Choosing a Dosing Pump for Commercial Dishwashers and Laundries

In commercial dishwashing and laundry operations, chemical consumption is the cost item that slips out of control fastest. When detergent and rinse aid are added by hand or by eye, you either waste chemical or fall short on cleaning and hygiene. A dosing pump guarantees the same amount in every cycle.

Hotels, hospitals, catering plants and restaurant chains process hundreds of racks and tonnes of linen a day. At that volume even a 10–20 percent saving in chemical adds up to a serious budget difference by year end. Repeatable dosing also keeps hygiene records consistent for audits.

Pump selection depends on machine type, chemical viscosity, wash programme and control requirement. Chosen correctly, the pump works invisibly in the background; chosen poorly, blockages, air-locking and burst tubing become recurring complaints.

A dishwasher uses two core chemicals: an alkaline detergent fed into the wash tank and a rinse aid fed into the final rinse water. Detergent is liquid and often viscous, and its concentration is regulated against wash tank conductivity. Rinse aid is dosed in very small, constant amounts on every rinse cycle.

The two tasks need different flow rates and different control logic. The detergent pump typically runs at a few litres per hour and starts when tank conductivity drops. The rinse aid pump is triggered by the rinse signal and delivers short doses lasting seconds. Most professional systems therefore use two separate pumps or a two-channel dosing unit.

Laundries are more complex still: main detergent, bleach (hypochlorite or peracetic acid), softener, neutraliser and sometimes an enzyme product, 4–8 chemicals in total, dosed in sequence according to the programme step. Laundry dosing systems are therefore multi-channel and read the machine's programme signals.

Peristaltic (tube) pumps are the most common technology in HoReCa and laundry dosing. The chemical only touches the tube, the pump is self-priming and it never air-locks with viscous detergents or gassing hypochlorite. The tube is a consumable replaced periodically, a simplicity that is a real advantage in a kitchen environment.

Solenoid diaphragm pumps, covering 0.4–110 L/h at 1–20 bar back pressure, are preferred where dosing goes into a pressurised line. In the central chemical line of a flight-type dishwasher, or when a laundry doses from a remote central tank through a pressurised pipe, a solenoid pump runs more steadily. With low-viscosity, non-gassing chemicals it has a long service life.

The decision weighs viscosity, gassing tendency, back pressure and daily running hours together. Because Vanera offers both the SEKO Kronos peristaltic series and the Tekna and Invikta solenoid families, we can recommend on merit rather than push a single technology.

Detergent concentration in a wash tank cannot be measured directly, but alkaline detergent raises the electrical conductivity of the solution (µS/cm or mS/cm), which makes conductivity a reliable proxy. A conductivity-controlled dosing unit measures with a probe in the tank and starts the detergent pump when the reading drops below set point.

Compared with timer-based dosing, the benefit is significant: concentration stays constant even as fresh water intake, rack count or soil load changes. The result is lower detergent use and the same cleaning performance in every wash. The set point is adjusted at commissioning to the concentration range recommended by the detergent manufacturer.

If probe cleaning and calibration are neglected, scale and grease build-up lowers the reading and the pump overdoses. Adding a probe check to the maintenance plan is the simplest way to protect the economics of a conductivity-controlled system. In laundries, control is usually driven by relay or volt-free signals from the machine programme.

In hospitals, care homes and food production kitchens, dishwashing is one of the critical control points in the HACCP plan. Auditors expect wash temperature, rinse temperature and chemical concentration to be recorded. For commercial dishwashers, European hygiene performance standards such as EN 17735 and the German DIN 10512 are the usual references, and chemical dosing is a precondition for meeting them.

In laundries, and especially for hospital textiles, thermal or chemo-thermal disinfection procedures apply. Bleach and disinfectant doses must be sufficient yet not damage the textile; sequenced, measured dosing delivers that balance. Advanced dosing units log cycle counts and consumption, simplifying the audit report.

Another hygiene point is connecting chemical containers to the pump as a closed system. Operator contact with concentrated chemical is reduced, occupational safety requirements are met and the risk of mixing up containers falls. Colour-coded suction lances and level switches complete the closed system.

In restaurant and cafe kitchens the priority is compactness and ease of use. For undercounter and hood-type machines, a two-channel (detergent plus rinse aid) peristaltic unit, integrated or wall-mounted, is usually sufficient. With high staff turnover, lockable settings matter.

In hospitals and care institutions, disinfection safety, logging and alarm functions come first. Systems that can stop the dishwasher when chemical runs out, multi-channel laundry dosing tied to programme steps and consumption reports are expected. Resistance of wetted parts to heavy alkalis and chlorinated products is decisive in this sector.

In hotels the dish room and laundry usually fall under the same technical team, so systems from one brand with a common spare parts and service approach make operation easier. Flight-type dishwashers and 50–100 kg washer-extractors raise flow requirements, and here solenoid or motor-driven diaphragm pumps are considered alongside peristaltic units.

The price of a dishwasher or laundry dosing system depends on channel count (1, 2 or multi-channel), pump technology (peristaltic or solenoid), control method (timer, conductivity probe, machine signal), display and logging functions, and the scope of tubing and suction accessories. Two quotes that look alike may differ simply because one omits the probe or level switch.

Over the life cycle, tube replacement interval, probe life and spare part availability matter as much as the initial investment. Closed systems tied to a chemical supplier may look cheap up front but are paid back through the chemical price. A brand-independent system backed by an authorised dealer leaves the operator free to choose its chemical supplier.

When requesting a quote, share the machine type and model (undercounter, hood, flight; washer capacity in kg), the chemicals used and their viscosities, the dosing point (tank or pressurised line), the control method required and the daily cycle count. With this, channel count, pump type and control unit can be configured correctly.

Vanera Engineering, an authorised SEKO dealer based in Umraniye, Istanbul, supplies peristaltic and solenoid dosing pumps, conductivity control units and accessory kits for HoReCa, hospital, hotel and industrial laundry projects, with configuration and commissioning support from a single restaurant kitchen to a multi-site hotel chain.

To find the right dosing solution and total cost for your dish room or laundry, send your machine and chemical details through the Quick Quote form and our engineering team will return a channel count and pump type recommendation.