Diaphragm Compressors

Diaphragm Compressors

PDC Machines has been manufacturing industrial diaphragm gas compressors since 1977. Our diaphragm compressors are the preferred choice for high purity and leak tight gas compression applications. We have developed an extensive line of basic diaphragm compressors and fully automated turnkey diaphragm process gas compressor systems with installations located around the globe.

We design basic- to fully-instrumented leak-free, non-contaminating reciprocating diaphragm gas compression systems in accordance with customer specifications and API 618 (some exceptions/deviations, see Specifications). Our compressors range in size from 3 hp(2 kW) to 200 hp(150kW). Discharge pressures range from 50 psi to as high as 15,000 psi (1,100 bar) and typical flow rates based on compression ratio to 500 Nm3/hr.

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  • Single stage diaphragm compressor for pumping methane, helium and hydrogen mixture to be used as part of a specialty gas mixture production. Discharge pressure up to 6,000 psig/414 barg, flow 15 scfm/24 Nm/3hr and 20 hp/15kW. Destination Houston, Texas, USA.

  • Two-stage diaphragm compressor model PDC-3-550-2500 (50) for compressing xenon gas. Discharge pressure is 3,000 psig/207 barg, horse-power 5 hp/3.7 Kw and flow rate is 12 Nm3/hr. Scope of supply includes VCR fittings, orbital welding, oxygen cleaned process piping and a closed loop water cooling system.

  • Two-stage diaphragm compressor with PLC programmable controls to boost discharge pressure up to 7,000 psig/482 barg for filling cylinders with helium, nitrogen and argon gas mixtures. 10 hp/7.5 kW motor.

  • Two-stage diaphragm reciprocating compressor, model PDC-3-300-600 for compressing Deuterium gas. Scope of supply included a closed loop water cooling system and heat tracing of hydraulic oil piping and compressor heads for cold climate operation as well as a control panel, motor starter and safety inter-lock switches.

  • Two-stage diaphragm compressor for compressing hydrogen and North Sea natural gas mixture. The compressor is installed inside a container. Scope includes a closed loop water cooling system, gas detection system with warning lights, heater for low ambient conditions and heat tracing of hydraulic piping and process heads for cold climate operation.

  • Carbon dioxide recycle compressor, discharge pressure 1,800 psi/124 barg and 10 hp/7.5 kW motor.

  • Single stage compressor installed at a national laboratory in the United States. Scope of supply includes block and bleed valves, VCR fittings and orbitally welded tubing, pressure transmitters, pressure safety valves, heat tracing of hydraulic piping and heads and crank-case heater.

  • These two single stage compressors are for a Propylene gas mix. Block valves for each instrument allows serviceability in the field with little down time. Other features include custom tie in connections for nitrogen purging, flare stack, and water separation. They feature a Siemens PLC, and an AC unit to keep the control panel cool in out-door ambient conditions up to 130°F/54°C and a recycle flow control valve for a precise flow regulation.

  • Single-stage compressor for mixed gases (oxygen, nitrogen & helium). Boosting pressure from 2,900 psig/200 barg to 8,400 psig/580 barg with a flow rate of 373 scfm/600 Nm3/hr. 75 hp/55 kW motor. Scope of supply includes closed loop water cooling system, fire resistant oil and heat tracing and insulation of oil lines and compressor head for cold climate operation. The compressor complies with European PED and CE directives.

  • Two-stage compressor Pumping tetrafluoroethylene (TFE) gas boosting pressure from 15 psig/1 barg to 300 psig/21 barg with a 50 hp/37 kW motor.

  • Two-stage compressor for Argon service boosting pressure from 500 psig/34 barg to 6,500 psig/448 barg with a 10 hp/7.5 kW motor.

  • Two-stage 10 hp/7 kW motor diaphragm compressor for pumping deuterium gas. This membrane compressor boosts pressures from 5 psig/0.3 barg to 600 psig/41 barg. Scope of supply includes heat tracing and insulation of the heads and hydraulic piping for cold climate operation. The control panel is also UL listed.

  • Two-stage 5 hp/3.7 kW motor diaphragm compressor for pumping tetrafluoroethylene (TFE) gas. This membrane compressor boosts pressures from 15 psig/1 barg to 700 psig/48 barg. Scope of supply includes heat tracing and insulation of the heads and hydraulic piping for cold climate operation.

  • This two-stage diaphragm compressor was shipped to the Middle East as a turnkey system for oxygen service. The scope of supply included fire resistant oil. This compressor is designed up to 3,000 psig/207 barg discharge pressure with 12 scfm/19Nm3/hr flow. Horse-power is rated at 10 hp/7kW and the compressor is rated for class 1 Div.II.

  • This single-stage 15 hp/11kW diaphragm compressor was shipped to North Africa as a turnkey system for hydrogen service. The scope of supply included a discharge transmitter to more specifically monitor compressor output pressure, Allen Bradley PLC with Ethernet or Micrologix communication to customer DCS.

  • Two stage diaphragm compressor for pumping vinyl fluoride, 350 psig/24 barg discharge, flow is 80 scfm/129 Nm3/hr.

  • Three stage PDC-4 series compressor for pumping neon and fluorine mix. Boosting pressure from 29 psig/2 barg to 2,190 psig/151 barg and a flow rate of 35 scfm/56 Nm3/hr. Has two 24hp/18 kW motors.

  • Two stage PDC-4 series compressor for pumping oxygen gas. Boosting pressure from 58 psig/4 barg to 2,500 psig/172 barg and a flow rate of 13 scfm/21 Nm3/hr. Has one 20 hp/15 kW motor.

  • Coal Gasification based Syngas Compressor supplied to Turkey. PDC-13 series two stage compressor, 151 hp/113 kW motor, boosting pressure from 145 psig/10 barg to 435 psig/30 barg. Compressor complies with ATEX.

  • Compressor PDC 4 series, duplex for pumping natural gas. Discharge pressure 300 psig/20 barg. Scope of supply includes: Buffer vessels, level switch, vibration switch, temp indicator, temp RTD, temp switch, temp transmitter, Differential pressure transmitter, Pressure indicating transmitter, Dual oil filter and Pressure control valve.

  • Two stage PDC-13 compressor. Scope of supply includes nitrogen purge line, buffer vessel, level switch, vibration switch, temperature indicators, temperature element, temperature switch, temperature transmitter, differential pressure transmitters, dual oil filter, pressure control valve, oil heater and thermostat.

  • 2-Stage Diaphragm Compressor PDC-13-900-3000-100% for Hydrogen Gas. The flow rate is up to 700 Nm3/Hr at 2.0MPa/290 psig suction and 20.0MPa/2,900 psig discharge pressure. Power consumption is 150 HP/132 kW. This reciprocating diaphragm compressor meets plant codes and standards. The scope of supply is a turnkey system including one interstage pulsation dampener, one discharge dampener, a flame-proof motor, unloading system and PLC control, etc. 100% Butt-Welded and Radiographed Process Piping & Vessels.

  • Duplex diaphragm compressor PDC-13-2250-2250 for recirculating hydrogen gas. The flow rate is up to 621 scfm/1,000 Nm3/Hr at 2,175 psig/150 barg discharge pressure. Power consumption is 100 hp/75 kW. This reciprocating diaphragm compressor meets plant codes and standards. The scope of supply is a turnkey system including one suction pulsation dampener, a flame-proof motor and junction boxes, PLC control, etc. 100% Welded and Radiographed Process Piping & Vessels.

  • PDC-4-1000-3500 Helium Compressor used as part of a trans-filling system. This compressor allows our customer to draw their tube trailer down to under 100 psig/7 barg and still maintain a flow rate of 20 scfm/32 Nm3/hr. It comes fully instrumented with an integrated closed loop cooling system and automatic unloading.

  • PDC-13-1250 Reciprocating Diaphragm Compressor. Suction Pressure: 355 psig/24.5 barg, Discharge Pressure: 1,160 psig/80 barg, Required Flow Rate: 45 Kg/Hr Hydrogen Gas, HP: 55 kW/~75 hp. This compressor included an ESD (emergency shut-down) control philosophy for each monitoring point throughout the system; thermowells for the process RTDs, block and bleed integral manifold valves for all pressure transmitters; 4 separate junction boxes in addition to the Local Control Panel. All process piping was butt-welded and 100% radiographed, and all cooling piping was socket welded.

  • PDC-4-12,000 high pressure 800 barg compressor for nitrogen service for testing vehicle Supplemental Restraint Systems or “air bags”.

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Features    |    Applications    |    Specifications

Serving Many Industries

Our leak free and oil free, gas, non-lubricated reciprocating diaphragm compressors are found in virtually every industry worldwide. These include:

  • Alternative Energy/Hydrogen refueling stations
  • Chemical and Petrochemical (CPI)
  • Oil & Gas
  • Specialty Gas
  • Power Generation
  • Pharmaceutical
  • Semiconductor
  • Food & Beverage
  • Research & Development
  • General Industrial requirements worldwide

At the request of our customers, PDC Machines can package our compressors and customers equipment and instrumentation inside a container.

Highly reactive gases service
For compression of oxygen, fluorine, silane, phosphine and other highly reactive gases, PDC Machines performs rigorous cleaning procedures in a clean, dust-free environment. We use fire-resistant oil for the hydraulic system. We construct the process side diaphragm as well as the inner and outer check valve components.

Diaphragm Gas Compressors Explained

A diaphragm compressor is a positive displacement machine which consists of a hydraulic system and a gas compression system. Diaphragm compressors are somewhat traditional in the sense that the hydraulic system uses a linear reciprocating piston attached to a crank shaft that is driven by an electric motor. The hydraulic piston travels through a cylinder which moves a column of oil. This oil is used to lubricate the lower end running gear and to energize the gas process system.

The gas processing system consists of the gas head assembly, three metal diaphragm plates and the compressor check valves. When the hydraulic oil is pumped to the underside of the diaphragm set they flex through a contoured cavity in the gas head as the compressor check valves allow for the process gas to flow in & out of the compressor.

Triple metal diaphragm compressors are unique because they are leak-free and non-contaminating since they do not utilize dynamic seals and the diaphragm set completely isolates the process gas from the hydraulic system. Each compressor also includes a leak detection system that monitors the integrity of the diaphragms and static o-rings. Breaches in these components can signal an alarm and or automatically shut down the compressor.

Why PDC Machines’ Diaphragm Compressors

Non-contaminating Gas Compression

The triple diaphragm set ensures that the process gas is completely isolated from the hydraulic oil. The compressor does not use dynamic seals eliminating the potential for seal particulate to be imparted to the gas stream. Filters and oil removal systems are not necessary – Hydraulic oil cannot migrate into the process gas.

High Compression Ratio

Our metallic diaphragm compressors can achieve typical compression ratios up to 10:1 for certain models.

Superior & Extended Diaphragm Life

All aspects of diaphragm compressor design are intended to enhance component life, improve operability and reduce and simplify maintenance.Diaphragm cavity contours, which control stress in the diaphragms, are carefully controlled to provide uniform stress distribution. Special manufacturing processing is used on the diaphragm surfaces to enhance fatigue life.

Many of our customers have experienced continuous running times of 10,000 to 40,000 hours between routine maintenance minimizing the need for spare parts replacement.

Variable Suction Pressure

PDC compressors are capable of sub atmospheric as well as high suction pressures. Compressors can be used in in applications requiring low or high compression ratios. And for applications requiring intermittent or continuous service duty.

Many of our customers have experienced continuous running times of 10,000 to 40,000 hours between routine maintenance minimizing the need for spare parts replacement.

Unique Oil Distribution System

The hydraulic system is designed in such a way as to assure uniform diaphragm deflection, prevent knocks, vibration, cavitation and yield smooth, quiet compressor operation.

Fast Acting Leak Detection System

To detect and indicate diaphragm and seal failure.

Safety Interlocks

The compressor will be completely instrumented for safe and automatic operation.

Environmentally Safe

Our diaphragm compressors use static seals. There is no migration of gas to the crankcase as such the crankcase does not require purging or venting. The gas system integrity is monitored to preclude leakage of gas to the atmosphere.

Safe Compression of Corrosive Gases

We use non-flammable hydraulic fluid and all process-wetted components which are constructed from corrosion-resistant materials for processing of corrosive or oxidizing gases for safe operation and which will prolong the life of maintenance components.

High Discharge Pressure

PDC’s gas diaphragm gas compressors are capable of providing discharge pressures to 15,000 psig/1,000 barg and beyond.

Automatic Unloading System

The compressor is automatically re-primed at start-up. Manual start-up requires an experienced compressor technician to be present all the time to re-prime the compressor. Incorrect priming will cavitate the compressor and damage the heads, bolts, diaphragms, o-rings, process and hydraulic system.

Quiet Operation

Below 85 dBA @ 1 meter without sound-proofing enclosure.

Low Maintenance

Typically, only routine oil changes are necessary.

Low Energy Costs

PDC compressors use a heavy flywheel to provide energy. In addition, Duplex and two-stage diaphragm compressors can be horizontally opposed designs to further reduce horsepower requirements and energy usage.

International Standards Compliance

PDC’s’ diaphragm compressors can be designed and certified to comply with Canadian, European, South Korean, Japanese, North American and other international codes and standards.

ISO 9001 Quality Management

PDC is certified according to ISO 9001 standards for quality management of production and services.

Diaphragm Compressor Components

Oil Regulating Valve

The oil relief valve limits maximum hydraulic (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 Machines 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 and resultant stresses in the metal diaphragms are controlled by carefully designed cavity contours. We use state of the art design and analysis tools as well as cutting edge programs to model these.

Process Head

At PDC Machines we machine process heads from a variety of materials for process gas compatibility. 300 series stainless steel is the standard used for most applications.

Triple Diaphragm Construction

The diaphragm set consists of three plates. The upper or process side, the lower or hydraulic side and the middle diaphragm. The middle diaphragm is brass to preclude galling. The upper and lower are typically 301 SST for most applications. However, the upper diaphragm material can be supplied in alternate materials, such as Inconel 718, for process compatibility.

Process Contacting Seals

We offer an extensive variety of static elastomeric O-ring seals for process gas compatibility, options include Buna-N, Viton, and Teflon encapsulated Viton and Kalrez.

Leak Detection System

Included with every PDC Machines diaphragm compressor is a leak detection system. This system detects diaphragm or seal failures. Our leak detection system monitors the gas and hydraulic sides of the compressor and will alarm and or shutdown the compressor when an anomaly is detected. Proper maintenance, operation and clean/dry process gas promotes component operating life.

Process Inlet and Outlet Check Valves

Compressor process check valve design is dependent on operating conditions and the process gas itself. PDC compressors typically utilize cartridge or plate style check valves. Valves and valve pockets are designed for easy removal and maintenance.

Automatic Unloading System

The compressor is automatically hydraulically re-primed at start-up and unloaded upon shutdown. This process is an important procedure which will not only provide for maximum efficiency but also eliminates the need for an operator to start-up/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.

Safety Interlocks

Features include shutdowns for low suction pressure, high discharge pressure, low oil pressure, low water coolant and diaphragm or O-ring failure. Audible and visual annunciators can be supplied for an added level of protection. The compressor can be completely instrumented for automatic operation.


Awards and Certifications