Quick answer
What is the difference between swing, lift and dual plate check valves?
A swing check valve uses a hinged disc; a lift check valve has a guided closure member that lifts from its seat; a dual plate check valve has two pivoting plates, commonly with spring-assisted closing. Choose by operating flow, permitted installation, pressure loss and closing response. The design name alone does not establish suitability for pump discharge service.
KEHUA VALVE procurement guide. The references explain general valve principles; the offered model drawing, service limits and agreed inspection records establish suitability for your project.
Updated: — Linked the separate wafer check valve entry without equating its connection with a dual-plate closure; model specifications unchanged.
| Selection point | Swing check | Lift check | Dual plate check |
|---|---|---|---|
| Moving element | A disc pivots about a hinge. | A guided disc or piston lifts away from a seat. | Two plates pivot about a central hinge arrangement. |
| Closing arrangement | Identify gravity, spring or other assistance on the drawing. | Identify gravity or spring assistance and the guide arrangement. | Confirm the springs and plate travel on the offered design. |
| Installation review | Check hinge orientation, disc travel and permitted flow direction. | Check the required guide axis and mounting position. | Check hinge-pin orientation and plate clearance inside the mating pipe. |
| Hydraulic evidence | Request pressure-loss data across the operating flow range. | Review the actual flow path and pressure-loss data. | Request opening and pressure-loss data for the selected spring configuration. |
| Access for service | Check cover and disc-removal clearance. | Check access to the guided internals and seat. | Confirm whether inspection requires removal from between the flanges. |
| Pump trip review | Evaluate the offered closing response against system conditions. | Evaluate the offered closing response against system conditions. | Spring assistance does not by itself prove non-slam operation. |
Start with non-return duty and the operating flow range
A check valve allows forward flow and closes against reversal. For a pump discharge line, the buying question is how the valve behaves while the pump runs, stops and restarts. Record the fluid, minimum and normal flow, expected maximum flow and whether pumps operate in parallel.
KEHUA lists swing, lift and dual-plate check valve series. Use the series pages to identify a candidate, then request the specific configuration. A connection name such as wafer describes the installation arrangement and is not a fourth disc-motion principle. KEHUA also lists a separate wafer check valve entry; request its closure arrangement and installation drawing rather than assuming that every wafer valve is dual plate.
Swing check valves: review the hinge, flow and maintenance access
The hinged disc moves out of the flow path as it opens. Its position affects resistance, so a nominal size or a fully-open drawing is not enough to predict pressure loss during actual operation. KSB describes the dependence of swing-check flow resistance on velocity and disc position.
Ask for the permitted mounting arrangement and space needed to open the cover or remove internals. A drawing approved for horizontal service is not automatically approval for vertical service. If the line is vertical, identify upward or downward flow explicitly and obtain model-specific confirmation.
Lift check valves: check the guide arrangement and flow path
A lift design uses a closure member moving in a guide rather than swinging about a hinge. Establish whether the proposed configuration relies on gravity, a spring or both. KSB distinguishes spring-loaded arrangements and notes that changes in the flow path can increase head loss relative to a swing design.
For procurement, ask for the actual pressure-loss curve, permitted installation position and wetted-part materials. Share any particles, deposits or cleaning requirements so the supplier can review the guide and sealing surfaces. Do not assume every lift design has the same internal geometry.
Dual plate check valves: distinguish the plates from the connection
A dual plate design divides the closure into two plates. Spring-assisted versions help move the plates toward the seats as forward flow decreases; CRANE illustrates this arrangement in its public construction overview. Those operating principles do not transfer another manufacturer’s tested performance to a KEHUA model.
Where a wafer configuration is proposed, compare face-to-face length, flange standard, pipe internal diameter, gasket position and the plate envelope at full opening. Request the installation instructions for hinge-pin orientation and nearby obstructions. Confirm the actual connection instead of treating dual plate and wafer as interchangeable terms.
Pump discharge selection: pressure drop and closing response are separate
Compare pressure loss at the project’s operating flow, then review the stop or trip condition separately. A low steady-flow pressure loss does not demonstrate acceptable closing behaviour. Val-Matic’s design guide explains why check-valve selection must consider the pumping system and the potential for reverse-flow stoppage to produce a pressure surge.
For example, a duty/standby pump arrangement needs a review of what happens when the running pump trips while the other branch remains pressurised. Provide the pump arrangement, stop sequence and available transient-study data. Ask the responsible system engineer whether a transient assessment is needed and request applicable dynamic information from the valve supplier. “Non-slam” should have an agreed operating basis, not serve as an unqualified promise.
Compare quotations with a complete check valve RFQ
Use the same line-item information for each quotation. Mark unknowns as pending and request a written deviation list so technical assumptions can be resolved before the order.
- Service: fluid, phase, temperature, contaminants and minimum / normal / maximum flow.
- Pressure: operating and design conditions, backpressure and maximum reverse differential pressure.
- Piping: nominal size, actual bore, line orientation, flow direction and nearby fittings.
- Connections: flange or weld-end standard, facing, face-to-face dimension and installation envelope.
- Construction: disc arrangement, spring or gravity assistance, body, disc, pin/guide, spring and seat materials.
- Pump duty: single or parallel operation, start/stop frequency, trip sequence and available surge assessment.
- Evidence: model drawing, pressure-loss information, installation instructions, agreed tests and traceability records.
- Supply: item quantity, destination, schedule, required spares and a separate list of technical deviations.
Agree the inspection scope before accepting the offer
Keep pressure-containing shell tests, closure leakage tests and dynamic performance evidence as separate review items. Record the test standard and edition, medium, pressure, duration, direction and leakage acceptance required for the order. A successful static test is not a pump-system transient assessment.
Send the completed requirements to KEHUA for a model review and reconcile the returned datasheet, drawing and deviations. Select the combination that meets the documented service and installation requirements; there is no universal winner among swing, lift and dual plate designs.
Compare valve families
Use this guide together with the relevant valve family and project operating data.
Primary technical references
Confirm the edition required by the contract. The project specification and purchased standard remain controlling.
More technical notes