Check ValvesModerate2–4 hours to assess, 4–8 hours for design change4 steps

Check Valve Chattering / Rapid Opening and Closing

Check valve chatter (rapid, repeated opening and closing of the disc) causes severe impact damage to the disc, seat, and hinge pin, and can cause piping fatigue. It occurs when the flow velocity is insufficient to hold the disc fully open.

Symptoms

Loud metallic clanging or rapid banging sound from the valve locationDisc or hinge pin shows impact damage (peening, spalling) on inspectionVibration at the valve and in the adjacent pipingFrequent check valve failures requiring replacement

Root Causes

1

Insufficient flow velocity

The flow velocity through the pipeline is too low to hold the disc fully open against the disc's weight and spring (if fitted). The disc flutters at the partially open position.

2

Pulsating flow

Reciprocating pumps and compressors create pressure pulsations that repeatedly open and close the check valve disc at a frequency matching the pulsation.

3

Oversized check valve

A check valve sized for a larger flow than actually present will have insufficient velocity to lift the disc fully open, causing it to flutter in the low-lift zone.

4

Disc weight too high relative to flow

A full-open position requires a minimum upstream velocity. For swing check valves, the minimum recommended velocity depends on the angle of the hinge arm and disc weight. Check the manufacturer's minimum velocity table.

Safety Precautions

  • Chattering check valves can fatigue-crack pipe welds at the valve connections - inspect welds by UT if significant chattering has occurred
  • Full LOTO before internal inspection

Tools Required

  • Flow measurement device (ultrasonic clamp-on preferred for non-invasive measurement)
  • Vibration meter

Supplies Needed

  • Replacement disc and hinge pin (if damaged)
  • Dual-plate check valve (if design change required)
  • Spring kit (for spring-assisted designs)

Step-by-Step Repair Guide

  1. 1

    Measure actual flow velocity through the check valve

    Calculate or measure the actual liquid or gas velocity through the check valve bore at the operating flow rate. Compare to the manufacturer's minimum velocity for full disc lift (typically found in the valve datasheet or API 594 data). If actual velocity is below the minimum, the valve will chatter. A typical swing check valve requires 1.5–3.0 m/s liquid velocity for stable full-open operation.

    Flow velocity = Volumetric flow rate / Cross-sectional area of pipe bore. For an NPS 8" valve, bore area = pi/4 x (0.2027)^2 = 0.0323 m2.

  2. 2

    For pulsating flow: change to a nozzle or dual-plate check valve

    Spring-assisted dual-plate (wafer) check valves and nozzle check valves respond much faster to reverse flow than swing check valves. The spring force holds the disc at full open even at low velocities and snaps it closed at the first sign of flow reversal. Install a dual-plate check valve in the same face-to-face space as the swing check.

    Dual-plate check valves have a much shorter disc stroke than swing checks, so they respond to pulsations faster and do not chatter at the same velocities.

  3. 3

    Upsize the pipeline if undersized check valve is the root cause

    If the check valve is correctly sized for the pipe and chatter still occurs at normal flow, the piping itself may be oversized for the application flow rate. Consider installing a reduced-bore check valve or a smaller check valve with a reducing spool to increase velocity through the valve at normal flow.

  4. 4

    Inspect disc and hinge pin for damage

    After identifying and correcting the root cause, isolate and inspect the check valve internals. Hinge pins on swing check valves that have been chattering show characteristic peening (mushrooming of the pin ends) and the disc seating face shows impact craters. Replace disc and hinge pin if damaged. Continue to monitor after correction.

When to Replace Instead of Repair

Replace immediately if: the hinge pin is worn through, the disc has impact cracking, or the seating surface is so damaged that seat tightness cannot be achieved after disc replacement. Replace design type (swing to dual-plate) if flow profile is inherently pulsating.

Key Terms Explained

Unfamiliar with any terms used in this guide? Each links to a full engineering definition.

Check ValveCv (Flow Coefficient)Dual-Plate Check ValveNon-Return Valve (NRV)Swing Check Valve
Full valve glossary (113 terms)
For reference only. These guides are general engineering information intended to help maintenance teams understand common valve fault patterns. They do not replace site-specific procedures, manufacturer service instructions, or applicable codes and standards (ASME, API, IEC). Always work under a valid Permit-to-Work (PTW) with Lock-Out Tag-Out (LOTO) applied. Consult a qualified engineer before undertaking any maintenance on safety-critical, high-pressure, or hazardous-fluid systems. Vajra Industrial Solutions accepts no liability for actions taken based on this content.

Quick Reference

Difficulty
Moderate
Est. Time
2–4 hours to assess, 4–8 hours for design change
Steps
4
Category
Check Valves
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Steps

  1. 1Measure actual flow velocity through the check valve
  2. 2For pulsating flow: change to a nozzle or dual-plate check valve
  3. 3Upsize the pipeline if undersized check valve is the root cause
  4. 4Inspect disc and hinge pin for damage

More Check Valves Guides

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Key Terms

Full glossary (113 terms) →

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