Pump up the pressure
JUSTIN ROBERTS RUNS THE RULE OVER PRESSURE WASHER OPTIONS
IF cleanliness is next to godliness, then a pressure washer is one of the safer bets when it comes to achieving Nirvana. At the fundamental level, pressure washers instil energy into the water which is then expended in the removal of dirt.
Obviously, the greater the energy then the quicker dirt is removed and there are two main factors involved in imparting to the surface. The first is the pressure at which the water is ejected from the nozzle, while the second is the volume.
Achieving a high pressure with a pump is not a particularly expensive task; the cost is incurred in combining it with a high flow rate.
Increased water volume makes cleaning quicker and aids the removal of debris from the washing area.
Mobile or fixed
If the washer is intended to be used in one area, such as a workshop or cleaning zone, then wall mounted or other fixed units can save the bother of trying to store the pump unit and hose neatly. They also do away with electric cables and connections getting wet or run over.
Wall-mounted units may often be cheaper than mobile washers, but they do lack flexibility. For this reason mobile types dominate the market and there are a good variety of machines available.
Electric, engined or PTO.
Single phase plug in electric washers are probably the most popular on the market. They are relatively inexpensive, easy to set up, convenient to use and light to move around. However, they are also limited in volume and mobility, so may not be suitable for professional use.
Three phase electric models are available which can compete with engine powered units in performance levels. They may also support the use of two lances simultaneously, but the initial cost savings over petrol/diesel models, if any, are much less.
Powering the pump with an engine, either petrol or diesel, removes the need for a cable and so frees up the unit for use anywhere that an engine can be safely run. For entry level models, the cost is not necessarily much greater than commercial electric units. Although engine powered units do not require electric cables, cheaper models may not have a suction capability.
These will require water to be fed to them under pressure, usually a mains hose, thus limiting their versatility. Engine power can come via either a petrol or diesel engine. Petrol engines are lighter in weight and cheaper to build than diesels. They can also work at much smaller engine volumes meaning that lower power outputs are possible, further reducing costs. Diesel units start at around 8-10hp and cost in the region of €2,000.
Small petrol units are on sale from €300 for 3hp models. They may also be hand portable whereas diesels will require wheels or some heavy lifting to move around.
Diesel-powered units will often be geared up to drive the pump, reducing the revs and so saving running costs and wear and tear on the motor. Although offering plenty of performance they do not generally have a power off facility, so the engine, be it petrol or diesel, is running irrespective of whether the lance is in use.
A third route to powering a pump is by connecting it to the PTO of a tractor. This has the obvious advantage of not requiring an extra engine, but it can be something of an overkill.
Assuming that the average small yard tractor is pressed into service then just a few horsepower of the 70 or so available is actually being used.
Despite the inefficiencies of tractor-powered units, they come into their own for cleaning buildings and sheds where they may running almost continuously while in use. With no shortage of power on tap, their performance can match anything available with an independent engine at a much reduced purchase price.
Hot or cold?
Washing anything is greatly eased with the use of heat; it can enhance the mechanical effect of hitting the dirt with a water jet to a great extent.
Oil and grease is softened, the various salts and gums holding dirt together is easily dissolved and detergents work quicker at elevated temperatures. In a farm situation that heat is invariably produced by a diesel burning boiler.
Power for the pump is via a 240 or 400v supply and temperatures of up to 140deg C are possible. Engine powered units are available at a price, from around €6,000. Should both heat and mobility be required then purpose built separate hot water boilers may be the answer if your present washer can be used at high temperatures.
These are designed to supply heated water to a standard washer unit but will require a small generator to power the burner.