Bi-Directional Pressure Transducers For Vapor Recovery

• Bi-Directional pressure transducers are capable of measuring both positive and negative pressure ranges.
• Our industrial quality pressure transmitters are ideally fit for Vapor Recovery Units (VRUs), and they help reduce environmental impact by recycling hydrocarbon vapors that would otherwise vent or flare into the atmosphere.
• We offer both industrial style and hazardous area approved pressure sensors for vapor recovery applications including landfill gas recovery, digester gas recovery, casing-head pressure reduction, and more.

We offer a variety of high quality bi-directional pressure transducers for use in low pressure vapor recovery operations. Unlike a unidirectional pressure transducer that can measure pressures from zero to a defined positive pressure (i.e. 0 to 70mBar), bi-directional pressure transducers measure both positive and negative pressure (i.e. -70 mBar to +70 mBar).

Bi-Directional Pressure Transducers for Vapor Recovery

Bi-directional pressure transducers are commonly found in Vapor Recovery Units (VRUs) which monitor and recover light hydrocarbon vapors that collect at the top of oil and gas storage tanks. The positive end of the pressure transducers measurement range monitors the increase in vapor pressure at the top of the storage tank. In turn, the negative end of the measurement range monitors the suction when recovering the vapors from the tank. Recovering these vapors reduces the potential impact on the environment since they are not going to vent or flare. In addition, this presents financial savings for a company by converting the vapors into a liquid state which can then recycle back into the storage tanks.

Other applications to consider bi-directional pressure transducers include:

• landfill gas recovery
• digester gas recovery
• casing-head pressure reduction

Industrial Quality Pressure Transducers

Our pressure sensors utilize 316L SS wetted material in the manufacturing process to allow for a wide media compatibility. Custom configurations are available including a Hastelloy C276 diaphragm material for additional corrosion resistance.

Since bi-directional pressure transducers are very low pressure, it is important to follow proper venting techniques. Not venting the transducer properly can result in incorrect or inconsistent pressure readings. In addition, it can result in a reduction in lifespan of the equipment. Our pressure transmitters, from Core Sensors, use two different venting methods depending on the electrical termination choice:

• Transducers with cable connections have a vent tube that runs the length of the cable and exits the cable jacket with the rest of the conductors. Terminate the vent tube in a clean and dry area, preferably a weatherproof enclosure, to prevent moisture ingress.
• Transducers with connectors have a vent hole on or near the connector instead of a vent tube. However, the exact location of the vent hole depends on the electrical connector. Using a PTFE patch internally over the vent hole can help to prevent moisture ingress. Moreover, it is important to install the sensor in an area where minimal moisture will make contact with the sensors electrical connector.

Common Pressure Ranges

Recommended Bi-Directional Pressure Transmitters

For applications where hazardous area approvals are not necessary, we recommend the CS10 Industrial Pressure Transducer. The chart above shows a CS10 transducer with a ±70 mBar bi-directional pressure range, 4-20mA output signal, 1/4″ MNPT mechanical interface and a 1/2″ MNPT conduit fitting with integral cable. Visit the CS10 product page here for more information.

If hazardous location approvals are necessary, then we offer sensors with approval for:

• CSA Class I, Division 2 Non-Incendive
• CSA Class I, Division 1 Intrinsically Safe