Pressure Transmitters for Heat Meters

Pressure transmitters are integral to heat meters installed into heating systems with the load of 0.5 Gcal/h and more, used at residential properties and industrial facilities. "Energy Saving and Energy Efficiency Improvement up to Year 2020" government program prescribes installing slightly less than 2.5 million collective heat meters, i.e. those that register consumption of the entire residential property.

GOST R 51649-2000 "Heat Meters for Water Heating Systems. General Specifications" and "Heat Energy and Heat Medium Registration Rules" (approved by the Ministry of Fuel and Energy of the Russian Federation on September 12, 1995, #Vk-4936) contain requirements for heat metering equipment.

As part of a heat meter, a pressure transmitter allows using the average hourly pressure values to correct the registered heat medium volume. The device must comply with GOST 26.011-80. Vortex, electromagnetic and ultrasonic heat meters typically come with a pressure transmitter.

Industrial-grade and residential property heat meters feature inexpensive and reliable pressure transmitters. An important factor to consider when picking a transmitter is its calibration interval.

Design Features of Pressure Transmitters for Heat Meters

The generally used electrical connection is DIN 43650, pressure port -- M20x1.5. The output signal is 4 ... 20 mA. The pressure ranges are from 0 ... 6 to 0 ... 25, gauge pressure, accuracy -- 0.5% of span.

Pressure Transmitters for Heat Meters by BD SENSORS RUS

When it comes to pressure transmitters in heat meters, it is either the manufacturer of the heat meter that installs them or the mounters that do that following recommendations provided by the manufacturer. These recommendations, the list of transmitters to complete the heat meter, come as an annex to the metering device approval certificate.

Heat meters accepting pressure transmitters by BD Sensors RUS

Vortex heat meters utilize a well-known natural phenomenon, formation of vortices behind an obstacle standing in the path of the flow. When the medium velocity exceeds a certain limit, the vortices line up into a regular path called the Carnot path. Disruptive flow of fluid in a pipeline results in pressure pulsations; measuring them allows registering the volumes of liquid going through the pipeline. The frequency of vortex formation is directly proportional to the flow velocity.

Flowing through a magnetic field, liquids generate electric current; this is the phenomenon enabling registering volumes with electromagnetic heat meters. Such meters calculate thermal capacity and heat energy using the flow volume and heat medium volume data, as well as temperatures in feeding and return pipelines corrected by changes in heat capacity of the heat medium (difference of in and out temperatures).

Ultrasonic heat meters measure the time it takes an ultrasound signal to go from the transmitter to the receiver; this time is directly proportional to the fluid's velocity in the pipeline.