Stroke counters: measured delivery for accountable injection

1. What a stroke counter counts

A stroke counter is a simple mechanical device fitted to a sealant pump. It advances by one each time the pump completes a full stroke. The reading gives the crew a running total for the job.

What the counter records is strokes, not delivered volume. Delivery per stroke varies with the pump model, the hose and the sealant itself. Read the count against the stated output per stroke of your pump. Treat the result as a close estimate, not a measured fact.

Why count at all? A dose nobody counted cannot be repeated, defended or capped later. Auditors and clients ask a plain question: how much went in. A count is the start of an answer.

2. Counting by hand on a hand gun

A hydraulic hand gun, such as the BTR450D, has no counter. The operator counts strokes by hand, or notes the fall in sealant tins. Both methods work, and both demand attention.

Manual counting fails in the ways you would expect. Gloves, noise and a hard-pumping valve all pull attention away from the tally. Near the end of a long job, counts drift. A written tally on the job card helps, if someone keeps it current.

Some sites cross-check by weighing sealant tins before and after. That gives delivered mass, but it says nothing about which valve took what. Hand guns remain the least intrusive option for small, spread-out valve populations. For concentrated work, an air-operated gun takes over the pumping, which makes steady counting easier.

3. Pneumatic pumps with built-in counters

Pneumatic pump systems free both of the operator's hands. A mechanical counter can then watch every stroke without human attention. Our pneumatic pump systems come with customised stroke counters.

The trade-offs are real. A counter adds cost, and it is one more part that can fail or need servicing. Treat the reading as evidence to record, not as a control that stops the pump. A counter that reads wrong is worse than no counter, so check it during pump servicing.

For guns, minor and major service kits exist for each model. A tired gun delivers less per stroke than its stated output. The count then inherits that error. When weighing equipment options, start with our injection equipment buying guide.

4. Records that make injections accountable

The count earns its place in the written record. A job card with strokes, pressure response and product name stays readable years later. People who were not there can reconstruct the job.

A workable injection record holds at least these fields:

1. Valve tag, line service and date.
2. Product name, and cleaner used, if any.
3. Strokes counted, and the pressure response seen.
4. Operator name, and the stop condition reached.

With records like these, a successful job can be repeated with the same counted dose. How much sealant a valve needs stays uncertain, and quantity estimating guidance helps frame that uncertainty. The full visit sequence, with acceptance evidence, sits in our piece on the sealant injection visit. Annual maintenance contracts live on such records. A trend beats memory when a valve starts to pass.

5. Counted doses keep over-injection in check

Counted strokes cap the total amount a crew injects in one visit. That cap matters, because sealant forced past limits can pack cavities and change valve behaviour. The mechanisms are covered in our article on over-injection risks.

Injection itself carries conditions. The fittings must be in good condition, and the valve design must suit injection. Site permits must allow the work. Where OEM documents exist, read them for limits and warranty terms.

During the job, watch the pressure response and stop if it climbs sharply. The stroke count never proves the valve is sealed. The confirming step is a seat-leak test under agreed conditions, such as pressure decay across the closed valve. If leakage persists after controlled doses, the honest endpoint is a proper assessment, or replacement.