Diaphragm Compressors for Gas Processing Applications
PDC Machines has been manufacturing diaphragm compressors since 1977. With decades of
experience in diaphragm compressor technology, we have partnered with companies and
government agencies worldwide to provide them with the optimum solution to satisfy
their gas compression needs. PDC has developed an extensive line of basic diaphragm
compressors and fully automated turnkey diaphragm compressor systems with installations
located around the globe.
Two stage diaphragm compressor for recirculating hydrogen gas. This reciprocating diaphragm compressor meets plant codes and
standards. The scope of supply is a turnkey system including inlet and outlet pulsation dampners, pressure and temperature
transmitters for all stages, segregated junction boxes, etc.. 100% Welded and Radiographed Process Piping & Vessels.
Compressors for cylinder filling and transfilling applications:
If you are not currently using a diaphragm compressor, chances are you are sending tube trailers back with non-refundable levels of unused gas. Or perhaps you are filling cylinders partially while waiting for the next trailer. In either case, you are losing time, money, or both.
But if you were using a PDC diaphragm compressor, you'd be able to draw your gas sources down to a minimum return level and enjoy two benefits. You'd avoid being charged for any unused gas, and at the same time you'd be completely filling your cylinders and lowering your fill cycle time. Also, having a PDC diaphragm compressor at your site gives you the ability to top up your ground storage during off peak times and allows you to cascade fill your cylinders during peak fill times. This lowers your fill cycle time and saves you time and money.
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If you are moving gases from tube trailers or gas generators, or compressing flash off from liquid storage, PDC diaphragm compressors are the ideal choice. Built to last and designed for reliability, our transfilling and cylinder filling diaphragm compressors are in use worldwide supporting the transfilling and cylinder filling operations of all of the major gas producers, distributors and supply houses. From 99.999% helium to welding gas mixes, PDC's diaphragm compressors are the best choice for high purity cylinder filling. The triple diaphragm design guarantees that the process gas will not be contaminated nor will it be vented to the atmosphere due to blow-by entering the crankcase. This means that high purity gas will remain high purity. If you're transfilling hazardous, reactive, toxic, or pyrophoric gases such as monosilane (SiH4), nitrogen trifluoride (NF3), silicon tetrafluoride (SiF4), oxygen (O2), fluorine (F2), or any other industrial or specialty gas, a PDC diaphragm compressor will allow you to do it safely, cleanly and reliably. Whether you are transfilling from tube trailers, cylinder filling for resale, or bottle filling for lab use, a PDC diaphragm compressor is the right tool for the job.
Check our transfill brochure to learn more about the features, benefits and advantages available when you use a PDC compressor for your transfilling and cylinder filling requirements.
We have been privileged to work with many gas producers, chemical and petrochemical companies
around the world. Our clients include 3M, Air Liquide, Airgas, Air Products and Chemicals,
British Oxygen Co/Linde, Bristol Myers Squibb, China Petroleum Corp. ChevronTexaco, Conoco
Phillips, E. I. Dupont, Emirates Industrial Gases Co., ExxonMobil, Fiba Technologies, Foster
Wheeler, General Electric Co; Harris Industrial Gases, Imperial Oil, Korea Specialty Gases,
Kyodo Oxygen, Lockheed Martin, Mead Johnson, Nippon Sanso, Petrobras, Petronas, Phillips
Petroleum, Polish Oil & Gas Company, Praxair, Saudi Arabian Basic Industries, Saudi Electricity
Company, Shell Chemical Company, Stone and Webster, Teledyne Energy Systems, TRW Systems, and many, many more.
Two-stage diaphragm hydrogen compressor fully automated, with auto unloading system, auto-recycle, inter-stage and after coolers.
Meeting NEC Class 1, Division II, Groups B,C,D. This diaphragm compressor is Ideal for filling cylinders and trans-filling from tube
trailers.
Two diaphragm compressors for carbon monoxide service mounted on one common frame. Instrumentation includes transmitters. Suction and
discharge pulsation dampners, isolation valves, winterization package for cold climates. Built to comply with plant standards.
Chevron Texaco Sour diaphragm gas compressor with close loop water cooling system
and crank-case heater and heat traced piping for cold tempreature. Diaphragm Compressor is
designed to plant specifications.
A single stage diaphragm compressor for hydrocarbon gas mixture. Boosting pressures up to 500 psi (34 barg), flow rate 1,600 Nm3/hr
and power is 60 hp (45 Kw). This compressor was installed in the Middle East and meets European codes and standards.
Compressors of this type are used in applications ranging from vacuum to pressures up to 60,000 psig
(4,100 bar). Because of the large surface areas and masses and the use of water-cooled heads, our metallic
diaphragm compressors achieve higher compression ratios than conventional units. In specific cases,
compression ratios as high as one hundred to one are possible.
Two-stage diaphragm hydrogen compressor fully automated, with auto unloading system, auto-recycle, inter-stage and after coolers.
Meeting NEC Class 1, Division II, Groups B,C,D. This diaphragm compressor is Ideal for filling cylinders and trans-filling from tube trailers.
Because PDC's diaphragm compressors utilize static seals, our crankcases do not need to be purged or
vented. Due to this there is no leakage to the atmosphere.
Our design permits startup under high inlet pressure without unloading the system as required by other
compressor systems. Complicated and expensive transition assemblies used by conventional diaphragm
compressors are eliminated. Resulting in lower purchase, operating and maintenance cost.
These compressors are used for contamination-free compression of gases. The process media does not
contact the piston, piston rings, etc. that are typically used to generate displacement in conventional
compressors. PDC accomplishes this by isolating the process media from the piston and related
components with a set of metallic diaphragms. The piston moves a column of hydraulic fluid which
in turn moves the diaphragm set and displaces the process media. The process side of these units
is constructed of compatible corrosion-resistant material (stainless steel, Inconel®, Hastelloy®,
Monel®, etc.) to prevent contamination.
(2) two stage diaphragm compressors piped in parallel mounted on a common skid. PLC controls, a flow control valve, a recycle loop,
isolation valves, process filters, a set of dry contacts for remote access and a closed loop water cooling system.
Two-Stage Tetra-Fluoro ethylene (TFE)
gas diaphragm compressor system manudactured for 3M Company.
PDC metallic diaphragm compressors are ideal for compressing all gases without leakage or contamination of the process media. The advantages of ultra high purity, leak free gas handling are what differentiate a PDC diaphragm compressor from reciprocating and screw type compressors. Reciprocating and screw type machines are subject to leakage around piston rings which results in contamination of the process gas by hydraulic oil.
PDC diaphragm compressors isolate the process media from the piston and related components with a set of metal diaphragms. These diaphragms are carefully positioned inside precisely contoured cavities which are machined into the upper and lower plates of the compressor heads.
Diaphragm compressors can work with suction pressures starting at atmospheric and deliver discharge pressures as high as 60,000 psig. Because of the large surface areas of the heads and diaphragms, the continuous presence of hydraulic oil and the cooling of the process side heads, Pdc compressors will run considerably cooler than a conventional piston type reciprocating machine.
A PDC compressor in operation is more isentropic than adiabatic. The exponent runs between isothermal and adiabatic. As a result, higher compression ratios can be achieved. In some cases compression ratios as high as one hundred to one are possible. This would be difficult or impossible to achieve with conventional units.
Diaphragm Compressor Explained
The operation of a diaphragm compressor is very simple, employing basically only the gas and hydraulic systems. The gas system as depicted in Fig.1 consists of the three piece diaphragm set and the inlet and outlet process check valves.
The hydraulic system Fig.2 employs a crank driven piston that moves a column of hydraulic fluid through the suction and discharge cycles. Compression occurs as the hydraulic fluid is pushed upward to fill the lower plate cavity, exerting a uniform force against the bottom of the diaphragm set. This deflects the diaphragm set into the upper cavity that is filled with the process gas. The deflection of the diaphragm set against the upper gas plate cavity first compresses the process gas and then expels it through the discharge check valve. As the piston reverses to begin the suction cycle, the diaphragm set is drawn downward to hug the lower cavity while the inlet check valve opens and fills the upper cavity with a fresh charge of process gas. The piston passes through bottom dead center and begins its upward stroke, and the compression cycle is repeated.
Major components of the compressor system include:
Oil Relief Valve
The oil relief valve limits maximum oil (and thus gas) pressure and assures that the diaphragms completely "sweep" the upper and lower cavity contours to maximize displacement
Priming Pump
We provide an automatic, positive displacement gear pump. Priming is crankshaft driven and automatic upon start up. This eliminates priming problems that are typically associated with gravity fed pumps.
Injection Pump
PDC provides a plunger type injection system on all motor driven diaphragm units. The injectors are also crank driven and precisely meter hydraulic fluid flow during the operation of the compressor.
Cavity Design
The deflection of, and stresses on the metal diaphragms are controlled by carefully designed cavity contours. We use state of the art design and analysis tools, and cutting edge programs to model these. Optimum displacements are calculated while assuring maximum service life for the diaphragms. Finite element analysis is used to calculate the performance of the compressor heads that house these cavities. The effects of head deflection on diaphragm stress are examined to determine the effect on fatigue life.
Process Head
At PDC, we machine process heads from a wide variety of materials including 300 series stainless steel and Monel to best suit the process gas you require.
Triple Diaphragm Construction
Is the heart of the machine and refers to the stack of three metal diaphragms. The upper diaphragm (process side) is made of a material compatible with the process media. The lower diaphragm (oil side) is made of the same material as the upper, and the middle diaphragm is made of brass. Without the brass surface of the middle diaphragm, the similar materials of the upper and lower diaphragms would gall and stick together..
Process Contacting Seals
We offer an extensive variety of static elastomeric O ring seals including Buna, Viton, and Teflon, to suit the process gas you specify
Leak Detection System
Included with every PDC diaphragm compressor is a leak detection system. This system detects diaphragm or seal failure. Diaphragm failures are normally caused by particles or contamination in the gas or oil systems of the compressor, moisture condensation inside the cavity, or improper tightening of the compressor head bolts. Our leak detection system utilizes a closed chamber isolated from both the process and hydraulic sides into which any leaked media (gas or oil) will collect. Any such accumulation immediately shuts down the compressor before any contamination can occur.
Process Inlet & Outlet Check Valves
Depending on the application, PDC uses either cartridge or flat disc valves. We select the size and type of valves that will best suit the specific operating conditions and process gas because incompatible materials or improperly sized valves can seriously degrade compressor performance. Inlet and check valves are designed for easy removal and maintenance, which eliminates the need to dismantle the head assembly.
Purity of Inlet Gas
Diaphragm compressors cannot properly operate with free liquids in the gas stream. It is therefore critically important that the source gas is clean and dry and does not contain any water or oil mist, droplets, water vapor or gases that could condense during compression. To help maintain gas purity, we install process gas filters prior to each compression stage.
PDC Diaphragm Compressor Configurations
PDC compressors are available in single stage, two stage and duplex configuration. Single stage units utilize a single head that can be mounted in a vertical or horizontal position. When mounted horizontally, the user has the option of adding a second, opposing head for future expansion. A second head can be field installed and can be fitted to increase flow, discharge pressure, or both
PDC two stage compressors feature horizontally opposed heads. Properly designed, this configuration can reduce horsepower requirements thereby lowering energy costs.
PDC's diaphragm compressors are the preferred choice when contamination-free, leak-tight gas compression is required. PDC diaphragm compressors are designed to afford high quality, high reliability, low maintenance and extended service intervals. PDC users have reported up to 40,000 hours without any parts replacement needed except for oil changes.
PDC diaphragm compressors feature
State-of-the-art manufacturing
All critical components are manufactured at PDC, assuring the highest levels of quality control. In house manufacturing allows us the flexibility to accommodate tight delivery schedules.
Enhanced diaphragm life
All aspects of our diaphragm compressor design are intended to enhance component life, improve operation and reduce and simplify maintenance. Diaphragm cavity contours, which control stress in the diaphragms, are precisely machined to provide uniform stress distribution. These cavity contours are computer engineered utilizing Finite Element Analysis. Diaphragm surfaces are specially treated to extend fatigue life.
Automatic unloading system
The compressor is automatically re-primed at start-up. Incorrect priming will cause cavitation inside the compressor and could lead to damage of the heads, head bolts, diaphragms, O-rings, or the process and hydraulic systems. Automatic unloading eliminates the need for a technicians presence to re-prime the compressor.
Hydraulic oil system
The hydraulic system is designed to assure uniform diaphragm deflection, prevent knocks, vibration, cavitation and yield smooth, quiet compressor operation. Unique oil distribution techniques are employed to eliminate pressure differentials and gradients. The system utilizes an automatic priming pump, positive displacement high-pressure injection pump and oil relief valve with bypass valve for smooth, easy starting..
High Product purity
The triple diaphragm set ensures that the process gas is isolated from the hydraulic oil.
Environmentally safe
PDC uses static seals and there is no migration of process gas to the crankcase. The crankcase does not require purging or venting, so there is no leakage of process gas to the atmosphere.
Corrosion resistant wetted materials
All process contacting parts are made from stainless steel and high strength polymers. This helps to prevent premature failure of the diaphragms and reduces the cost of spares needed, reduces maintenance frequency and reduces down-time.
Safety interlocks
Features include shutdowns for low suction, high discharge, low oil, low water coolant and diaphragm or O-ring failure. Audible and visual enunciators can be supplied for an added level of protection. The compressor will be completely instrumented for automatic operation.
Lower Energy Costs
Duplex and two-stage diaphragm compressors are horizontally opposed designs which reduce horsepower requirements and energy costs.
International standards compliance
PDC diaphragm compressors can be designed and certified to comply with European, American, Canadian, Japanese and other international directives including the National Electrical Code (NEC), Canadian Standards Association (CSA), High Pressure Gas Safety Institute of Japan (KHK), and the European Union's Pressure Equipment Directive (PED) and ATEX directive for machinery.
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