Quiet the Shake – Smoothing Out Lines with Pulsation Control

If your chemical lines chatter, gauges flutter, or injection points “spit”, you are seeing normal side effects of positive-displacement dosing. Metering pumps move fluid in tiny gulps, not as a smooth stream. The fix isn’t to crank down a valve. It’s to tame pulsation so the system runs calm and accurate.

Here’s a plain-speak guide to why lines shake, what to add, and how to set it up right.

Why Metering Lines Rattle

• The pump doses in strokes. Each stroke sends a pressure wave into the pipe.
• The wave hits tees, elbows, and check valves. It bounces back and forth.
• The result is vibration, gauge flicker, and noisy injection.
• On long or small-ID lines, the problem gets worse. Friction and trapped air exaggerate the pulses.

What Problems Pulsation Causes

• Unstable dose at the injection point.
• Premature wear on check valves, gauges, and fittings.
• Nuisance low-flow alarms because the flow switch can’t decide.
• Air pockets that refuse to purge.
• Operator “fixes” like throttling a valve, which only wastes energy and hurts accuracy.

The Core Toolkit to Calm the System

Pulsation dampener (discharge side).

A small pressure vessel with a bladder or gas charge. It soaks up the pressure spike and releases it between strokes. Think shock absorber for your pump.

Back-pressure valve.

Adds a steady minimum pressure so the pump’s check valves seal every time. It stops siphoning on downhill runs and steadies flow on short lines.

Relief valve.

Protects the pump head and tubing if a valve is closed or a line plugs. Set it a little higher than normal discharge pressure.

Larger ID or shorter tubing.

Bigger, straighter, shorter runs reduce friction, so pulses fade faster. Gentle bends beat tight elbows every time.

Good suction-side practice.

A foot valve/strainer, straight shot to the pump, and a degassing head for gassy chemicals (like bleach) keep the pump from “gulping” air.

A 10-Minute Setup and Check

1. Depressurize the line. Verify the dampener pre-charge with a handheld gauge.
2. Confirm relief valve setting with a tag or bench test.
3. Set the back-pressure valve as above.
4. Start the pump at normal stroke and speed.
5. Watch the discharge gauge. If it still flickers, bump the pre-charge up a few psi, then down a few psi, to find the smooth spot.
6. If flutter persists, increase dampener volume or go up a tubing size.

Common mistakes to avoid

• Mounting the dampener far from the pump or on a branch leg.
• Putting the back-pressure valve ahead of the dampener.
• Running with zero back pressure into an open tank.
• Neglecting pre-charge checks – an empty dampener is just a pipe tee.
• Using tiny, long, coiled tubing “because it was handy.”

When to call for help

• You need very low pulsation for a flow meter or pH control loop.
• The chemical is hot, gaseous, or highly viscous.
• The line is hundreds of feet long or climbs several stories.
• You’re mixing accessories across brands and want to be sure the materials and ratings match.

Tuned pulsation control gives you quieter lines, steadier numbers, and more accurate dosing. That means better process results, longer component life, and fewer nuisance alarms.

If you’d like a quick review of your metering pump setup, we can help size and place pulsation dampeners, back-pressure and relief valves, and get your injection quill and tubing sorted. Call Vissers Sales Corp. at 1-800-367-4180 or visit our industrial pump systems to get started.

A calm line is a reliable line.