Reciprocating compressors
Piston compression packages and components for gas duties across specified pressure stages.
Reciprocating compressors compress gas in cylinders using pistons and inlet and discharge valves. Cylinder arrangement, staging and lubrication are selected for the gas composition and the required pressure and capacity.
Typical applications
Gas gathering, process compression and high-pressure gas duties commonly use reciprocating machines. Pulsation and mechanical loading form part of the package design.
Types and configuration choices
Oil-lubricated and non-lubricated arrangements serve different cleanliness needs. Check stage conditions, cylinder materials, packing, cooling and the required auxiliary systems.
What should a reciprocating compressor RFQ contain?
A useful reciprocating compressor RFQ combines a gas analysis, a schedule of operating cases and a defined package boundary. Begin with the intended service: for example, an existing gathering installation, a process compression duty or a replacement package. Explain the result the plant needs rather than choosing a frame solely from a headline power rating. Give each duty case a reference that can also appear in the supplier's performance schedule. Record who owns the process data, who will review the proposed selection and which inputs are still awaiting confirmation. This creates an enquiry that can be revised without losing the basis on which the initial quotation was prepared.
Separate requirements into process, mechanical, electrical, control and documentation schedules where the project already uses those disciplines. A first enquiry can be preliminary, but it should say so and list the missing inputs. Request the calculation basis, equipment arrangement and deviations with the commercial response. For a replacement, include the installed equipment references, current operating conditions and the reason for replacement. Photographs are useful for identification and access planning; they should not substitute for a reviewed interface drawing. A concise cover note plus controlled attachments is easier to compare than specifications scattered across emails with conflicting revisions.
How do operating cases affect package selection?
Compare proposals using a common case schedule. The schedule should pair gas flow, composition, suction conditions and required delivery conditions for each real operating state. Label normal duty, minimum throughput, peak demand and any future case that is genuinely required. Do not combine the highest flow from one case with the lowest suction pressure from another unless the process team intends that combination to be evaluated. Ask the bidder to identify the proposed configuration and power demand for each case, together with any case it cannot cover. This makes a limitation visible before it becomes a disagreement over a nominal capacity figure.
An illustrative comparison is two proposals that both state the requested maximum flow. One evaluates that flow at the normal suction condition, while the other evaluates it at the specified low-suction case. Their headline capacities look comparable, but their calculation bases differ. Resolve the case mismatch before considering the price difference. Require the technical review to address the offered machine's loading and operating limits, and retain the supporting application calculation with the proposal. A purchasing comparison should not attempt to establish those limits through a generic online formula or turn an unverified sales statement into a project performance guarantee.
Which auxiliaries belong in the compressor package?
Define the boundary between the compressor assembly and the complete compression package. Ask the quotation to identify the driver, coupling, base or skid, cooling arrangements, lubrication systems, instrumentation, controls and required process auxiliaries as included, excluded or supplied by others. Describe the interface with upstream gas conditioning and downstream equipment. If separators, interstage coolers, pulsation-control equipment or associated piping are required by the package design, make their design and supply responsibilities explicit. The enquiry should also identify who prepares the relevant engineering studies and who approves their findings. A list of component names alone does not establish an integrated package scope.
Site information should include the available utilities, location conditions, electrical requirements, space limits and the project documents governing installation interfaces. Ask for a general arrangement drawing showing connection locations and the access needed for maintenance and component removal. Separate shop assembly from field assembly, commissioning support and any site acceptance work. These boundaries are particularly useful when one offer includes a skid while another includes only the compressor assembly. Record the agreed responsibility matrix with the selected proposal so later accessories are assessed against a documented boundary rather than assumed to be free additions.
How should lubrication and gas cleanliness be specified?
Describe the permitted process contamination and the downstream equipment's cleanliness requirements before comparing lubricated and non-lubricated cylinder arrangements. Ask which parts of the offered package use lubricant and what carryover assumptions underlie the proposal. Gas composition, contamination and operating conditions require an application-specific lubrication review. Do not select lubricant type or quantity from a general procurement guide. State whether any downstream oil-removal scope is included and which party must demonstrate the required outlet quality. If a bidder uses an expression such as oil-free, request a precise explanation of the package boundary and the conditions to which the statement applies.
For a replacement or modification, distinguish the historic gas basis from today's measured composition and duty. Provide records of changed service conditions to the responsible reviewer, together with the installed cylinder and packing references where available. Ask for any resulting changes in materials, cooling, vent interfaces or auxiliary requirements to be listed as part of the offer. This review also helps distinguish an equivalent replacement from a proposed reconfiguration. Treat recommendations affecting operation as controlled technical deliverables requiring the appropriate approval; the quotation exercise should collect the evidence and responsibilities rather than instruct site personnel to alter lubrication or protective settings.
Which inspections and documents should be requested?
Request a project-specific inspection and documentation schedule with the proposal. Identify the technical datasheet, performance calculations, general arrangement, utility requirements, material records, electrical and control documents, manuals and the agreed test reports. Where a project standard applies, state its required edition and scope in the enquiry and ask for a clear compliance or deviation response. Separate a component certificate from evidence covering the complete assembled package. An organizational certificate, a catalogue statement and a witnessed package test are different records; the purchasing file should show which evidence actually supports each acceptance requirement.
Agree the proposed shop tests and acceptance criteria before comparing claims about a tested package. Identify the test boundary, medium or method, conditions, measurements, witnessing arrangements and report deliverables through the approved test plan. Record what must be checked at site and who supplies the resources for it. For replacements, link the documentation to the exact equipment identity and drawing revision. Request a final document index and explain which records are needed before dispatch or acceptance. This keeps reviewable deliverables separate from an unspecific promise that certificates will be supplied later.
How can buyers compare compressor quotations fairly?
Build the comparison around the same case schedule and scope matrix. For each offer, record the selected arrangement, covered duties, driver and auxiliary scope, interfaces, required evidence, deviations and information still needed from the buyer. Keep technical acceptance separate from the commercial comparison. Record the currency, price basis, named delivery location, quotation validity, proposed lead time and the event from which that lead time starts. Manufacturing origin means the country in which the offered equipment is manufactured; it is not established by the quotation sender's address. Request origin information at the appropriate assembly or component level where the project requires it.
A lower assembly price may require separate purchases or engineering work to produce the same package boundary. Show those gaps explicitly instead of inventing an estimated complete price. Likewise, distinguish a budget quotation from an offer with reviewed process inputs and an agreed scope. Submit your datasheet and case schedule to Oillinko for manual review and clarification; this page does not establish stock, an appointed manufacturer or an accepted design. The related equipment and inspection guides below help define connected scopes without treating those items as automatically included in a compressor offer.
Gas analysis
Provide the gas composition and its measurement basis, including the sampling date, units and expected variation between operating cases. Identify water, liquids, particles and constituents requiring a materials or emissions review. A description such as natural gas is insufficient for a package selection. Separate measured values from assumed values and explain whether an upstream treatment package forms part of the enquiry. Request a documented application review for the offered configuration; a previous selection for a similar stream does not establish suitability for this gas.
Stage pressures and temperatures
Identify suction and required delivery pressure for each operating case, stating whether pressure is absolute or gauge. Give inlet temperature and available cooling conditions alongside the gas analysis. Distinguish the process requirement from the proposed number of stages and the resulting interstage conditions, which should be explained in the technical offer. Keep design limits separate from normal operation. Ask for a case-by-case performance schedule with assumptions, limitations and the package boundary used in the calculation, rather than comparing a single discharge pressure printed in a brochure.
Capacity and duty cycle
State gas flow with units and its reference conditions; a standard volume and an actual inlet volume are different quantities. Describe normal, minimum, maximum and future cases, including which cases occur together and the expected hours of service. Identify the required capacity-control range and the site's electrical or driver constraints without prescribing an unreviewed control method. Request power and performance information for the same cases from every bidder. Keep continuous duty, standby provision and intermittent operation separate in the enquiry so an attractive rated capacity does not conceal a different service basis.
Cylinder and packing requirements
Record process cleanliness limits, permitted lubricant carryover, service constituents and project restrictions affecting cylinders, seals and rod packing. For an existing machine, supply its cylinder, packing and drawing references as well as the frame identity. Ask the technical proposal to describe the selected arrangement, required cooling and vent interfaces, and the application assumptions behind it. A non-lubricated cylinder description does not automatically describe every lubrication system in a complete package. Material and sealing compatibility remain matters for documented application review, with alternatives and unresolved inputs clearly identified.
How related requirements differ
Centrifugal compressors: Centrifugal compressors increase gas pressure using rotating impellers and stationary flow passages. Gas composition, inlet conditions and the required pressure ratio influence the compressor's performance and its operating envelope. Single-stage and multistage packages may use different drivers and sealing systems. Compare all operating cases, anti-surge control, materials, utilities and package boundaries.
Screw compressors and blowers: Screw compressors trap and compress gas between rotating elements. Blowers move gas at comparatively modest pressure differences; the required duty determines whether a compressor or blower arrangement is appropriate. Oil-injected, oil-free and packaged blower options have different utilities and maintenance needs. Compare medium, flow, pressure, discharge temperature, noise and enclosure requirements.
Gas and steam turbines: Gas and steam turbines convert energy in a flowing working fluid into shaft power. They can drive generators or rotating machinery, with different fuel, steam and auxiliary-system requirements for each turbine arrangement. New packages and replacement parts require different technical information. Identify the turbine configuration, power and speed, fuel or steam conditions and required control interfaces.
Compare the complete supply scope
For reciprocating compressors, distinguish an assembly quotation from a complete gas compression package. Compare the driver, cooling, process auxiliaries, controls, engineering studies and agreed tests using the same boundary. Identify field connections, utilities and commissioning work supplied by others. Request a list of departures from the case schedule and scope matrix, with their effect on the proposed selection. Keep manufacturing origin, dispatch location and delivery terms as separate entries. A preliminary assembly price should remain visibly preliminary until the required interfaces and included work have been reviewed.
Questions before requesting a quotation
What information should be available first? Start with the intended application and the current technical specification for reciprocating compressors. In this category, the initial review includes gas analysis, stage pressures and temperatures, capacity and duty cycle, cylinder and packing requirements. Attach the relevant drawings or scope documents and identify any information still awaiting confirmation. This makes it possible to distinguish a preliminary enquiry from a fully defined purchasing or service requirement.
Can an alternative be accepted on size or price alone? A proposed alternative needs review against the required function, materials, interfaces and documented performance. Similar dimensions or a familiar brand name do not establish compatibility. State which requirements are mandatory and where an equivalent may be considered. Availability, lead time and supporting documents are confirmed for the actual offer rather than assumed from this catalogue.