Wherever marginal gas pressures or liquid levels have to be determined quickly and positively, purely mechanical, membrane-controlled pressure switches are an economical sensing and switching solution. Built onto a dip tube, minimum and maximum levels can thus be detected rapidly and valves or pumps switched off and on or alarms triggered depending on the liquid level. Because the pressure gauge does not come in contact with the medium, this method of measurement is suitable for measuring liquid levels in the foodstuffs industry and beverage sector but it also tolerates slurries in industrial overflow basins or waste water treatment. More exact switching points at low liquid levels are also increasingly being demanded. To this end,
The pressure switch 901XL (Fig.) offers a permanently set trip pressure from 3 mbar up to 50 mbar which is supplied factory set to the desired value. This means it can even detect lowest gas pressures or liquid levels respectively from approx. 3 cm hydrostatic head. The standard switching differential of 1.5 mbar at the start of the range and 15 mbar at the end of the range with a switch point tolerance band of 10 %. The new pressure switch is equipped with a larger membrane area for this which reliably actuates the switch contacts even at the slightest pressures. This can switch with a resistive load up to 6 A / 240 VAC in AgNi execution or in the low voltage range up to 100 mA / 24 VAC or 30 mA / VDC in gold plated execution. Special designs are possible in AgNi up to 10 A / 240 VAC.