Saturday, April 28, 2018

Flameless Explosion Venting

Explosion test
Explosion test without flameless vent.
(Courtesy of Fike)
In the event of a plant explosion, the flames and dust exiting the process vessel threaten a plants personnel, equipment and property. In a normal venting situation, an explosion is freely discharged, with threatening dusts and flames exiting the process vessel. The dust and flame are then channeled down vent ducts and ultimately outside the building. The ductwork has disadvantages though, and indoor plant installations cannot be protected by explosion vents alone.

Flameless venting is highly suited for indoor applications and, used in in combination with explosion vents, can extinguish the flame from the vented explosion without the use of expensive ducting, limitations to equipment location, or more costly explosion protection.  Flameless explosion venting protects people and equipment from flames and dust by using a flame absorber with a mesh filter to rapidly and efficiently cool and extinguish the flames immediately.
Explosion test
Explosion test with flameless vent.
(Courtesy of Fike)

Flameless venting is a viable alternative to ducting.  Since indoor venting is not permitted, the designer has to select between vent ducting and flameless venting, and sometimes flameless explosion venting is the only alternative.

Advantage of Flameless Venting:
  • Eliminates need for expensive ducts
  • Enhanced venting efficiency over venting with ductwork
  • Virtually maintenance free
Explosion venting system designers must take design standards into consideration in order to ensure that the calculated relief area and selected venting devices are compliant with local codes and laws.

Flameless venting must consider venting efficiency and incorporate it in the overall design. The venting efficiency factors of the venting and flameless venting devices are manufacturer product specific, can be application specific and should be used in accordance with the manufacturers’ recommendations only.

It is also critical to discuss your explosion venting application with an applications expert. Gaining their  knowledge and experience can literally mean the difference between success and disaster.

Tuesday, April 17, 2018

Flow-Tech, Inc. Serving Maryland, Washington D.C. and Virginia

Flow-Tech is a manufacturer’s representative and stocking distributor of process instrumentation and calibration equipment in Maryland, D.C and Virginia specializing in the Industrial Process, Control, and Test / Measurement markets.

https://flowtechonline.com
410-666-3200 MD
804-752-3450 VA

Monday, April 9, 2018

What is a Pressure Transmitter?

Differential pressure transmitter
Differential pressure
transmitter (Yokogawa)
A pressure transmitter is a transducer that converts pressure into an electrical signal it outputs both analog and digital signals corresponding to the pressure. A pressure transmitter measures three phenomena: differential pressure; gauge pressure; and absolute pressure. The most common and useful industrial pressure measuring instrument is a differential pressure transmitter. This instrument senses the difference in pressure between two ports and produces an output signal with reference to a calibrated pressure range.

Industrial Applications of Pressure Transmitters

Pressure transmitters are commonly used to measure the pressure inside of industrial machinery or in industrial processes. They are used in various industries such as oil and gas, refining, chemical, pharmacy, and so on.

Pressure Transmitters in Industry

Pressure Transmitters in Industry
Pressure Transmitters in Industry
Pressure transmitters are widely used in industry to measure flow, level, and pressure. There are unlimited industrial applications. Oil and gas flow metering applications are found onshore, offshore and in subsea. It is also often used for monitoring filters in water and effluent treatment plants, monitoring sprinkler systems, and remote sensing of heating systems for steam or hot water. It can monitor pressure drops across valves and can be used to monitor pump control.

Differential Pressure for Flow Measurement

DP flow measurement is one of the most common applications for differential pressure transmitters by measuring the difference in fluid pressure. While the fluid flows through a pipe, it is possible to calculate the flow rate for differential pressure flow measurement. A primary and the secondary element are used. The primary element is designed to produce a difference in pressure as the flow increases. There are many different types of primary element, the most common being the orifice plate, Venturi flow nozzle, and pitot tube. The secondary element is a differential pressure transmitter. It is designed to measure the differential pressure produced by the primary element as accurately as possible. In particular it is important that the differential pressure measurement is not affected by changes in the fluid line pressure, temperature, or other properties such as ambient temperature. A good DP transmitter will ensure that the differential pressure is measured accurately regardless of other changing parameters and will reliably transmit a signal to represent the differential pressure. The DP flow transmitter output signal may also include square root extraction for flow calculation, although it is common for this function to be handled in a control system. In a typical control loop, the transmitter signal is fed to the controller whose output is used to regulate the flow rate through a control valve.

Differential Pressure for Flow Measurement
Differential Pressure for Flow Measurement


Differential Pressure for Level Measurement

Differential pressure transmitters can also be used for tank levels by measuring the pressure. The transmitter is installed at the bottom of the tank whose level is to be detected. In case of a sealed tank, a transmitter with capillaries measures a differential pressure between the upper side and the bottom side. The liquid inside the tank at the bottom creates pressure which is higher than the pressure at the top. The difference in these pressures can be used to calculate the level. In case of an open tank, the transmitter measures the differential pressure between the liquid inside the tank and the reference atmospheric pressure. In a typical control loop, the transmitter signal is fed to the controller whose output is used to regulate the tight level through a control valve.

Differential Pressure for Level Measurement
Differential Pressure for Level Measurement