It is most important to prevent your Air Compressor from any breakdown,because breakdown not only increase maintenance cost but also suffers your production.You have to bear production loss due to breakdown of machine and engineeering troubles.
Many safety switches as like LOPS,LCWPS,HDATS etc. are installed for safety of compressor.
I have written on LOPS in last post.High Discharge Air Temperature Switch (HDATS) is also one of the most essential safety major has to be taken to prevent any abnormal to your valuable utility.If the temperature of discharge air (i.e.leaving compressed air from high pressure cylinder) is more,than the requirement,it could stuck the piston inside the cylinder,which cause a breakdown of compressor.
A working HDATS will safeguard your compressor from this problem.
A INDFOS Make RT-120 high discharge air temperature switch is normally used for safety of Air Compressor.We will see the details now.This switch having 2 mtr.long capillary connecting the switch and the bulb,with thermowell to fit the bulb.Fit the thermowell in air discharge line in the direction of discharge air flow in angular direction,in between the compressor and AFTER-COOLER,closer to the discharge cylinder.So the discharge air temperature safety can be done.If it has to monitor the air temperature before AFTER-COOLER.Fit the HDATS after the AFTER-COOLER,if it is to monitor the air temperature after AFTER-COOLER.
HDATS has to be set for some high value which is recommended by manufacturer that is why it is essential to set the temperature switch outside in an oil bath,having steady required temperature at the switch to be set.keep the differential setting at zero ,connect an Ohm meter across Normal close (NC)contact of the switch.Immerse the bulb and thermometer in the oil bath,keep stirring.
Set the high Discharge Air Temperature Switch at 170 degree Centigrade,on the main scale.control the steady temperature 170 degree Centigrade of oil bath,now close contact of switch should change & the Ohm meter pointer should show infinity,if not,reduce the setting till the contact changes to open.Increase the temperature setting if the contact opened before 170 degree Centigrade till it closes and opens.Now the switch is set at 170 degree Centigrade.
Confirm the setting once again by heating oil bath after the oil attains the ambient temperature or take fresh oil & continue the process.
After setting the switch,install near the thermowell,fill compressor oil in the thermowell and insert the bulb of temperature switch slowly.Wire the control cable in control pannel to Normal Close (NC) Contact of the switch.
Your Air compressor is more safe if you provide more safety devices.It is not possible to install all the safety due to cost or technical problem but still I recommend to install Low Oil Pressure Switch,Low water Pressure Switch,High Discharge Temperature Switch & Motor Overload Relay.
This four safety switches are most essential to run your Air Compressor without trouble.