The importance of the torque switches on scrapers installations
posted in Technical Articles by TecnoConverting
In scrapers installations for sludge removal, both circular and rectangular, it´s very important to incorporate a torque switch to protect the equipment from damage and downtime.
The torque switch is a component of the scraper that is installed on the control panel to prevent from possible damage due to mechanical over strength.
The function of the torque switch is to constantly monitor the rated current consumed by the electric motor, and when the equipment exceeds the value previously set, it automatically switches off the engine of the scraper.
A sludge scraper, either circular or rectangular, does not have work improperly if the maintenance is correct. But the truth is that sometimes these equipments can suffer damages.
The most common breakage is that the scraper remains engaged due to an object trapped between the sludge blades. This object is an impediment to the normal rotation of the scraper, forcing the equipment to an extra effort. If this is a minor overexertion, there will be no problem, but if the object is large enough, and in consequence also the over strength, it could cause a malfunction in some components of the scraper: blades, shaft, reducer, electric motor, etc.
In this case the torque switch would act, as the rated current consumed by the motor would exceed the preset value, and therefore it would electrically disconnect avoiding any problem or something worse. In addition, the torque switch warns the user with a sign in order to solve the problem before switch on again the srapper.
It can also occur an overcharge to the scraper if it has been empty and off for a long time, so in this case existing sludge could solidify and the rotation of the scraper may be very difficult.
In this case if we switch on the scrapper again, the torque switch acts in the same way.
If there’s no torque switch on control panel, the scraper may end up breaking, not only causing problems on the equipments, but also full of damage to the entire installation: lamellas, under support structure, etc. Turning in a big problem for plant user.
In some works we have seen that scraper’s breakdown were caused for an excessive sludge accumulation in the settler.
If the operator doesn’t realize it, the sludge can reach to the top of the lamellar modules, and in the event that the support structure is not properly sized, it may collapse causing the lamellas sink to the bottom of the tank.
In conclusion, it is vital to incorporate a torque switch in all installations with mechanical equipment such as scrapers, to detect any over-intensity at time and stop the equipment before, it can cause further damage to the equipment and installation.