Box clever

A small, dedicated logic box can be used to shut off power, compressed air, water or steam in response to detection of either the cessation of products passing down a production line, or the absence of workers. The Omnisava is the brainchild of a small Norfolk company, Watersavers, which according to director Stuart Richards has been manufacturing water saving controls for public conveniences since 1985. The new concept is intended to be universally useful as well as being inexpensive, simple and easy to set up and install. In addition, it has been supplying systems to a London based company that cut off compressed air to dry bottles and cans when receptacles are not detected, reducing air consumption by up to 30%, with a payback that Richards says is, 'well within a year'. As regards the Omnisava, he says: "I've had the idea for quite a while. I knew about saving water and compressed air, so came up with the idea of a product that would do everything. It's not cutting edge technology, but it puts together a combination of components that make it easy to understand, easy to apply, easy to install and easy to test." Inside the box, supplied by Spelsberg Els UK in Telford, is; a universal 100/240V AC to 24V DC power supply to power a solenoid valve or contactor, two chips which perform logic and timing functions; DIP switches and a timer adjustment control; traffic light leds to indicate power, sensor and valve status; and a test button. The timers are there either to delay actuation or turning off, as well as to regulate how long a valve should remain open. Externally, and available from the company, is either a compatible passive infrared sensor, or a suitable proximity detector. A typical application might be a workshop with an air compressor. Richards says: "No matter how good you are at fixing leaks, they will always happen." Hence a significant amount of air can be saved if, when the workers are sitting down taking a break, a passive infrared sensor detects a relative lack of movement and shuts off a valve attached to the compressor reservoir. Furthermore Richards says: "A burst hose fitting can be very costly in wasted energy if it occurs when the workshop is unoccupied." Similarly, in the food industry for example, water sprays, compressed air, vacuum or steam for heating may be turned off when items cease to come along the production line. Richards also mentions printed circuit board (PCB) production, where rinse cycles are maintained regardless of whether there are items to be rinsed. An array of nozzles on a production line can typically use 30scfm of compressed air, which equates to approximately 5kW or 50p/hour. Running continuously during two 12 hour shifts, five days per week, the nozzles would consume approximately £60 per week. By installing an Omnisava controller, valve and sensor costs around £270. A typical air saving of 30% will result in a payback of 15 weeks. Pointers * The universal, dedicated logic box economises the use of compressed air, vacuum, steam and electric power. * The unique nature of the device is that it is designed to be easy to supply, easy to wire, easy to understand and easy to test.