Friday, October 31, 2014

A Tutorial on Replacing the Tube in the Brooks Instrument Sho-Rate 1350G & 1355G Glass Tube Flow Meters

For anyone using the Brooks Instrument "Sho-Rate" 1350G or 1355G glass tube flow meter, here is a handy video on how to replace the tubes.

For more information contact:

Belilove Company Engineers 
21060 Corsair Blvd
Hayward, CA 94545
Phone: 510) 274-1990
Fax: (510) 274-1999

Saturday, October 18, 2014

2-Wire and 4-Wire Transmitters and Control Loops

field transmitter
Digital Meters
Industrial process control transmitters commonly provide analog signals, such as 4-20 milliamps (mA), 1-5 volts DC, and 10-50 milliamps as outputs which can be scaled to the control range of the process variable they are sensing. Industrial transmitters are either “4-wire” or “2-wire” which defines how the transmitter gets its supply or “excitation” voltage.

4-wire transmitters have four wires exiting the device. Two wires are for the supply power of the device, typically 120 volts AC, 240 volts AC or and external 24 volts DC supply. The other two wires provide the analog output signal provided by the transmitter circuitry.

loop power
2-wire, loop power example
2-wire transmitters have only two wires exiting the device and rely upon the control “loop” for the excitation voltage - typically 24 volts DC which normally comes from the loop controller, PLC or DCS.

4-wire devices are also classified as “active” (supplying power) devices, while 2-wire devices are classified as “passive” (loop powered) devices.

For example, a digital meter (active) may provide loop power to a pressure transmitter. The pressure transmitter regulates the current on the loop to send the signal back to the digital meter, but since the transmitter does not provide power to the control loop, it is deemed passive. In another example, a passive (loop powered) digital meter and a passive pressure transmitter may be used in the same loop, but uses a 24 V battery as the active device to power the loop.

Monday, October 13, 2014

Industrial Electric Immersion Heaters

electric immersion heaters
Screw plug and flanged
immersion heaters
(courtesy of Durex)
Electric immersion heaters are used in a myriad of industrial applications. From drying industrial gasses, to freeze protecting cooling tower sumps, to heating acids in plating applications, the versatility of electric heating element can save time, energy and space.

Industrial immersion heaters are used to directly heat a standing or moving fluid by using electric heating elements. There are three primary types of industrial electric immersion heaters; screw-plug heaters, flanged immersion heater, and over-the-side heaters.

At the heart of industrial immersion heaters are the individual heating elements, normally constructed from a stainless steel or Inconel tube containing a magnesium oxide filler and a nichrome resistance wire. Current is applied to the wire which produces the heat, while the compacted magnesium oxide powder provides the electrical insulation, and the metallic tube provides the physical protection.

Thursday, October 9, 2014

Mounting a Rack and Pinion Pneumatic Actuator to a Ball Valve

This video, courtesy of AT Controls,  introduces the viewer to the steps in mounting a pneumatic rack and pinion actuator to an industrial ball valve. Steps include matching valve and actuator, checking fit, connecting mounting hardware (brackets and couplings), assuring position, assembly and test.

Sunday, October 5, 2014

Analytical Measurement for Fluids and Processes

The need to perform chemical analysis on samples or sample streams exist in virtually all process systems, large and small. Whether a solid, liquid, or gas, the use of an analyzer to automatically provide detailed process information is required for product quality, manufacturing efficiency and safety. In many situations, sampling be done automatically.

In situ analyzer
In Situ Analyzer
Analyzers connected to a process and providing automatic sampling are called in situ analyzers. For these, the sensor is placed in the process vessel or stream of a flowing material to be analyzed.

A second online method, fluid sampling, passes a sample of the process directly into an analyzer where the handling pressure and temperate can be controlled. This is normally done for for fluids (liquids or gases). The sample stream can then be returned to the process or discarded. It is common for these type of analyzers to incorporate pressure reducing valves, small pumps and perhaps internal electric heating elements that prepare the samples for testing.

Thursday, October 2, 2014

Industrial Ball Valves

industrial ball valve
Internal view of an industrial ball
valve (courtesy of Cameron TBV)
Ball valves are defined by their body style, the five major styles being: Uni-body; 3-piece; split-body; top-entry; and welded body. They are further defined by the machined hole in their ball (also known as the port); the categories being "standard port" or "full port".

On a full port valve, the port is the same size as the pipeline, resulting in a better flow profile and no restriction or pressure drop. A full ported ball valve, with better flow coefficients, comes at a higher price. In many application they are necessary because a reduction in diameter, or the resulting change in flow, can be detrimental.

The reduction in a standard port valve is one pipe size smaller than the pipe connected to the valve, resulting in restricted flow and increased velocity through the valve.