When a cleaning contractor or plant maintenance team starts specifying steam equipment, boiler capacity and steam temperature usually get the conversation first. The water tank then receives far less attention, even though it decides how long a shift can run before someone stops to refill, where the machine is allowed to work, and how much plumbing has to be built around it. Comparing fixed and mobile options on tank capacity, water supply, and the logistics of refilling is a practical way to shortlist the right machine instead of over- or under-buying.
The tank sets the working rhythm of the job
A steam generator consumes water continuously while it is producing steam, so tank volume effectively equals uninterrupted working time. A small tank is not a fault; it is a design trade-off that keeps the machine light and compact, at the cost of a refill break. A large tank removes that break for a longer stretch, at the cost of weight and footprint. The honest question for an operator is simple: how many consecutive minutes of steaming does one typical task require, and is a refill interruption acceptable during that task?
Answering that requires looking at real work rather than catalogue numbers. An engine bay, a range hood, or a set of hospital bed frames each have a natural working duration. If a machine can finish that task on one tank fill, the crew moves from one job to the next without carrying hose and water across the site.
Fixed machines: capacity, and a permanent water point
A floor-standing unit gives room for a larger reservoir and a stronger heater. The fixed steam cleaning machine PowerDe HW02, for example, is listed with an 80 L SUS304 tank, 6 kW heating power, steam at about 160°C and vapor pressure around 0.8 MPa, in a cabinet of roughly 1,200 × 800 × 1,200 mm including handles, on a 220 V supply. That is a machine built for a place that has a water connection and a dedicated power outlet: the page also lists a tap-water inlet with a 4-point internal-tooth joint (1/2 inch), which assumes a plumbed supply rather than a jerrycan.
For operators this changes two decisions. First, a fixed tank plus a tap inlet means the machine can run essentially as long as the water supply allows, so very long tasks stop being limited by the reservoir. Second, the footprint and the 220 V connection mean the installation must be planned: a bay, a kiosk, a wash station, or a corner of a depot. Where a business already has that infrastructure, a fixed machine is usually the more productive choice. Where it does not, the plumbing and the wiring become part of the purchase price.
Protection functions matter more on a machine that runs unattended for long periods. The HW02 page lists leakage, short-circuit, high-temperature, high-voltage and water-shortage protection; the water-shortage cut-off in particular is what protects the heater when an operator does let a tank run dry.
Mobile machines: a smaller tank, but the job comes to the water
Mobile and hand-pushed units carry less water and gain reach. The hand-pushed medical equipment steam cleaning machine PowerDe HMW3 is listed with a 50 L clean-water tank, a 4.5 kW PTC semiconductor heater, dry- and wet-steam modes, and a 48 V battery supply, in a cabinet of about 1,150 × 520 × 1,030 mm that a person pushes by hand. The trade is explicit: a tank roughly two thirds the size of the fixed unit, but a machine that can be wheeled down a corridor, into a ward, or along a row of parking spaces.
The driving-style units go further in the same direction. The mobile steam cleaning machine PowerDe PWD02 and its related models (PWD01, HMW2) are described as active-water cleaning machines with dry-steam, wet-steam and hot-water modes, intended for indoor garages and narrow outdoor parking spaces, with battery versions listed alongside no-battery versions. Where a fixed machine needs a water point, these machines need a crew member who can fill them and, on battery versions, a place to charge. Neither requirement is a problem, but both need to be built into the working routine before the machine arrives.
How to compare, line by line
- Task duration versus tank size. Estimate the minutes of continuous steaming one job needs, then check whether a 50 L or an 80 L tank covers it. Refills that fall in the middle of a task cost more than the water.
- Water supply at the point of work. A tap inlet makes a fixed tank effectively unlimited. No tap means the crew carries water, which caps practical tank size regardless of what the machine can hold.
- Power at the point of work. A 220 V, 6 kW fixed unit needs an appropriate outlet and circuit. Battery-powered mobile units trade charging time for freedom from the cable.
- Movement between work points. Ward corridors, tight parking bays and multi-site service calls favour a hand-pushed or driving-style machine. One permanent wash bay favours a fixed cabinet.
- Water quality and tank material. A stainless steel tank such as the SUS304 tank on the HW02, plus the tap-water inlet specification published on the product page, is what an operator should check against local water hardness before assuming long service life.
Mixed fleets are common, and often correct
Many operators end up with both types: a fixed unit covering the base where the water and power already exist, and a mobile unit for work that is scattered, temporary, or in areas where a cable and a hose cannot reach. The deciding factor is rarely which tank is bigger. It is whether the machine will spend its life parked at one point or travel between points, and whether anyone is willing to plan the refilling and charging routine that mobility brings.
Shenzhen PowerDe Automation Precision Equipment Co., Ltd. builds both fixed and mobile steam equipment in Shenzhen and publishes tank volume, heater power and dimensions for the models listed above, which makes a like-for-like comparison possible before any enquiry. If your site has a water point and a 220 V supply, compare fixed models on tank volume and continuous working time. If your work moves, compare mobile models on tank volume against the distance between refill points. Where neither pattern fits, the customized steam cleaning equipment route on the site is the way to raise a mixed-fleet requirement with the manufacturer's engineering team.
