Liquid level switches for lower temperatures
Magnetrol's new stainless steel Echotel 961 liquid level switch handles process temperatures down to -80 degrees C. It is made of standard 316/316L material with special potting material to handle the low temperature.
The standard 961 series offers a broad range of sensors including 316/316L, Hastelloy C, Monel, CPVC, Kynar and 316/316L with 0.5um sanitary finish.
Echotel 961 switches utilise pulsed ultrasound technology to detect the presence or absence of liquid. The system operates on a two-crystal pulsed or 'transmit-receive' principle that applies a 2MHz high-frequency electronic burst to the receiving crystal. The speed of propagation determines the absence or presence of liquid.
By applying pulsed wave technology, the unit is claimed to be less sensitive to buildup, aeration, foam and turbulence than most of its competitors. The 961 typically has a response time of <0.5s and is among the safest overfill preventions of its kind. With a SFF (safe failure fraction) of >90 per cent, it can easily be integrated in SIL 1,2 and 3 loops, depending on the user's safety system and historical experience with the technology.
A dual-point unit is also available with two selectable switch points on the same sensor (Echotel 962) for high and high/high level alarm, low and low/low level alarm or pump control.
The innovative features of the 961/962 include adjustable time delay, 'on-demand' test buttons for the output signal (alarm and error), LED indication for alarm status, reliability condition and, in case of malfunction, identification of the malfunction and separate error signal.
The 961/962 is designed for use in Atex intrinsically and explosion proof areas as well as CIP/SIP clean environments. The construction of the device conforms to PED (Pressure Equipment Directive) regulations.
Magnetrol's 961/962 is not sensitive to changing density or other liquid variables and therefore does not require any calibration. The units can be used on almost every liquid with a maximum viscosity of 10,000cP, resists temperatures from -80 up to +165 degrees C and pressures from full vacuum service up to 138bar. The 961/962 is also available with relay or current shift output.
"