When a factory measures cleaning water, what gets counted is usually not what the water bill shows. This guide sets out a metering method, a baseline, and a checklist that engineering and maintenance teams can apply to metalworking equipment cleaning.
In most machining shops, water used for cleaning equipment is billed as part of the general supply and never appears as a separate line. Maintenance teams are then asked to cut consumption and have no way to say where the volume goes, which machine drives it, or whether a change actually saved anything. Before any reduction can be verified, the measurement has to be defined: what is counted, over what period, and against what output.
Shenzhen PowerDe Automation Precision Equipment Co., Ltd. builds industrial steam cleaning equipment for factory and commercial use, and its engineers are asked this question during site surveys. The evaluation approach below reflects how they scope an equipment change; every figure your team records will differ, and the published specifications quoted here come from PowerDe's own product pages.
1. Define the boundary before you install a meter
A shop floor shares water between process cooling, parts washing, personnel facilities, and equipment cleaning. Installing one meter on the main supply tells you the plant total and nothing else. Define the cleaning boundary as the equipment you actually clean and the shift pattern in which cleaning occurs, then meter only those branches. Typical boundaries in a metalworking plant are:
- Machine enclosures, chips conveyors, coolant tanks and guard panels
- Transfer lines, fixtures, pallets and trolands used between operations
- Floors, drains and bunded areas inside the machining cell
- Downstream waste handling: oil-skimming units and swarf conveyors that are washed on a schedule
A plant that includes the wash cabinet in the cleaning boundary but excludes parts rinsing will produce a number that cannot be compared with a neighbour's plant. Write the boundary down and attach it to the meter log.
2. Meter per task, not per month
Monthly totals move with production volume and hide the cause. Record volume per cleaning task instead. For each task, log:
- Start and end time of the wash, and the number of machine positions or square metres covered
- Water meter reading, in litres, taken at the branch meter before and after the task
- Method and mode: high-pressure cold wash, hot-water wash, dry steam, wet steam
- Whether detergent was dosed, and at what concentration
- Operator and shift, so that technique variation becomes visible
Divide litres by machine positions cleaned, or by square metres of floor, and you have a unit rate that survives a change in production volume. Two weeks of this data on the existing method is enough to build a baseline. Without that baseline, any comparison of cleaning methods is an opinion.
3. What the flow rate of the equipment changes
Water consumption in equipment washing is mostly a function of flow rate multiplied by the time a lance or gun is open. A hose left running delivers far more volume per minute than a steam generator that turns water into vapour at the nozzle. A fixed high-pressure steam unit is rated by the water its tank and heater hold and consume, not by an open-hose rate.
The PowerDe HW02 steam cleaning machine is a fixed, 220 V unit listed at 6 kW heating power, 160 °C steam temperature, 0.8 MPa vapour pressure and an 80-litre SUS304 tank, with a tap-water inlet and switchable dry and wet steam modes. The figure your team should evaluate is not the tank size alone but the volume drawn from the supply during a full task, and that comes from your meter log, not from a specification sheet. Compare the HW02's measured litres-per-task against the litres-per-task of your current method over the same boundary.
A high-pressure steam cleaning machine is also a thermal decision. At the published 160 °C with 0.8 MPa pressure, steam supplies the heat that a hot-water wash needs to hold in a large volume of water. For oil and cutting-fluid residue on machine surfaces, heat does most of the work, and the water volume needed to carry that heat falls. Evaluate both effects together: litres per task and the labour hours needed to reach the same cleanliness.
4. Evaluate the wastewater, not only the intake
Water that leaves the wash contains coolant residue, swarf fines and oil. Its disposal cost often exceeds the cost of the intake, so a fair evaluation records both. Compare:
- Volume of effluent per task, and the oil content as measured by your current sampling routine
- Whether the effluent can pass an oil separator or skim unit at the reduced flow rate of a steam lance
- Detergent load, since a lower detergent dose reduces the treatment burden downstream
- Sludge and swarf handling, which changes when washing is done at a lower flow rate
Verify local discharge limits with your permit holder before treating reduced effluent volume as a saving. The arithmetic only holds under the conditions your permit sets.
5. Score the practical constraints of the site
A low water number that cannot be reached on your floor is not a saving. Score the following against the equipment you are considering:
- Power supply on site. The HW02 is listed at 220 V and 6 kW heating power; confirm what the bay can supply
- Water inlet type and quality. The HW02 inlet is tap water with a 4-point internal-tooth joint, 1/2 inch; scale load depends on your supply
- Footprint. The HW02 is listed at 1,200 × 800 × 1,200 mm including handles
- Mobility. Fixed units suit a set bay; the driving-style and hand-pushed units in the PowerDe cleaning range move to the machine instead
- Protection features and operator training requirements, as published on the product page
If the cleaning task moves between machines and there is no fixed bay, a mobile unit changes the labour side of the calculation even where the water saving is modest.
6. Run a one-cell trial before a plant decision
Choose one machining cell, clean it with the candidate equipment under your existing schedule, and log the same fields you used for the baseline. Compare litres per machine position, labour hours per task, cleanliness against your current acceptance standard, and effluent volume. A trial confined to one cell also exposes operator acceptance, which is where most cleaning projects fail.
PowerDe lists engineering services, including hardware testing and equipment customisation, alongside its cleaning range, so a plant that needs a non-standard configuration can raise it at the survey stage rather than after purchase. For a written comparison, ask the supplier for the specification sheet of the exact model, and confirm each figure against your own meter data before signing.
Evaluation checklist
| Check | Evidence to hold |
|---|---|
| Boundary defined | Written scope of machines, areas and schedules included |
| Baseline recorded | Two weeks of litres per machine position on the current method |
| Site constraints confirmed | Supply, inlet, footprint and mobility verified against the datasheet |
| Effluent costed | Discharge permit terms and separator capacity documented |
| Trial measured | One-cell log with water, labour and cleanliness results |
The question factories should be answering is not how much water cleaning uses in total, but how much each task uses per unit of equipment cleaned. Once that number exists, a change in method can be measured against it, and a reduction can be proven to whoever pays the water and effluent bills.
To survey a machining cell and check equipment suitability against your site conditions, contact Shenzhen PowerDe Automation Precision Equipment Co., Ltd. at sales@powerde.net, or review the cleaning range on the PowerDe cleaning equipment series page.
