary seal” keeps the product contained within the pump housing. The outboard, or “secondary seal” prevents the flush liquid from leaking into the atmosphere.

Double mechanical seals are offered in two arrangements:

• Back to back
  • Two rotating seal rings are arranged facing away from each other. The lubricating film is generated by the barrier fluid. This arrangement is commonly found in the chemical industry. In case of leakage, the barrier liquid penetrates the product.
• Face to face
  • The spring loaded rotary seal faces are arranged face to face and slide from the opposite direction to one or two stationary seal parts. This is a popular choice for the food industry, particularly for products which tend to stick. In case of leakage, the barrier liquid penetrates the product. If the product is considered “hot”, the barrier liquid acts as a cooling agent for the mechanical seal.

Double mechanical seals are commonly used in the following circumstances:

• If the fluid and its vapors are hazardous to the operator or environment, and MUST be contained
• When aggressive media are used at high pressures or temperatures
• For many polymerizing, sticky media 

Are you still using packing for your pumps? Read about the differences between packing and mechanical seals to see if switching to mechanical seals makes sense for your plant. A qualified engineer will help you decide which type of mechanical seal is best for your application.

Glass-lined reactors for active pharmaceutical ingredient manufacturing

In Pharmaceutical industries, we come across processes handling acids and sticky materials in batch reactors. Most bulk drugs are manufactured in batch wise operations. Acid reactions and crystallization operations were performed in stage wise repeatedly from initials raw materials treatment to final purification of product. Active pharmaceutical ingredient abbreviated as API is the key compound of the drug designed to perform treatment to the health problems. Regulatory bodies like FDA (Food and Drug Administration) strictly advices and inspects the cleaning of the reactors that are used for processing API. Drugs like Nizatidine, Sertraline HCl and Fluconazole stick to the surface of stainless steel reactor even after thorough cleaning with water and methanol their trace are found by conducting the swab test. The glass-lined reactor solves this problem of contamination.

Equipment Description of Batch Type Glass-lined Reactors:

Basic reactor model contains the blue colored glass lining inside its surface. Dome is fitted to the cylindrical vessel by “C” type clamps placing food grade gasket between them and the vessel has an opening at the bottom. The hemispherical dome has provision to fit thermocouple, agitator, dip rod and baffles. Dome and every part exposed to the API are glass lined. Heat transfer to the reactants in the reactor is provide by circulating the heating media like steam through the circular tubes fitted outside the vessel mostly half pipe jacket was used. PTFE lined accessories are used to prevent the stress during the assemble on the nozzles for dip tubes and spargers. Sleeve with PTFE lined are used for mounting the accessories on the doom.

Types of external baffles used to improve the flow pattern:

• Fin baffle
• d-type baffle
• h-type
• Finger baffle
• Beaver-tail baffle

For performing distillation and cleaning operations, these glass-lined reactors also have provision for reflux line, vapour line, nitrogen purge line, and vent line. Some of the merits and demerits of glass-lined reactor are:

Merits	Demerits
Easy and effective cleaning operation between batches Suits for batch distillation Withstands to acidic and ionic solutions Prevent scale formation	Glass fragile nature Difficulty to repair the breakage section Low operating pressure

Research conclusion:

Liquid phase chemical reactors with micro channels in glass-lined reactors:

Mixing of two or more solutions must occur to undergo the chemical reaction in liquid phase which is controlled by the contact pattern. Devices that enhance the rapid mixing are the interest of researchers in the field of diffusion mass transport. The key factors they concentrate in research are

• Micro mixer technique
• Flow maintains by lamina phenomena
• Continuous flow device designing

Glass-lined reactors if fabricated from micro level then batch models can be replaced with continuous model so that active pharmaceutical ingredients can be manufactured continuously.

Mechanical seal problem solved

A centrifugal shear screen mixer had been a source of trouble since its installation in 1996. The main source of trouble appeared to have been associated with failure of the environmental controls of the mechanical seals. Classic signs of failure included heat checking of the seal faces, extruded PTFE “elastomer” wedges and worn drive slots and dogs in the carrier and seal face. Various fixes had been attempted or advised by the mixer manufacturer, the original seal vendor, consultants, and alternative seal manufacturers. These fixes had included modifying the original seal environmental control, from a quench-to-drain seal plan supplying double, component type unbalanced seals, to a pressurised thermo-syphon system. The seals in turn were modified to a silicon carbide/carbon face combination.  A low-pressure alarm had also been installed to detect early pressure failure of the thermo-syphon system. Feed and return lines to the thermo-syphon were also replaced with smooth bore hoses in an attempt to improve the flow-rate and thermo-syphon effect. Some site observations were: The mixer was pressure fed from a constant displacement progressive cavity Mono pump. The PRV of this pump was set to lift at 80psi, the PRV was originally believed set at 30psi. When observed, the product pressure at the mixer showed a gauge reading of 20psi, a product temperature of around 20-30 degree C and the thermo-syphon tank had a temperature of between 50-60 degree C. There was a visible level in its sight glass. No temperature differential had been detected across the feed and return lines of the thermo-syphon system, both legs of the system were at the same temperature as the tank. The barrier pressure in the thermo-syphon tank appeared to be approximately 45psi. After investigating the system and stripping the mixer and seal assemblies down, the conclusions reached were that the pusher seals of the generic type fitted to the mixer (T109/MO1/59U) generated significant amounts of heat (partially due to the seals being hydraulically un-balanced). This was especially when used in a double configuration in a seal chamber with a restricted radial clearance. The silicon carbide/carbon face combination also generated more heat than a ceramic/carbon combination. The spring pressure acting on each seal was found to be around 1.37bar (20psi). This was in addition to the barrier pressure of around 3.1bar (45psi) giving a force acting on each seal face of 30kg (68lb), however the inner seal pressure was eased slightly by the product pressure attempting to lift the inner seal faces. It could be seen that a face combination with a higher coefficient of friction and an increased face loading due to high barrier pressure would generate significant amounts of heat. This heat should in theory, and commonly in practice, have been able to be dissipated by an efficient thermo-syphon system. The thermo-syphon tank appeared to hold around 4-5 litres and as such would probably have heated up fairly quickly. It would follow therefore that the surface area of the tank was also relatively small and would thus radiate less heat than a larger tank. The lack of temperature differential across feed and return lines indicated that no flow was actually taking place, and that heat was travelling up both lines by conduction into the tank. As the feed and return lines had been changed for smooth bore versions and the lines had no horizontal legs, bends or kinks and travelled in a constant vertical manner it was not likely that the lines were restricting the flow. Examination of the ports at the seal chamber showed a tortuous route from the seal chamber to the upper connection, and a tangential lower connection to the seal chamber. It would seem that the reasons for failure were that the operators ignored the low-pressure alarm of the pressurised thermo-syphon tank. This was because there was no remote stop/start at the control room, or any automatic safety trip. At alarm condition an operator would have to make a journey to the machine to switch it off. What the operators did to defeat the alarm was to leave the regulated air supply to the thermo-syphon tank permanently on. Unfortunately what subsequently happened was that the liquid level in the tank dropped through normal use, the mechanical seals then failed due to high face loading and temperature (dry running) and of course the alarm didn’t sound. The first any one knew of a problem was a large leak of sticky black product all over the factory floor. I decided that it was necessary to get back to basics and look at the sealing system from the original specification. I found that a double mechanical seal was specified because it was felt undesirable to have a leak to the floor. It being more preferable to have any leak going into the product, hence the pressurised system. However because of the frequent failures it was obvious that they were putting up with external leakage anyway. Further investigation showed that this specification was purely for aesthetic reasons. The system was designed to have a duty and standby mixer, the standby was available but had never been installed. My recommendations were: To remove the pressurised thermo-syphon system and install a larger capacity atmospheric-pressure thermo-syphon system holding approximately 20 litres. Discard the thermo-syphon pressure alarm as redundant. Manufacture a new mechanical seal chamber to accept a 1.5” modular double mechanical seal. This is hydraulically balanced, and the seal faces will see little more than spring pressure loading. Revise the routing of the feed and return line connections through the seal chamber to improve the flow characteristics Connect the thermo-syphon tank via a float-operated valve to a water supply to enable automatic topping up. Re-set the PRV of the progressive cavity supply pump to 30psi Removing the unbalanced mechanical seals and replacing them with a hydraulically balanced cartridge system removed the source of loading and heat. This enabled the small pressurised thermo-syphon system to be removed and a larger atmospheric pressure tank to be fitted. Heat generation at the seal faces was drastically reduced and the tank temperature has dropped to approximately 30 degree C. Mechanical seals have remained in service for 8 months, previous MTBF being 10 weeks. Operator intervention other than initial start-up and shutdown after batch production is not now required.

Mechanical seal failure

Why do most Mechanical Seals fail
A mechanical seal can either wear out, or fail. To determine which one your seals are doing, look at the wearable face. In most instances this will be the face manufactured from some grade of carbon/ graphite.
Since the seal face is the only sacrificial part of the mechanical seal, a worn out seal is identified as one that has no carbon nose piece left at the time it started to leak. A failed seal is identified by the fact that it has substantial carbon remaining at the time it started to leak.

The above illustrations show the difference between a worn out and a new mechanical seal.
Most consumers experience seal failure rates in excess of 85%, and for the most part these seal failures are easily correctable. Seal failures fall into only two broad categories, either the seal faces opened, or one of the seal components was damaged by contact, heat or corrosion. Whenever we try to troubleshoot any mechanical seal it's wise to remember that only three things are visible to a troubleshooter:

• Evidence of rubbing.
• Evidence of damage including corrosion, physical damage, or discoloration of one of the seal component materials. Most mechanical seals are constructed of three materials:
  • Metal parts
  • A face combination
  • Some rubber like parts (called elastomers)
• The product is attaching to a sliding component causing sticking, or coating on the face causing face separation.

Here are some reasons why a mechanical seal face would open:
The dynamic elastomer is not free to slide or move on the rotating shaft or sleeve.

• The shaft is oversize. A tolerance of + 0.000 - 0.002 inches (+ 0,00 - 0,05 mm) would be typical.
• The shaft finish is too rough. Most seal companies want at least a 32 R.M.S. (0,8 micro meters) surface finish in the area of the dynamic (sliding) elastomer.
• The fluid we are pumping is causing the elastomer to stick to the shaft. The dynamic O-ring can generate a lot of heat if the shaft is not perpendicular to the face of the stuffing box. The rapid movement of the elastomer will generate localized heat causing the following to occur at a faster rate:
  • The product is solidifying (glue and paint will do this)
  • It is crystallizing (sugar syrup and caustic are good examples)
  • It is building a coating on the shaft (petroleum products will form varnish or coke at elevated temperatures, or hard water will form a layer of calcium. etc.)
• Dirt or solids are restricting the elastomer from moving.
• Chemicals added to treat water or impurities in the water can collect on the seal sliding surfaces
• A chemical has attacked the elastomer causing it to swell up and restrict the movement of the seal. In some instances a swollen elastomer has been known to open seal faces while the pump was not running in a standby mode.
• The shaft or sleeve has been hardened and the set screws have slipped. Many sleeves were hard coated to resist packing wear. Stock rooms are full of these sleeves.
• The seal has lost its compression.
  • It was installed with the wrong compression.
  • The impeller was adjusted after the seal was attached to the shaft. This is a very common problem with A.N.S.I. or other back pull out pumps.
  • A temperature change has altered the location of the seal. Remember that each inch of stainless steel shaft will grow one thousandth of an inch for each one hundred degree Fahrenheit rise in temperature or 0.001"/1"/100°F . Metric grows 0,001 mm/1 mm of shaft for each 50°C rise in temperature.
  • The open impeller was adjusted to compensate for normal wear. Typical pump specifications allow the impeller and the casing each to wear as much as 0.125 inch (3 mm) and still be adjusted back to the correct pump efficiency. This is important when you realize that the average mechanical seal has a carbon nose that extends only 0.125 inch (3 mm).
• The springs, spring or bellows are not operating properly.
  • A single spring has been installed backwards allowing the faces to stay in contact while the shaft or sleeve rotates within the dynamic elastomer or end fitting.
  • Excessive misalignment is causing rapid flexing of the spring or bellows causing them to fatigue.
  • The drive lugs have failed and the multiple springs are twisted in their holder.
  • The product has clogged the springs.
  • Many times the outside springs of a dual seal have been painted either at the pump company or as part of a normal maintenance routine.

Something is restricting the free movement of the seal.

• The product is viscous. Remember that some products become more viscous with agitation. These products are called dilatants (cream becomes butter with agitation)
• A recirculation line from the discharge of the pump is aimed at the seal and interfering with its movement.
• A foreign object is in the stuffing box.
• A protruding gasket is touching the movable part of the seal

The shaft is being displaced causing the seal to hit something as it rotates, or to cause the rotating face to run off of the stationary face.

• The pump is operating off of its best efficiency point (B.E.P.) causing the shaft to bend.
• The rotating assembly is out of dynamic balance.
• The shaft is bent.
• There is misalignment between the motor and the pump.
• Pipe strain is twisting the pump stuffing box.
• Heat causes expansion and that always opens the possibility for rubbing or wear.
• Cavitation, slip stick, harmonic vibration, bad bearings or some other form of vibration is causing excessive movement of the shaft.
• The shaft sleeve is not concentric with the shaft causing it to run "off center".
• The pump has been designed with sleeve or babbitted bearings and shaft movement is excessive.

The seal face is being distorted by either temperature or pressure.

• Lapped hard faces are especially sensitive to either changes in temperature or pressure excursions.

The product is vaporizing between the seal faces causing the faces to blow apart.

• If boiler feed water vaporizes it leaves behind all of the chemicals that were added to the water to prevent hardness, to control PH, soften boiler scale etc....
• In cryogenic (cold) applications the vaporizing fluid can freeze any lubricant that might have been placed on the seal faces. This frozen lubricant can damage the carbon/ graphite seal face.

An environmental control has failed. There are many types used with Mechanical Seals, here are a few of the common environmental controls:

• Flushing is used for cooling and to wash away solids.
• Quenching is used for temperature control and vapor removal.
• Barrier fluids are used to keep air away from a fluid and to provide temperature control.
• Cooling/ heating jackets are used to keep products in a liquid state and at the proper temperature.
• A suction recirculation line is installed from the bottom of the stuffing box to the suction side of the pump. This is done to remove stuffing box solids in the pumping fluid and to provide cooling to the seal components.
• A line can be installed from the discharge of the pump to the stuffing box to increase stuffing box pressure whenever you pump a fluid close to its vapor point. It is also wise to install a carbon restriction bushing in the bottom of the stuffing box with a clearance of approximately 0.005" to 0.007" (0,13 mm to 0,018 mm) on the inside diameter.
• Dual seals can be installed to prevent a pressure drop across the inside seal face and to control the temperature at the seal face.

Unbalanced seals can open their lapped faces in vacuum applications.

• Those pumps that run under vacuum include: condensate pumps, heater drain pumps, pumps that lift liquid and any pump that takes its suction from a condenser or evaporator. Remember to use O-ring elastomers in vacuum applications as this shape elastomer will seal either vacuum or pressure.
• The product has built up on one of the seal faces causing the faces to separate. This is a common problem with petroleum products or any product that can build a film on a surface. Since this coating is not dense enough to provide good sealing, it can cause the faces to leak at shutdown.

When a seal face opens it allows solids to penetrate between the lapped surfaces. The solids imbed themselves into the softer carbon/graphite face causing it to act like a grinding wheel. This grinding action will cause severe wear in the hard face. It should be noted that seal face opening accounts for the largest majority of mechanical seal failures.
The second major cause of seal failure is when one of the seal components is attacked by the sealing fluid or a chemical being used to clean or flush the lines. Chemical attack is easy to see:

• The Carbon will appear to have a sponge like appearance
• Plated materials will have their hard coating peel off when the base material is attacked. This same thing happens when you allow rust to penetrate behind automobile paint and you then notice that the paint is peeling off in sheets.
• The elastomer will usually swell up and get soft. When an elastomer shrinks and gets hard it is almost always evidence of excessive heat. Prior to failure caused by excessive heat, most elastomers will take a compression set (the round O-Ring becomes square)
• Metal components will develop pits and an overall dull appearance. The color of the metal is often an indication of the amount of heat it was subjected to:

FAHRENHEIT	COLOR OF THE METAL	CENTIGRADE
700 - 800	Straw Yellow	370 - 425
900 - 1000	Brown	480 - 540
1100 - 1200	Blue	600 -650
> 1200	Black	> 650

Here are a few things to consider when you suspect corrosion is the problem :
The corrosion rate of almost all chemicals doubles with each 18 degree Fahrenheit (10 C.) rise in temperature.

• Be sure to vent vertical pumps. Air trapped in the stuffing box is a good insulator.
• See if the operator is running the pump with a restricted discharge. In addition to deflecting the shaft it can cause a severe heat rise in the pump. The control valve may be stuck in the throttled position.
• Try to use a recirculating line from the bottom of the stuffing box to the suction side of the pump. This is practical in almost any application other than when we are pumping a product close to its vapor point and there would be a danger of vaporizing the product in the stuffing box.
• When ever possible bore out the packing stuffing box or install a large seal chamber in place of the packing stuffing box. This extra room will allow centrifugal force to centrifuge and clean the fluid in the seal chamber as well as provide extra cooling in the seal area.
• It is normal to dead end the fluid in the stuffing box when a cooling or heating jacket is being used. If a recirculation line is installed in the stuffing box along with the cooling jacket, the jacket will become inoperative because the circulating hot fluid will not be in the stuffing box long enough to be cooled by the jacket.
• Be sure to check that the cooling jacket is functioning. A layer of calcium inside the jacket, can just about stop heat transfer. If the water is too hard in your area, consider condensate as an alternative cooling fluid.
• More than one stuffing box jacket has frozen in cold weather, be sure to use non freezing cooling fluids at lower temperatures
• If a convection tank is being used with dual seals make sure it is operating. Every design has limits, make sure you are not exceeding them. Also check that the fluid is flowing from the top of the stuffing box to the convection tank and returning to the bottom of the stuffing box. I have seen many of these applications running backwards.
• Use only balanced seals. They generate less heat than unbalanced seals.
• If there is a bypass line installed from the discharge piping to the suction side of the pump, it may be heating up the incoming fluid.
• Check to see if the cooling jacket has been isolated and drained. This often occurs when a metal bellows seal is used in hot oil applications. An empty cooling jacket will act as an insulation to the stuffing box fluid.
• Remember that the cooling jacket is also there to cool down the shaft and protect the bearings. Do not disconnect it.

When you look for corrosion be sure to check out any cleaners or solvents that are used to flush out the system or clean the lines. Many grades of Viton® can be attacked by cleaning the lines with steam or caustic. It is important to identify all of the materials used in the seal components.

• Carbon fillers can be attacked by heat and chemicals
• Plated materials can crack due to differential expansion.
• Stainless Steel springs can break due to Chloride Stress Corrosion.
• Hardened set screws can corrode and vibrate loose.
• Some elastomers can be attacked by steam. Be careful of using petroleum grease on elastomers as some compounds can be attacked by any petroleum product.

Some hard coatings have very little flexibility and will crack with a small differential temperature. Be careful of tungsten carbide with a cobalt binder; nickel binder would be a much better choice.

AUTOMATIC DAM GATE CONTROL SYSTEM WITH CAUTION ALARM USING ARM7

Water level in a dam needs to be maintained effectively to avoid complications. This is generally performed manually which requires full time supervision by the operators & have fairly large staff complements. Moreover, the quantity of water released is hardly ever correct resulting in wastage of water & it is impossible for a man to precisely control the gates without the knowledge of exact water level and water inflow rate. The main objective of this project is to develop a mechatronics based system, which will detect the level of water and estimate the water inflow rate in a dam and thereby control the movement of gates automatically in a real-time basis which offers more flexibility. This system consists of a set of sensors connected to a stepper motor through an 8-bit microcontroller. This microcontroller operates the H-Bridge which in turn control the operation of the DC motor i.e. switches on the DC moving it in a clock wise direction. The water level and rate of inflow is detected based on the feedback from the sensors used. Based on this data, the level of dam gate can be automatically controlled using a DC motor. The LPC2148 are based on a 16/32 bit ARM7TDMI-S™ CPU with real-time emulation and embedded trace support, together with 128/512 kilobytes of embedded high speed flash memory. A 128-bit wide memory interface and unique accelerator architecture enable 32-bit code execution at maximum clock rate. For critical code size applications, the alternative 16-bit Thumb Mode reduces code by more than 30% with minimal performance penalty. With their compact 64 pin package, low power consumption, various 32-bit timers, 4- channel 10-bit ADC, USB PORT,PWM channels and 46 GPIO lines with up to 9 external interrupt pins these microcontrollers are particularly suitable for industrial control, medical systems, access control and point-of-sale. With a wide range of serial communications interfaces, they are also very well suited for communication gateways, protocol converters and embedded soft modems as well as many other general-purpose applications. This project uses two power supplies, one is regulated 5V for modules and other one is 3.3V for LPC2148. 7805 three terminal voltage regulator is used for voltage regulation. Bridge type full wave rectifier is used to rectify the ac out put of secondary of 230/12V step down transformer.

Greek Alphabet

Letter Name	Capital	Lowercase	Notes on common usage
alpha	Α	α	α = alpha particle/radiation (24α) or a type of protein structure (α helix)
beta	Β	β	β = beta particle/radiation (–10β) or positron (+10β), a type of protein structure (β sheet), or a type of oxidation (β-oxidation).
gamma	Γ	γ	γ = gamma radiation (00γ)
delta	Δ	δ	Δ = a change;  δ+ or  δ– = a partial charge
epsilon	Ε	ε	ε = molar absorptivity
zeta	Ζ	ζ
eta	Η	η
theta	Θ	θ	θ = an angle
iota	Ι	ι
kappa	Κ	κ
lambda	Λ	λ	λ = wavelength of light
mu	Μ	μ	μ = micro (unit prefix), dipole moment, or population mean
nu	Ν	ν	ν = frequency of light
xi	Ξ	ξ
omicron	Ο	ο
pi	Π	π	Π = osmotic pressure;  π = a type of bond or orbital
rho	Ρ	ρ	ρ = density
sigma	Σ	σ	Σ = summation;  σ = a type of bond/orbital or standard deviation
tau	Τ	τ
upsilon	Υ	υ
phi	Φ	φ	Φ = work function
chi	Χ	χ	Χ or χ = mole fraction or electronegativity
psi	Ψ	ψ	ψ = wave function
omega	Ω	ω	Ω = ohm (unit of resistance); ω = double bond position in a fatty acid (ω-6 fatty acid)

Densities of Pure Metals

Element	Symbol	Density g/cm3
Actinium	Ac	10
Aluminum	Al	2.70
Antimony	Sb	6.68
Barium	Ba	3.62
Beryllium	Be	1.85
Bismuth	Bi	9.79
Cadmium	Cd	8.69
Calcium	Ca	1.54
Cerium	Ce	6.77
Cesium	Cs	1.93
Chromium	Cr	7.15
Cobalt	Co	8.86
Copper	Cu	8.96
Dysprosium	Dy	8.55
Erbium	Er	9.07
Europium	Eu	5.24
Gadolinium	Gd	7.90
Gallium	Ga	5.91
Gold	Au	19.3
Hafnium	Hf	13.3
Holmium	Ho	8.80
Indium	In	7.31
Iridium	Ir	22.5
Iron	Fe	7.87
Lanthanum	La	6.15
Lead	Pb	11.3
Lithium	Li	0.53
Lutetium	Lu	9.84
Magnesium	Mg	1.74
Manganese	Mn	7.3
Mercury	Hg	13.53
Molybdenum	Mo	10.2
Neodymium	Nd	7.01
Neptunium	Np	20.2
Nickel	Ni	8.90
Niobium	Nb	8.57
Osmium	Os	22.59
Palladium	Pd	12.0
Platinum	Pt	21.5
Plutonium	Pu	19.7
Polonium	Po	9.20
Potassium	K	0.89
Praseodymium	Pr	6.77
Promethium	Pm	7.26
Protactinium	Pa	15.4
Radium	Ra	5
Rhenium	Re	20.8
Rhodium	Rh	12.4
Rubidium	Rb	1.53
Ruthenium	Ru	12.1
Samarium	Sm	7.52
Scandium	Sc	2.99
Silver	Ag	10.5
Sodium	Na	0.97
Strontium	Sr	2.64
Tantalum	Ta	16.4
Technetium	Tc	11
Terbium	Tb	8.23
Thallium	Tl	11.8
Thorium	Th	11.7
Thulium	Tm	9.32
Tin	Sn	7.26
Titanium	Ti	4.51
Tungsten	W	19.3
Uranium	U	19.1
Vanadium	V	6.0
Ytterbium	Yb	6.90
Yttrium	Y	4.47
Zinc	Zn	7.14
Zirconium	Zr	6.52

List of dams and reservoirs in Telangana

List of dams and reservoirs only

#	Name & Place	Constructed Year	Capacity (in TMC)	Main purpose	Notes
1	Nizam Sagar, Nizamabad	1931		Drinking water for Nizamabad, Hyderabad, Hydroelectric and Irrigation	Oldest dam in Telangana State
2	Nagarjuna Sagar Dam, Nalgonda & Guntur	1967		Drinking water, Hydroelectric and Irrigation
2a	Nagarjuna Sagar tail pond, Nalgonda & Guntur			Hydroelectric
3	Singur Dam, Medak	1989		Drinking water for Hyderabad, Hydroelectric and Irrigation
4	Sriram Sagar, Nizamabad	1977		Drinking water, Hydroelectric and Irrigation
5	Lower Manair Dam, Karimnagar	1985		Drinking Water for Karimangar, Warangal and Irrigation
6	Upper Manair Dam, Karimnagar	1985		Drinking Water and Irrigation
7	Kadam Reservoir, Adilabad	1958		Water for Irrigation
8	Yellampalli, Karimnagar			Drinking Water and Irrigation
9	Srisailam Dam, Kurnool & Mahbubnagar	1984		Drinking water, Hydroelectric and Irrigation
9a	Srisailam tail pond, Kurnool & Mahbubnagar	u/c		Hydroelectric
10	Jurala Project, Mahbubnagar	1995		Hydroelectric and Irrigation
11	Pulichinthala Project, Guntur & Nalgonda			Hydroelectric and Irrigation
12	Sri Komaram Bheem Project, Adilabad	2011		Water for Drinking and Irrigation
13	Ramagundam Dam, Karimnagar	NA		Water for NTPC
14	Lower Jurala HEP, Mahabubnagar			Hydroelectric Power
15	Rajolibanda Dam	1956		Water for Irrigation
16	Dummugudem Lift Irrigation Scheme, Khammam			Water for Irrigation
17	Dindi Reservoir
18	Vattivagu Reservoir, Adilabad				Medium Irrigation
19	Osman Sagar Reservoir
20	Himayath Sagar
21	Musi Reservoir
22	Pranahita Chevella
24	Koilsagar
25	Icchampally Project, Karimnagar & Maharashtra
26	Swarna Reservoir, Adilabad				Medium Irrigation
27	Mathadivagu Reservoir
28	SRSP Project Dam
30	Sathnala Dam, Adilabad
32	Shankara Samudram Balancing Reservoir
33	Alimineti Madhava Reddy Project
34	Udaya Samudram Balancing Reservoir
35	Peddadevulapally Balancing Reservoir
36	Ramanpad reservoir
36	Gundrevula reservoir, Mahaboobnagar and Kurnool
36	Singotam reservoir
37	Jonnalaboguda reservoir
38	Pulkurthy Reservoir
39	Salivagu Reservoir
40	Nashkal Reservoir
41	Palakurthy Reservoir
42	Nawabpet Reservoir
43	Tapaspalli Reservoir
44	Pocharam Dam Reservoir
46	Manjeera Reservoir
47	Mylaram Reservoir
48	Devadula project			lift irrigation
49	Chakunta Reservoir
50	Pakhala Reservoir
51	Chalivagu Reservoir
52	Narsingapur Reservoir
53	Bheemghanpur Reservoir
54	Rangaiah-Yerraiah Reservoir
55	Wyra Reservoir
56	Kinnerasani Reservoir
57	Palair Reservoir
57	Kanthapally Barrage
58	Shanigaram Reservoir
59	Thotapally Reservoir
60	Alisagar Reservoir, Nizamabad	1931
61	Alisagar Lift Irrigation Scheme, Nizamabad	2002		Irrigation
62	Lower Penganga River Irrigation Project Maharashtra (Yavatmal and Chandrapur districts) and Telangana (Adilabad)	1997		Drinking Water and Irrigation.	Godavari water tribunal award in 1975. Granted by the State Governments of MA (CM Shiv Manohar Joshi) and AP (CM Naidu) in 1997. [2] Ongoing project.
63	Lendi, Nizamabad and Maharashtra
64	Sadarmat, Adilabad
65	Pedavagu, Adilabad
66	Neelwai, Adilabad
67	Ralevagu, Adilabad
68	Gollavagu, Adilabad
69	Suddavagu, Adilabad
70	Chelmelavagu Project (NTR Sagar), Adilabad
71	PP Rao Project, Adilabad

Welding Codes and How They're Used

Almost all design, welding, fabrication, material, repair, testing, and inspection requirements are covered under three main governing organizations. Even the Department of Defense (DOD) has either adopted many of these codes, or used them as a basis to develop their own codes known as Mil-Specs. These codes are recognized by the American National Standards Institute (ANSI). The following list of codes just barely "scratches the surface" of all existing codes and code organizations. These are the most common codes being used, but there are many others. Many complex jobs fall under multiple codes. These main organizations are the American Welding Society (AWS), the American Society of Mechanical Engineers (ASME), and the American Petroleum Institute (API). All of these organizations have multiple specific codes for various types of construction, processes, and/or materials. Design specifications and approved materials are included in these codes. What I am about to list is only the major codes from these organizations that control metal construction with a brief overview and is not a comprehensive list of every single code that these organizations have available. This information is taken from the latest codes that are available to me and not necessarily the latest editions of these codes. If you need a comprehensive up to date list of any or all of their codes, then you should visit the respective organizations. Think you just landed a contract that doesn't fall under a code? Think again-and read on!


American Welding Society ·

AWS D1.1 This code contains the requirements for fabricating and erecting welded steel structures. This code applies to steels with a thickness of 1/8 inch (3.2mm) or more. When this code is specified in a contract, most of the provisions are mandatory. Optional provisions and examples are shown in an annex included within this code. ·

AWS D1.2 This is the Structural Welding Code-Aluminum. The welding requirements are applicable to any type of welded aluminum alloy structure. This code is appropriate for use in fabrication of supporting structures and appurtenances. It is not intended to supplant codes developed for use in specialized fabrication such as the ASME Boiler and Pressure Vessel Code, aerospace codes, or military codes. ·

AWS D1.3 This is the Structural Welding Code-Sheet Steel. This code covers the arc welding of structural steel sheet/strip steels including cold formed members which are equal to or less than 3/16 inch (.188 in./4.8mm) in nominal thickness. Three weld types unique to sheet steel, arc spot, arc seam, and arc plug welds are included in this code. ·

AWS D1.4 This is the Structural Welding Code-Reinforcing Steel. This code shall apply to the welding of reinforcing steel to reinforcing steel and of reinforcing steel to carbon or low-alloy structural steel. This code shall be used in conjunction with the prescribed general building code specifications and is applicable to all welding of reinforcing steel using the processes listed in Section 1.4, and performed as a part of reinforced concrete construction. When reinforcing steel is welded to structural steel, the provisions of AWS D1.1 shall apply to the structural steel component. ·

AWS D1.5 This is the Bridge Welding Code. This code covers welding fabrication requirements applicable to welded highway bridges. It is to be used in conjunction with the AASHTO Standard Specification for Highway Bridges or the AASHTO LRFD Bridge Design Specifications. This code is not intended to be used for the following: steels with a minimum specified yield strength greater than 690 MPa (100ksi), pressure vessels or pressure piping, base metals other than carbon or low alloy steels, or structures composed of structural tubing.
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AWS D1.6 Structural Welding Code-Stainless Steel. This code covers welding requirements applicable to stainless steel weldments subject to design stress. It shall be used in conjunction with any complementary code or specification for the design or construction of stainless steel weldments. ·

AWS D3.5-93R Guide for Steel Hull Welding. This guide is referenced in many contract specifications for building vessels from barges to tugboats. ·

AWS D3.6M Specification for Under-Water Welding. ·

AWS D3.7 Guide for Aluminum Hull Welding. Similar to the Steel Hull Welding Guide, but with a special emphasis on the unique properties of aluminum. ·

AWS D8.8-97 Specification for Automotive and Light Truck Weld Quality: Arc Welding. ·

AWS D14.1 Specification for Welding Earth Moving and Construction Equipment. Applies to all structural welds used in the manufacture of earthmoving and construction equipment. This specification reflects the welding practices employed by manufacturers within the industry and incorporates various methods which have been proven successful by individual manufacturers. ·

AWS D14.5 Specification for Welding Presses and Press Components. The purpose of this specification is to establish minimum acceptable requirements for weld joint design and the fabrication by welding of presses and press components, and is not intended to apply to material feed mechanisms and tooling. It shall also apply to the modification or repair by welding of new or existing presses or press components.

American Society of Mechanical Engineers ·

ASME Section I Requirements for Power boilers. Part PW lists the Requirements for Boilers Fabricated By Welding. The rules in Part PW are applicable to boilers and component parts thereof, including piping constructed under the provisions of this Section that are fabricated by welding and shall be used in conjunction with the general requirements of Part PG as well as with the specific requirements in the applicable Parts of this Section that pertain to the type of boiler under consideration. ·

ASME Section II Material Specifications-4 Subparts(A,B,C,D). Subpart A-Ferrous Material Specifications. Subpart B-Non-Ferrous Material Specifications-Materials. Subpart C-Specifications for Welding Rods, Electrodes, and Filler Metals. Subpart D- Properties-divided into three subparts- 1 Stress Tables. 2 Physical Properties Tables. 3 Charts and Tables for Determining Shell Thickness of Components Under External Pressure. ·

ASME Section III Nuclear-There are Three Subdivisions- Division 1-Rules For Construction of Nuclear Facility Components. Subsection NB lists Class 1 Components. Subsection NC lists Class 2 Components. Subsection ND lists Class 3 Components. Subsection NE lists Class MC Components. Subsection NF covers Supports. Subsection NG deals with Core Support Structures. Subsection NH covers Class 1 Components in Elevated Temperature Service. Division 2-Code For Concrete Reactor Vessels and Containment. Division 3-Containment Systems for Storage and Transport Packaging of Spent Nuclear Fuel and High Level Radioactive Material and Waste. ·

ASME Section IV Rules For Construction of Heating Boilers. The rules to Part HG apply to steam heating boilers, hot water heating boilers, hot water supply boilers, and appurtenances thereto. They shall be used in conjunction with the specific requirements of Parts HF and HC whichever is applicable. The forward provides the basis for these rules. Part HG is not intended to apply to potable water heaters except as provided for in Part HLW. ·

ASME Section V Non-Destructive Examination. Unless otherwise specified by the referencing Code Section, or other referencing documents, this Section of the Code contains requirements and methods for nondestructive examination which are Code requirements to the extent they are specifically referenced and required by other Code Sections. These nondestructive examination methods are intended to detect surface and internal discontinuities in materials, welds, and fabricated parts and components. They include radiographic examination, ultrasonic examination, liquid penetrant examination, magnetic particle examination, eddy current examination, visual examination, leak testing, and acoustic emission examination. ·

ASME Section VI Recommended Rules For the Care and Operation of Heating Boilers. This is divided into nine subsections. 1-General, covers scope and terminology. 2-Types of Boilers. 3-Accessories and Installation. 4-Fuels. 5-Fuel Burning Equipment and Fuel Burning Controls. 6-Boiler Room Facilities. 7-Operation, Maintenance, and Repair-Steam Boilers. 8-Operation, Maintenance, and Repair-Hot Water Boilers and Hot Water Heating Boilers. 9-Water Treatment ·

ASME Section VII Recommended Guidelines for the Care of Power Boilers ·

ASME Section VIII Pressure Vessel and Tank Code. This is divided into three sub-divisions. Division 1-Subsection A is general pressure vessel information. Subsection B covers the Requirements Pertaining to Methods of Fabrication of Pressure Vessels. Subsection C lists the Requirements Pertaining to Classes of Materials. Division 2 covers Alternative Rules for Construction of Pressure Vessels. Division 3 lists Alternative Rules for Construction of High Pressure Boilers. ·

ASME Section IX Welding and Brazing Qualifications. This section covers the requirements for Weld Procedure Specifications (WPS), Procedure Qualification Records (PQR), and certification requirements for tackers, welders, welding operators, and brazing personnel. ·

ASME Section X Fiber-Reinforced Plastic Pressure Vessels. ·

ASME Section XI Rules for In-service Inspection of Nuclear Power Plant Components. ·

ASME B31.1 Power Piping-This Code prescribes requirements for the design, materials, fabrication, erection, test, and inspection of power and auxiliary service piping systems for electrical generation stations, industrial and institutional plants, central and district heating plants, and district heating systems, except as limited by para. 100.1.3. These systems are not limited by plant or property lines unless they are specifically limited by para. 100.1. Piping as used in this Code includes pipe, flanges, bolting, gaskets, valves, relief devices, fittings, and the pressure containing portions of other piping components. It also includes hangers and supports and other equipment items necessary to prevent overstressing the pressure containing components. The users of this Code are advised that in some areas legislation may establish governmental jurisdiction over the subject matter covered in this Code. However, any such legal requirement shall not relieve the owner of his inspection responsibilities specified in para. 136.1. ·

ASME B31.2 Fuel Gas Piping-Material, This Code covers the design, fabrication, installation, and testing of piping systems for fuel gases such as natural gas, manufactured gas, liquefied petroleum gas-air mixtures above the upper combustible limit, liquefied petroleum gas in the gaseous phase, or a mixture of these gases. Included within the scope of this Code are fuel gas piping systems both in buildings and between buildings, form the outlet of the consumer's meter set assembly (or point of delivery) to and including the first pressure containing valve upstream of the gas utilization device. Piping systems within the scope of this Code include all components such as pipe, valves, fittings, flanges (except inlet and outlet flanges that are a part of equipment or apparatus described in para. 200.1.4), bolting and gaskets. Also included are the pressure containing parts of other components such as expansion joints, strainer and metering devices, and piping supporting fixtures and structural attachments.
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ASME B31.3 Process Piping- Rules for the Process Piping Code have been developed considering piping typically found in chemical, petroleum refineries, pharmaceutical, textile, paper, semiconductor, and cryogenic plants; and related processing plants and terminals. This Code prescribes requirements for materials and components, design, fabrication, erection, assembly, examination, inspection, and testing of piping. this Code applies to all fluids, including: raw, intermediate, and finished chemicals; petroleum products; gas, steam, air, and water; fluidized solids; refrigerants; and cryogenic fluids. ·

ASME B31.4 Liquid Transportation Systems for Hydrocarbons, Liquid Petroleum Gas, Anhydrous Ammonia, and Alcohol. This Code prescribes requirements for the design, materials, construction, assembly, inspection, and testing of piping transporting liquids such as crude oil, condensate, natural gasoline, natural gas liquids, liquefied petroleum gas, carbon dioxide, liquid alcohol, liquid anhydrous ammonia, and liquid petroleum products between producers' lease facilities, tank farms, natural gas processing plants, refineries, stations, ammonia plants, terminals (marine, rail, truck), and other delivery and receiving points. Piping consists of pipe, flanges, bolting, gaskets, valves, relief devices, fittings, and the pressure containing parts of other piping components. It also includes hangers and supports, and other equipment items necessary to prevent overstressing the pressure containing parts. ·

ASME B31.5 Piping Refrigeration-This Code prescribes requirements for the materials, design, fabrication, assembly, erection, test, and inspection of refrigerant and secondary coolant piping for temperatures as low as -320°F except as specifically excluded. ·

ASME B31.8 Gas Transmission and Distribution-This code covers the design, fabrication, installation, inspection, testing and safety aspects of operation and maintenance of gas transmission and distribution systems, including gas pipelines, gas compressor stations, gas metering and regulation stations, gas mains, and service lines up to the outlet of the customer's meter set assembly. Included within this Code are gas transmission and gathering pipelines, including appurtenances, that are installed offshore for the purpose of transporting gas from production facilities to onshore locations. Much more is also covered in this code. ·

ASME B31.9 Building Services Piping-This Code Section has rules for the piping in industrial, institutional, commercial and public buildings, and multi-unit residences which does not require the range of sizes, pressures, and temperatures covered in B31.1. ·

ASME B31.11 Slurry Transportation Piping Systems-This code prescribes minimum requirements for the design, materials, construction, assembly, inspection, testing, operation, and maintenance of piping transporting aqueous slurries of non-hazardous materials, such as coal, mineral ore, concentrates, and other solid material, between a slurry processing plant or terminal, and a receiving plant or terminal.


American Petroleum Institute ·

API 570 Piping Inspection Code- This code covers the inspection, repair, alteration, and re-rating of in-service piping systems. API 570 was developed for the petroleum refining and chemical process industries but may be used, where practical, for any piping system. It is intended for use by organizations that maintain or have access to an authorized inspection agency, a repair organization, and technically qualified piping engineers, inspectors, and examiners, all as defined in Section 3.
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API 620 This code lists the requirements for Design and Construction of Large, Welded, Low-Pressure Tanks. This code applies to carbon steel above ground, including flat bottom tanks, that have a single vertical axis of revolution. The tanks described in this standard are designed for metal temperatures not greater than 250°F and with pressures in their gas or vapor spaces not more than 15 psi. ·

API 650 Welded Steel Tanks for Oil Storage. This standard covers material, design, fabrication, erection, and testing requirements for vertical, cylindrical, aboveground, closed and open-top, welded steel storage tanks in various sizes and capacities for internal pressures approximating atmospheric pressure (internal pressure not exceeding the weight of the roof plates), but a higher internal pressure is permitted when additional requirements are met. This standard applies only to tanks whose entire bottom is uniformly supported and to tanks in non-refrigerated service that have a maximum operating temperature of 90°C (200°F). ·

API 653 Tank Inspection, Repair, Alteration, and Reconstruction. This standard covers carbon and low alloy steel tanks built to API Standard 650 and its predecessor API Specification 12C. API 653 provides minimum requirements for maintaining the integrity of welded or riveted, atmospheric pressure, aboveground storage tanks after they have been placed in service. It covers the maintenance inspection, repair, alteration, relocation, and reconstruction of such tanks. The scope of this publication is limited to the tank foundation, bottom, shell, structure, roof, attached appurtenances, and nozzles to the face of the first flange, first threaded joint, or first welding-end connection. This standard employs the principles of API 650; however, storage tank owner/operators may apply this standard to any steel tank constructed in accordance with a tank specification. ·

API 1104 Welding of Pipelines and Related Facilities. This standard covers the gas and arc welding of butt, fillet, and socket welds in carbon and low-alloy steel piping used in the compression, pumping, and transmission of crude petroleum, petroleum products, fuel gases, carbon dioxide, and nitrogen, and where applicable, covers welding on distribution systems. It applies to both new construction and in-service welding. The welding may be done by a shielded metal-arc welding, submerged arc welding, gas tungsten-arc welding, gas metal-arc welding, flux-cored arc welding, plasma arc welding, oxyacetylene welding, or flash butt welding process or by a combination of these processes using a manual, semi-automatic, or automatic welding technique or a combination of these techniques, The welds may be produced by position or roll welding or by a combination of position and roll welding. This standard also covers the procedures for radiographic, magnetic particle, liquid penetrant, and ultrasonic testing as well as the acceptance standards to be applied to production welds tested to destruction or inspected by radiographic, magnetic particle, liquid penetrant, ultrasonic, and visual testing methods.