K-TEK, a large manufacturer of level detection gauges is offering its Model KP bin level indicator - a robust paddle switch with some good features.
Its makers say that the KP bin level indicator offers the industry's first screw-off cover for easy accessibility during installation and maintenance. "Most other paddle switches have bolts, so when it comes to time to take the cover off and wire the switch or replace the motor, the technician has to remove six bolts and try to find a place to put them while he is 40 feet up in the air - which is often the case," notes Rick Ayers, K-TEK sales manager. "Invariably, he will drop one of the bolts onto the floor. But with the KP Model, it is a real plus because it is easier for the tech to get to."
The KP bin level indicator makes use of a low speed (1 r.p.m.) low torque, synchronous motor that always stays energised to eliminate moisture build-up. Other paddle switches that stop and start allow condensation to accumulate after the motor cools. "The trouble with condensation that builds up in a carbon steel housing or an aluminium housing, is that it causes corrosion," notes Ayers. "When the material level drops and the paddle is supposed to turn, the paddle will not budge and the gears wear out. The process then grinds to a halt while the tech climbs up onto the silo to service older generation switches."
The hysteresis motor of the KP bin level indicator allows it to run in a restricted or completely stalled state without damage or overheating. A safety clutch further protects motor gearing (metal) by absorbing sudden shocks. When the unit eventually senses the presence of dry material via the restricted motion of the paddle, the reversing torque actuates one or two internal SPDT (single pole, double throw) switches that can control up to two operations, such as sounding an alarm or shutting off a conveyor belt or feeder. AC switch ratings approach 20 A resistive (746 W @ 120 V a.c. or 1,5 kW @ 250 V a.c.). DC feeds rate at 0,5 A, 125 V d.c. 0,25 A, 250 V d.c. One switch can activate a built-in indicator light on the outside of the housing to provide visual confirmation of bin 'state/status' from the plant floor.
To accommodate a wide range of applications, the KP bin level indicator demonstrates flexibility in mounting configurations-offering both vertical or horizontal positioning - via an industry standard mounting plate of 304 SS; flexible shaft couplings; and shaft extensions and guards up to 7,6 m.
Drop in replacement of existing roto-paddle switches is facilitated by a wide variety of KP bin level paddles for different product densities ranging from 160 kg/m3, to 1200 kg/m3 (coal), on up to 1680 kg/m3 (for foundry sand). Harsh environments are managed by way of non-contact, double shielded bearings; shaft lip seal rated to 970 kPa; and operating temperatures of -40 to 120°C. A choice of 120 or 240 V a.c. operating voltages permits additional retrofitting possibilities.
The KP bin level indicator is immediately available with a range of options - such as explosion-proof housing (FM approval pending) to meet the needs of reliably measuring and controlling bulk solids. "When it comes to handling dry level, paddle switches are the standard," says Ayers. "You cannot beat them because they are mechanical, straightforward, easy to install; and with the introduction the KP bin level indicator, they are now inexpensive."
For more information contact Blanes Instruments, 011 425 1465, [email protected], www.blanes.co.za
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