Pressure Transmitter suppliers and Types

Effective Solutions for Liquid and Solid Monitoring

Before considering pressure transmitters, we ought to look at some historical facts that come into play. In the early 20^th century, it was far more common to see installations of pressure gages vs a pressure transmitters.

What is a Pressure Gauge?

Pressure Gages are often considered to be products that use pressure to effect a mechanical piece (e.g Bourdon tube) which will indicate the pressure inside a closed system by the use of a visual pointer. These pressure gages are fabricated in different models which are designed to indicate pressure in different media of different pressure ranges and temperatures. Oftentimes where chemicals affect wetted parts, a diaphragm seal is used to isolate the gauge from the media.

What is a Pressure Transmitter?

Pressure transmitters (pressure transducers) are classed differently from gauges in that they are more than often specifically designed for remote monitoring vs local indication. In more recent times it has become commonplace to buy a transmitter as well as a pressure gage since prices have come down considerably because of a wide acceptance and the mass production of compact designs. Pressure transmitters are a great plus for industries using PLC’s and dataloggers. In the same way that pressure gages have used mechanical seals to protect internal parts, the pressure transmitters can also be configured with a diaphragm type sensing element for applications that are not considered clean enough.

Common Rule of Thumb for Pressure Transmitter selection:

After the maximum pressure value is known, it is a common practice to choose a pressure transmitter that has a range that is approximately 1.5 times the maximum pressure. It is also possible to use a slightly higher range but it must be understood that the resolution decreases if using a higher range transmitter which does not ever see a pressure that will even reach the middle of it’s range.

What kind of fluid is being measured?

At all costs, it is very important never to allow a situation where a pressure port can be blocked by either a viscous liquid or dirty fluids. In these cases, consider the diaphragm type pressure transmitter which works well on corrosive chemicals, solvents and dirty fluids. If in any doubt, it is advisable to inform the supplier so that the preferred type can be used.

Temperature and Pressure ranges - Accuracy

Always make sure that the pressure transmitter is capable of handling the temperature ranges in the process. Check with the supplier that the model selected it is suitable for your application including the accuracy expected in the given range and application.

Signal Outputs

The most common signal outputs are mA outputs designed for short distanced between controllers and signal monitors. If unsure about the distance, it is best to check the wiring/cabling distances to see whether or not some form of signal amplification is necessary. Other common signal types use voltage and frequency. In the world of instrumentation is quite common to power the devices using a 12 -24 DC voltage.

Easy to install and replace

If this is a prerequisite, then it is advisable to to select pressure transmitters which use common types of connections and connectors. Unpopular connectors can often cause downtime where equipment operators who only needed a generic type of pressure transmitter are faced with having to search for products that are not readily available in the market.

Easy Maintenance /Quality Transducers

Since every manufacturer is going to claim that their pressure transmitter is of exception quality, the best way to ensure a smoother operation is to always have a few spares handy, just in case.

Since there are now so many types of pressure transmitters (evidenced by a wide range to choose from ) it is often best to confer with the manufacturers or their suppliers to suggest the most appropriate type e.g silicon pressure transmitters, capacitance based pressure transmitters, crystal based types etc.