Diaphragm Compressors for leak-tight and contamination-free compression of most gases including Argon, Fluorine, Oxygen, Hydrogen, Nitrogen, Helium, Ethylene, Sour gas, TFE, and many other specialty gases.
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Compressor Formatted Technical Compressors Information
Designed and
Constructed for
High Reliability and
Low Maintenance
Pdc's metallic diaphragm compressors are ideal for compressing all types of gases without incurring any contamination of the process media or leakage of gas to ambient air that results from reciprocating and other types of compressors. Traditional reciprocating compressors are subject to leakage past the piston rings which can result in contamination of the process gas with the hydraulic oil.
This is accompolished by isolating the process media from the piston and related components with a set of metal diaphragms. The piston moves a column of hydraulic fluid, which in turn moves the diapharagm-set, and displaces the process media. The process side of these units is constructed of corrosion-resistant
matearials to prevent further contamination.
Diaphragm compressors are will-suited for applications ranging from vacuum to pressure as
high as 60,000 psig. Because of the lkarge surface areas of the heads and diaphragms, the presence of pulsing oil and cooling of the upper heads(process side) Pdc compressors typically run considerably cooler than conventional piston-type reciprocating compressors.
Our compressors are more isentropic than adiabatic. The exponent runs between isothermal and adiabatic. This makes it possible for higher compression ratios to be achieved that would be difficult or impossible to achieve with conventional units. In some cases, compression ratios as high as one hundred to one is possible.
The deflection and inherent stresses of the metal diaphragms are controlled by a carefully designed cavity contour.
We use state-of-art design and analysis with the assistance of sophisticated computers to create these cavity contours. Optimum displacements are obtained while assuring maximum fatigue life for the diaphragms. Finite element analysis is used to calculate the deflections of the compressor heads that house these cavities. The effects of heard deflection on diaphragm stress are superimposed to determine their affect on fatigue life.
Oil Relief Value-
This relief value will accompolish the following:
A. Limits maximum oil and gas pressire generated by the diaphragm unit.
B. Assures that diaphragms completely sweep the cavity and contact the upper cavity controu, thus maximizing dispacement. This is achieved by cretaing oil pressure that is slightly higher than the process discharge pressure. Additional plunger movement accomplishes this after the diaphragms contact the upper cavity contour and the relief value setting. Once the relief value pressure setting is achieved, the excess oil is discharged through the relief valve and returned to the crankcase. This oil flow is referred to as "Over pump".
Injection Pump
Pdc provides an automatic plunger type injection pump on all motor driven diaphragm units. The pump's function is to inject a specific volume of oil during the suction stroke of the machine. This volume of oil compensates for the following losses:
1. Normal leakage of oil across the hydraulic piston.
2. Compressibility of oil under pressure.
As the design pressure approaches 10,000 psig, very high loads are generated between the upper and lower heads. On lower pressure design, this load is offset by a series of bolts torqued to a specific value. Attemping to accomplish this on high-pressure designs results in impractical bolt sizes and torques. The best solution is a bootstrap design.
With a boot strap configuration, there is an annular area greater than the cavity seal area that is subjected to the same hydraulic oil pressure providing a higher load than the load developed on the cavity seal area.
This offsetting load will keep the heads clamped together without the need for large bolts and high torques. We perform detailed, finite element analysis tostudy the stresses and deflections that could adversely affect normal opercation under these high-pressure conditions.
Unique Design features of Pdc Compressors
1. To achieve maximum fatigue life for the diaphragm set, we carefully design the cavity contours in the head assembly(process and oil side). Different philosophies are used for suction like vacuum, atmospheric and high pressures. Unique cavity cofigurations are used for pressures above 3000 psi.
@. Critical consideration are inherent in sizing cavity volume and piston displacement at various pressure levels to assure uniform movement of diaphragms, equialization of gas and oil pressures, and smooth start-ups, and subsequent starts.
3. Special processing of diaphragms. Customers are reporting diaphragm lives of 10,000m 25,000 and 42,000 hours of operation.
4. Unique hydraulic oil distrubution enables the compressor to run smoothly and quietly without soundproofing enclosure.
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Process Head:
At Pdc, we machine process heads from a wide variety of materials, such as stainless
steel, Hastelloy, Inconel, and Monel, to best suit the process gas you require.
Triple Diaphragm Construction-
This is comprised of a stack of three metal diaphragms.
The top diaphragm(process side) is made of a material compatible with the process
media(stainless steel, Monel, etc). The
bottom diaphragm(oil side) is made of the same materials as the upper and the middle
diaphragm is made of brass. Without the
brass-bearing surface of the middle diaphragm, the similar materials of the upper and the
middle diaphragm, the similar materials of the upper and lower diaphragms would exihibit a
tendency to gall-sticking together.
Process Contacting Seals -
We offer an extensive variety of static elastomeric O-ring seals, such as Viton, Buna,
Vespel, Teflon, Peak, and Kalrez, to suit the process gas you specify |
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Leak Detection System-
We make a leak-detection system standard on every stage of compression for Pdc diaphragm
compressors. This sytem detects diaphragm
failure,(cracked diaphragm), gas and/ or seal failure.
Diaphragm failures are normally attributed to 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 set of three diaphragms, a closed chamber into which
leaked media(gas or oil) accumulates, a relief value, pressure gauge, pressure switch, and
manual blown-down value which is normally closed.
We use triple diaphragm construction to detect diaphragm and main seal(gas or oil)
failure. The middle brass diaphragm has
radially scribed line on both sides of the diaphragm.
These serve as leak paths for moving any media that have leaked through a crack in
either the upper or lower diaphragm to the leak collection area. Any failure of either the main oil or gas seal(O-ring)
would also be detected in the leak collection area. |
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Process Inlet & Outlet
Check Valves-
Pdc uses either cartridge or flat disc values manufactured from Vespel, Peek, or Monel. We select the size and type of valves that will
best suit the specific operating conditions and process gas. Incompatible materials of construction and or
improperly sized valves can seriously degrade compressor performance. We have also designed our valves to be easily removable for maintenance without
the need to dismantle the head assembly.
Diaphragm Life &
Maintenance -
Pdc is continously striving to extend diaphragm life.
Our goal is to minimize down time, spare parts, and maintenance costs for our
customers. We are committed to extensive R&D to develop new techniques to further
reduce diaphragm stresses and extend fatigue life through advances in engineering design
and manufacturing processes. Increasing diaphragm life reduces down-time and cost of
spares. |
Quality Control is our top priority. Incoming, in process, and final inspection ensure very high quality levels. The majority of our low-quantity, custom-designed and machined parts are one hundred percent inspected.
We have developed highly efficient methodology to reduce Inspection time, without sacrificing accuracy. Compressor cavities are measures on CNC machines and a computer printout provides documentation. Computerized coordinate measuring machines and digital optical comparators are used for part inspection.
Thorough testing of all custom-designed products is another way we assure the quality and reliability of our products. Units are assembled, tested and then disassembled for visual inspection prior to reassembly and shipment.
Products from Pdc:
* Reactors
* Magnetic Mixers
* Syringe Pumps
* Lab Scale Reaction Systems
* Pilot Plants
ADVANTAGES:
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* All process-wetted
components are constructed from corrosion resistant materials. Proper oil and suitable construction materials
insure sage handling of compressors serving explosive gases.
* Design pressures from
atmospheric to 65,000 psig. Self-clamping
boot strap designs for pressures over 10,000 psig.
* Fast-acting leak
detection system to indicate diaphragm and seal failure.
* Superior diaphragm life
due to proprietary cavity contour designs and manufacturing process. This reduces diaphragm stress and extends
diaphragm life to potentially exceed 40,000 hours of operation.
* All of our models are
equipped with automatic positive priming and injection pumps to minimize knowks,
cavitation, and vibration for smooth start-up, operation and re-priming during subsequent
start-ups.
* Self energizing seals(O-rings). |
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* Ductile metal seals to
meet low leak rate specifications(10 SCCS Helium).
* Off-loading to local
storage is possible without the need for a regulator and reduced suction. This conserves energy and lowers costs.
* Reliable,
state-of-the-art components are procured from industry-respected suppliers who are
recognized for the performance, quality and durability of their products.
* High compression ratios
per stage. An application that would require
two stages on a reciprocating compressor can be handled with one stage by a diaphragm
compressor. This reduces capital costs and
maintenance.
* Cutting-edge technology
in design, manufacturing, and testing results in competitive pricing and lower maintenance
costs when compared with standard piston compressors with clean-up systems and non-lube
compressors.
* Pdc offers the
fastest turnaround in the industry. We can
typically deliver popular models in as little as 6 to 8 weeks. |
* Simplex, duplex, and multi-stage compression.
* Easy to install and maintain.
* Reduced rod load lowers torque and horse power.
* Only compression loading is on the rod.
* Duplex unit provides twice the flow and 1/3 Hp consumption.
* Fields convertible from simplex to duplex or two-stage operation to provide twice the flow.
* Capable of compressing different gases simultaneously.
Purity of Inlet Gas
Diaphragm compressors, by design, cannot tolerate any free liquids in the gas stream. So it is important for the source gas to be clean
and dry, i.e., it does not contain water mist, droplets, oil mist, water vapor, or other
gases that could condense during any phase of compressor operation through final diacharge. To help maintain gas purity, we install single or
dual 10 micron inlet filter systems.
Electrical/Systems Integration
* Can meet American, Japanese and European
Codes and Standards Design Codes
ASME, PED(Europe), NEC< CE marking, KHK(Japan), API< etc...
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Highly Reactive Gases Service
For compression of oxygen,fluorine, and other highly reactive gases, Pdc performs
regorous cleaning procedures in a clean, dust-free environment. We use fire-resistant Halocarbon oil for the
hydraulic system. We construct the
process-side diaphragm, as well as the inner and outer check value components, from Monel,
and or Inconel 718.
Stainless Steel Versus Carbon Steel Fabrication Materials
Pdc's standard material for all wetted-process compoents is stainless steel. Carbon steel heads and piping, though seemingly
cost-effective, can result in rust formation and migration of gas in the cavity, leading
to premature failure of diaphragms increasing the cost of spares, maintenance frequency,
and causing more down-time. |
Representative:
"AMARICAR
ENGINEERING & SYSTEMS"
No.61,Montieth
lane,
Egmore, chennai-600008,India
Phone
: + 91- 44- 28554689/28554230
Fax : + 91-44-52043674
E-mail : amaricar@eth.net