hi,
I am designing an oil heating and circulation sytem system for a gearbox. Heating comes from an immersion heater in a reservoir and need to monitor the temperature of the oil as it comes out of the gearbox. The system is simple and consits of a themocoule wired straight to PID controller which has a relay output to the immersion heater. the proble is that the pump of the sytem will not run on cold oil therefore i nedd to add a preheating circut, which also has to have a type of safety switch or control that will not overheat the oil in case its left unatended for a long period. would you be able to give any feedback on the following options or any other suggestions, i am araduate engineer with little experience so any comments would be helpful.
Option 1
Use a second themocouple on the reservoir and connnect the two thermocouples to a tc switchbox, which is manually fliped between the two tc's, and wire the output to the controller. cost swictch. Cost~ 60 £
Option 2
convert the tc signal into a 4-20ma through a temperature transmitter and use a swtich to flip between tc's.
for this i would need twa transmitters and the cost would be ~ 80 £
Option3
wire the second thermocouple to a second controller, costs 90 £, and manually switch between the two controller signals to the realy that gives the contact for the immersion heater.
Thank you for your time
I am designing an oil heating and circulation sytem system for a gearbox. Heating comes from an immersion heater in a reservoir and need to monitor the temperature of the oil as it comes out of the gearbox. The system is simple and consits of a themocoule wired straight to PID controller which has a relay output to the immersion heater. the proble is that the pump of the sytem will not run on cold oil therefore i nedd to add a preheating circut, which also has to have a type of safety switch or control that will not overheat the oil in case its left unatended for a long period. would you be able to give any feedback on the following options or any other suggestions, i am araduate engineer with little experience so any comments would be helpful.
Option 1
Use a second themocouple on the reservoir and connnect the two thermocouples to a tc switchbox, which is manually fliped between the two tc's, and wire the output to the controller. cost swictch. Cost~ 60 £
Option 2
convert the tc signal into a 4-20ma through a temperature transmitter and use a swtich to flip between tc's.
for this i would need twa transmitters and the cost would be ~ 80 £
Option3
wire the second thermocouple to a second controller, costs 90 £, and manually switch between the two controller signals to the realy that gives the contact for the immersion heater.
Thank you for your time
