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 In 2005 the popularity of telescopic poles to clean windows was increasing. The manufacturers of the water fed pole systems had turned to established 12VDC diaphragm pumps as used on agricultural spraying machines. Whilst these pumps delivered the water at the pressure required they did not allow the user to control the flow of the water which was essential for effective window cleaning. The remedy for the window cleaner was to throttle back the pump by putting a variable restriction in the discharge line. This had the desired effect at the brush and gave the flow control required, but unfortunately had the side effect of quickly destroying the pump's pressure switch and this in turn resulted in a perception that the pump was unreliable. An inexpensive hydraulic solution using a return to tank bypass and the balancing of two ball valves again achieved the desired flow at the brush by returning the rest of the water to the tank. However this solution was too time consuming to implement.
In the case of a window cleaner using a telescopic pole to clean windows of ground floor right up to the fifth floor the need was for instant flow control. Williamson Manufacturing recognised this problem and came up with a design that not only gave the user instant flow adjustment, but also compensated the pump flow according to the height of the pole. The concept of the Varistream was born and its widespread adoption in the water fed pole market both in the UK and overseas is a testament to its efficacy.
The Varistream was the first and remains the only pump controller on the market that adjusts the pumps flow according to the discharge pressure and this was its principle technological breakthrough, but hand in hand came remarkable improvement in pump reliability and a substantial increase in battery life. Approaching its third birthday, the Varistream remains the industry standard pump controller and has a bright future ahead as more and more window cleaners adopt water fed pole technology.
The latest version of the Varistream, used by many manufacturers of high quality water fed pole systems, is the Varistream Digital. Produced by Williamson Manufacturing Company Ltd for Williamson Pumps Ltd it can be purchased from our online shop or one of our distributers: Cleantech, Cleaning Spot, Pure Freedom, Sureclean, Varitech or Window Cleaning Warehouse. |
