PWHT EQUIPMENT CONNECTION
Below is the connection diagram of PWHT equipments.
1. Control panel and Proportional Integral Derivative (PID) controller: Control panel receives the power input from the mains. ELCB/Fuse, over current protection system etc will be in the control panel.
PID controller need power for working the same which will be taken from control panel. The PID controller contains PID's which can be programmed as per the requirement of PWHT cycle.
1. Control panel and Proportional Integral Derivative (PID) controller: Control panel receives the power input from the mains. ELCB/Fuse, over current protection system etc will be in the control panel.
PID controller need power for working the same which will be taken from control panel. The PID controller contains PID's which can be programmed as per the requirement of PWHT cycle.
Then PID controller takes the input's as follows:
Temperature up to soaking temperature.
Time for reaching up to soaking temperature(rate of heating)
Soaking temperature
Time for soaking.
Temperature up to controlled cooling
Time to reach that temperature (Rate of cooling)
Temperature up to soaking temperature.
Time for reaching up to soaking temperature(rate of heating)
Soaking temperature
Time for soaking.
Temperature up to controlled cooling
Time to reach that temperature (Rate of cooling)
2. Temperature recorder:
Temperature recorder records the temperature against time. This will be recorded against each thermocouple and each graph corresponding to be each thermocouple will be of different colour. The temperature recorder is working on the principle of potentiometer
3. Thermocouples:
Thermocouples detects the temperature as voltages based on the seebeck effect or thermoelectric effect. These voltages are used by PID controller to control the temperature and temperature recorder for recording it.
4. Thermocouple extension wires:
Thermocouple extension wires are used to connect the thermocouple to the PID controller and temperature recorder.
5. Coils:
Coils heat the joints by resistance heating method.
6.Power cables:
Power cables are used for connection between PID controller&Control Panel to the coiles for power transmission.
Temperature recorder records the temperature against time. This will be recorded against each thermocouple and each graph corresponding to be each thermocouple will be of different colour. The temperature recorder is working on the principle of potentiometer
3. Thermocouples:
Thermocouples detects the temperature as voltages based on the seebeck effect or thermoelectric effect. These voltages are used by PID controller to control the temperature and temperature recorder for recording it.
4. Thermocouple extension wires:
Thermocouple extension wires are used to connect the thermocouple to the PID controller and temperature recorder.
5. Coils:
Coils heat the joints by resistance heating method.
6.Power cables:
Power cables are used for connection between PID controller&Control Panel to the coiles for power transmission.
Refer the connection diagram.
The coils are heated thereby temperature is developed through resistance heating. The current required to the coils are given by control panel through PID controller. The PID controller detects the temperature of the Job through the thermocouple connected to the PID controller and decides whether the current to be allowed to flow through the coils or not. This on and off of current flow through the coil by the feedback of thermocouple helps the process to generate a controlled temperature cycle.
The coils are heated thereby temperature is developed through resistance heating. The current required to the coils are given by control panel through PID controller. The PID controller detects the temperature of the Job through the thermocouple connected to the PID controller and decides whether the current to be allowed to flow through the coils or not. This on and off of current flow through the coil by the feedback of thermocouple helps the process to generate a controlled temperature cycle.
One coil can be used to connect more than one joint depends in the length of the coil (the length of the coil is decided by the current load.)
Suppose 2 joints are connected by a coil. One thermocouple from any one joint will be used to control the temperature and is called controlling thermocouple. This thermocouple will be taken from the joint and will be connected to the PID controller and from PID controller it is connected to the temperature recorder.
All other thermocouples from both the joints ( on the assumption that two joints are connected using a coil) are directly connected to the temperature recorder.
One temperature recorder can detect temperature from 6 points in a 6 point recorder (most common) and temperature 12 points in a 12 point recorder.
A PID controller contains 3 PID's (most common design) which will control 3 different coils connected from the PID controller.
THANX
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