High temperature pressure transmitters with a 4-20mA output, tolerant to high temperature applications such as steam, food processing & engine monitoring.
High temperature pressure transmitters are used in applications where the media temperature exceeds the temperature limits of standard pressure transmitters or where it is not possible to fit a stand off pipe, pigtail or other cooling device to reduce the media temperature.
- DS201P High Range Flush Pressure Gauge, Switch and Sensor
- DS200P Sanitary Low Range Pressure Gauge, Switch and Sensor
- DMP331P Hygienic Flush Pressure Transmitter
- ATM/T Pressure and Temperature Dual Output Transmitter
- DMK331P Flush Diaphragm Pressure Sensor
- 35X HTC High Temperature Digital Pressure Sensor (< 300 degC)
- 35X HTT High Temperature Compensated Pressure Sensor
Specifying pressure transmitters for high temperature use
What will be the maximum process temperature reached in your application?
The sensor technology utilised in pressure transmitter has an operating temperature range which is adequate for most applications, but there are some which will require additional components to protect the sensor from heat damage.
Typically the design approach is to reduce the temperature in the vicinity of the pressure transmitter by incorporating a mechanical cooling assembly to dissipate the heat.
The cooling assembly maybe filled with oil and separated from the process media by an isolation diaphragm.
Alternatively the cooling assembly can include hollow tubing shaped to increase heat transfer, which causes the process media allowed through, to reduce to a much lower temperature.
The choices of cooling mechanism fall into the following categories:
Add-on cooling adaptor
Add-on compact process media filled cooling adaptor with coiled capillary, hollow discs or fins for increasing surface area to act as heat sink for medium temperature protection.
Integral cooling element
Integral oil-filled isolation diaphragm seal shaped to increase surface area between sensor and isolation diaphragm to increase efficiency of cooling and provide for high temperature protection.
Capillary tube cooling
Integral oil, mercury or other fluid filled capillary with a long length and small diameter for extra cooling in very high temperature processes.
What will be the range of temperatures surrounding the pressure transmitter where it is installed?
This is an important consideration when dealing with high temperature processes or surrounding environments.
In applications where the process temperature is high, it is possible to use a pressure transmitter with a built-in cooling mechanism. This cooling mechanism often relies on the conduction and dissipation of heat to the surrounding air around the pressure transmitter. Therefore it is essential the ambient air temperature is lower than the process temperature. Also since the rest of the pressure transmitter connected to the cooling component is not protected from high temperatures, the ambient temperature should be lower than the device operating temperature range. This will ensure an efficient heat sink and protect the electronic components from thermal damage.
When it is not possible to install the pressure transmitter in a lower temperature environment, it is then necessary to use one that is completely protected from high ambient or process temperatures. These types of high temperature pressure transmitters do not need any cooling mechanism, and all components including the sensing technology, conditioning electronics, solder, adhesives, connectors and cables are rated to the maximum operating temperature.
Checklist for high temperature pressure transmitter requirements
Define your high temperature pressure transmitter requirements using this checklist:
- Process temperature?
- Cooling mechanism?
- Ambient temperature?
- Pressure range?
- Output signal? 4-20mA
- Electrical connection?
- Process connection?
- Process media type?