This plant bottles drinking water for retailers across three provinces, holds strict hygiene standards, and fogs around the building weekly under a schedule set by its auditors.

The site has a wastewater treatment pond and drainage channels that breed mosquitoes year-round, so fogging is not a seasonal activity here — it is a weekly routine.

The plant's fogger therefore works far harder than most, and when a machine works hard, small problems that other sites overlook show up clearly and quickly.

The day the flow slowed and someone proposed a shortcut

After about eight months of use, staff noticed the solution was flowing more slowly and each round was taking longer to cover the same area — time that should have gone to other work.

The maintenance supervisor removed the solution delivery assembly and found a small strainer at the pickup inlet, so coated with residue and sediment that the mesh was barely visible.

His conclusion was straightforward and wrong. He saw the strainer as an obstruction. Removing it made the solution flow freely again immediately, so the problem appeared solved.

The correct action was to clean the strainer, refit it, and find out why there was so much sediment. But removing it produced an instant, tangible improvement, so that is what got chosen.

The first two months, when things really did seem better

With the strainer gone, solution flowed freely, each round took nearly twenty minutes less, and staff were pleased. Nobody had any reason to question the decision.

What was invisible was that everything the strainer used to catch now travelled freely into the system: sediment from the bottom of the tank, label fragments from solution containers, and crystals that precipitate naturally out of the product.

Most of these particles are smaller than the nozzle orifice and passed straight through at first, but some accumulated where passages narrow and in the grooves of the valve assembly.

Month three was the first nozzle blockage. The plant stripped and cleaned it themselves and carried on, treating it as a one-off — an understandable reading that let the problem continue for months more.

A blockage cycle that consumed time and parts

From month four on, the nozzle blocked roughly twice a month. Each incident meant about forty minutes to strip and clean, and one occasion pushed the fogging schedule back by two days.

The frequent stripping caused damage of its own. Every disassembly wears the seals and O-rings a little more, and on two occasions a fitting was overtightened and the thread damaged.

Staff started clearing the orifice with a wire because it was faster than a full strip-down. That deformed the orifice edge and permanently changed droplet size, so fog quality declined even on days when nothing blocked.

By month seven the solution pump had developed an abnormal noise and an unstable delivery rate — the point at which the plant called us instead of repairing it themselves again.

What we found when the delivery system came apart

Our first question was whether the strainer was still fitted. The answer — no — explained seven months of symptoms in a single sentence.

Inside the pump housing were scoring marks from hard particles that had passed through, and the pump seals had worn unevenly enough to make the delivery rate fluctuate. That is precisely the damage the strainer exists to prevent.

The nozzle orifice edge was deformed from repeated wire probing. Measured droplet size was significantly larger than specification and unevenly distributed.

The solution tank held about three millimetres of sediment on the bottom — the source of every particle, and the sign that the real problem all along was not the strainer but inadequate tank cleaning.

10 reasons customers choose World Health Disinfection

1. We look for the missing part first

On a machine that blocks repeatedly, our first question is whether the strainer is still fitted, because it is the most common and most overlooked cause.

2. Tank cleaned and the sediment source identified

We do not clean the tank and stop there. We determine whether sediment comes from mixing, from the water used, or from storage, and address it at source.

3. Pump and seals inspected after use without a strainer

Particles that get through always damage the pump. We inspect the housing and seals every time, so the customer does not return with a fluctuating delivery rate.

4. Droplet size measured to assess the nozzle

A previously probed nozzle produces incorrect droplet size. We measure before deciding whether it can be kept or must be replaced.

5. Strainer refitted with a cleaning interval

We do not just refit it — we set a clear cleaning interval and show staff how to do it themselves in a few minutes.

6. Manufacturer-specification parts only

Strainer, seals and nozzle must match the model. A wrong mesh size makes the whole system behave differently from its design.

7. Delivery rate verified by real measurement

After repair we measure delivery rate by timing and weighing and record it on the job sheet for the customer's file.

8. Tested with the customer's own solution

We test with the product the plant actually uses, to confirm there is no repeat blockage under real operating conditions.

9. Service that understands factory requirements

We understand that food and beverage plants have audit obligations, so we hand over documentation suitable for a maintenance file.

10. Nationwide pickup and return

We collect from and return to factories, warehouses, hotels, schools, farms and local authorities across Thailand.

What the solution strainer does and why it must stay

The solution strainer sits at the pickup inlet inside the tank and catches particles larger than the nozzle orifice — sediment from the tank bottom, label fragments, rubber debris and crystals precipitated from the product.

Nozzle orifices in fogging machines are very small. Particles barely visible to the naked eye are enough to skew the spray direction or block it entirely.

More importantly, the strainer protects the pump. A solution pump has moving parts with very precise clearances; hard particles that get through score the surfaces and wear the seals permanently.

When the strainer clogs, what it is reporting is unusual sediment. The fix is to clean it and find the source — never to remove it, which means taking the protection out of the system.

Reducing tank sediment at source

Always mix solution in a separate container before pouring it into the tank. Mixing directly in the tank lets undissolved material settle straight to the bottom and get drawn in on the next round.

Pour the mixed solution through a filter cloth or filter funnel into the tank. That adds under a minute and massively reduces the load on the strainer.

Always mix with clean water. Groundwater or mains water carrying suspended solids is a sediment source many plants overlook. If the water carries sediment, settle or filter it first.

Rinse the tank with clean water after every use and clean it thoroughly at least monthly. Leaving solution standing in the tank is the number one cause of sediment on the bottom.

Frequently asked questions

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