Ball, gate and plug valves

Ball, gate and plug valves control isolation by moving a closure element across the flow path. Their internal geometry, seat design and operating mechanism affect flow resistance, sealing and suitability for the process medium.

Typical applications

Pipeline isolation, process-unit boundaries and equipment connections use these valve families. The intended isolation duty and operating conditions determine the appropriate construction.

Types and configuration choices

Full or reduced bore, different seat materials and manual or actuated operation are common choices. Specify size, rating, connections, temperature and required shutoff performance.

Describe the isolation function before choosing the construction

Use the valve tag and piping schedule to identify the required function. Gate valves provide an opening or closing function through a moving gate, while ball and plug valves use rotating closure elements. These construction differences do not make every design suitable for the same service. Record whether the requirement is routine isolation, a specified shutdown function or another approved duty, and ask the proposal to address that function explicitly.

Keep continuous flow regulation separate from an isolation enquiry unless the selected design and project basis expressly require it. Ask which valve construction is offered, how it addresses the defined duty and which limitations remain. Where the enquiry permits several families, compare the proposed bore, seats, operating arrangement and maintenance access against the same requirements. A familiar family name should not replace a technical response for the actual installation.

Define actuation and accessories as a complete assembly

Identify manual operation, gearing or an actuator as part of the purchase scope. For an actuated valve, provide the approved functional requirements, available utilities, mounting interface and required signals. Ask the proposal to distinguish valve hardware, actuator, brackets, couplings, switches and control accessories. An actuator supplied separately needs an agreed integration and verification responsibility; matching a mounting pattern alone does not establish a complete working valve assembly.

For replacements, record the installed valve and drive identification and the controlled assembly drawing. Ask who reviews the operating loads and offered actuator selection for the documented duty. Keep any shutdown or safety function subject to the project's responsible engineering review. Request assembly documentation and the specified functional acceptance evidence. Do not infer a fail position, operating time or safety capability from the presence of an actuator or a generic control-box description.

Agree the valve test and release records

Define the required inspection and testing standard, edition and acceptance criteria in the purchasing specification. Distinguish pressure-boundary testing from seat or closure testing, and state the requested test medium and direction where the approved basis requires them. Ask the offer to identify which requirements are included and where witnessing or additional records cost extra. Terms such as tested or tight shutoff need a documented acceptance basis rather than an assumed universal meaning.

Request records linked to valve tags or serial identification, together with the specified material documentation, final drawing and accessory list. Treat product-family qualification and tests on the actual supplied valve as different evidence. List special-service requirements separately and ask for their applicable scope, without assuming that one certificate covers every construction. Oillinko reviews this enquiry information and coordinates sourcing manually; the catalogue does not confirm available stock, an accepted alternative or a completed valve qualification.

Bore size and pressure class

State the nominal size, required flow passage and the project's valve rating designation separately. Where full bore or passage for an inspection tool is required, attach the dimensional requirement rather than rely on the valve size alone. Give the governing design standard and edition specified by the project. Ask the offered valve's pressure-temperature basis to be identified for its actual construction and materials. A class or nominal-pressure label should not be treated as a pressure limit valid at every temperature or as proof of an unrestricted internal bore.

Body and trim materials

Identify the specified body, closure element, stem, seating surfaces and other wetted materials, including their grade or approved designation. Request a materials schedule for the proposed valve instead of accepting a single body-material description as the complete specification. Seat inserts, packing and body seals also need review against the fluid and temperature basis. For a replacement, record the installed configuration and any change in duty. Proposed substitutions should identify the affected components and evidence for review before they are accepted as equivalent.

End connections

Provide the mating flange, thread or welding-end details from the controlled piping documents. For flanged valves, include the specified standard, facing, rating and connection dimensions; for threaded or welded arrangements, retain the exact thread or weld preparation requirement. State the face-to-face or end-to-end dimension needed for a replacement and the available installation space. Ask the proposed drawing to identify differences from the existing valve. Matching nominal size does not establish a suitable joint, compatible sealing surface or a replacement that fits the existing spool.

Operating medium and temperature

Describe the process medium and available composition or contamination information, with the operating cases and temperature range established by the project. Identify conditions relevant to seats, packing and other wetted components instead of describing the valve only as suitable for oil or gas. Keep design limits distinct from routine duty and identify any required special service qualification. Ask the technical response to state assumptions and exceptions. A valve family or material name alone cannot establish suitability for a changed fluid, cleaning exposure or temperature requirement.

How related requirements differ

Globe and control valves: Globe valves regulate flow through movement of a plug relative to a seat. Control valves combine a selected valve body and trim with an actuator and control accessories to regulate a process variable. Body pattern, trim characteristics, actuator and positioner should be evaluated together. Pressure drop, fluid properties, noise, cavitation and the required fail position influence selection.

Butterfly and check valves: Butterfly valves use a rotating disc for flow control or isolation. Check valves respond to flow and pressure conditions to reduce reverse flow. These two valve families have distinct functions despite their common use in piping systems. Disc, seat and offset arrangements vary for butterfly valves. Swing, lift and dual-plate check designs require consideration of orientation, closing behavior and operating flow.

Safety and relief valves: Safety and relief valves are pressure-protection devices selected to discharge fluid under defined relieving conditions. Their capacity and configuration depend on the protected system and the approved relief design basis. Spring-loaded and pilot-operated arrangements have different characteristics. Set pressure, relieving capacity, back pressure, materials and certification requirements must be specified for the actual installation.

Compare the complete supply scope

For ball, gate and plug valves, compare the complete assembly and documented scope of supply. An offer for a component may exclude the drive, controls, fittings, accessories or inspection services needed for the installation. List exclusions and proposed alternatives so each quotation can be assessed against the same requirement. Manufacturing origin, delivery location and the supplier's business address are separate facts. If a particular origin is required, request confirmation for the actual offered item and the supporting documentation specified by your project.

Questions before requesting a quotation

What information should be available first? Start with the intended application and the current technical specification for ball, gate and plug valves. In this category, the initial review includes bore size and pressure class, body and trim materials, end connections, operating medium and temperature. 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.