Showing posts with label instrumentation. Show all posts
Showing posts with label instrumentation. Show all posts

Sunday, September 30, 2018

Mountain States Engineering & Controls

Since 1978, Mountain States Engineering & Controls has served the industrial markets of Colorado, New Mexico, Wyoming, Montana, Utah, Nevada, Idaho, and the western Dakotas.  MSEC is a Manufacturer's Representative & Distributor of process equipment and controls headquartered in Lakewood, Colorado.

We support customers with application, design, and product start-up assistance as well as after-the-sale service and training. It is our absolute goal to ensure that our products and services exceed your expectations.

Mountain States Engineering & Controls represents some of the most recognized and innovative manufacturers in the market today, and carries high quality products designed to meet our customer's most demanding applications. MSEC products solve challenging problems for industrial and commercial applications in the power, chemical, mining, energy, water treatment, and manufacturing industries as well as in universities, hospitals, and government  facilities.

Mountain States Engineering & Controls has on-staff experts ready to assist you in selecting the right product for your application. As we have been for over 40 years, we're there when you need us.

Tuesday, March 31, 2015

Pressure Switches for Industrial Applications

pressure switch
(CCS Dualsnap)

A pressure switch is a device that detects the presence of fluid pressure. Pressure switches use a variety of sensing elements such as diaphragms, bellows, bourdon tubes, or pistons. The movement of these sensors, caused by pressure fluctuation, is transferred to a set of electrical contacts to open or close a circuit.
Pressure Switch Symbols

Normal status of a switch is the resting state with stimulation. A pressure switch will be in its “normal” status when it senses low or minimum pressure. For a pressure switch, “normal” status is any fluid pressure below the trip threshold of the switch.

One of the earliest and most common designs of pressure switch was the bourdon tube pressure sensor with mercury switch. When pressure is applied, the bourdon tube flex's enough to tilt the glass bulb of the mercury switch so that the mercury flows over the electrical contacts, thus completing the circuit. the glass bulb tilts far enough to cause the mercury to fall against a pair of electrodes, thus completing an electrical circuit. Many of these pressure switches were sold on steam boilers. While they became a de facto standard, they were sensitive to vibration and breakage of the mercury bulb.

Pressure switches using micro type electrical switches and force-balanced pressure sensors is another common design.  The force provided by the pressure-sensing element against a mechanical spring is balanced until one overcomes the other. The tension on the spring may be adjusted to set the tripping point, thus providing an adjustable setpoint.

One of the criteria of any pressure switch is the deadband or (reset pressure differential). This setting determines the amount of pressure change required to re-set the switch to its normal state after it has tripped.  The “differential” pressure of a pressure switch should not to be confused with differential pressure switch, which actually measures the difference in pressure between two separate pressure ports.

When selecting pressure switches you must consider the electrical requirements (volts, amps, AC or DC), the area classification (hazardous, non-hazardous, general purpose, water-tight), pressure sensing range, body materials that will be exposed to ambient contaminants, and wetted materials (parts that are exposed to the process media).

Thursday, July 31, 2014

Basics of Flow Meters

flow meter
Flow Meter

Measuring the flow rate of solids, liquids, and gases is referred to as flow measurement, and is a very important and widely used control variable. Many industries such as power, chemical, water, waste-water treatment, energy, mining and petroleum have many requirements for flow measurement and control.

A flow meter is a device that measures the rate of flow or quantity of a moving fluid in an open or closed conduit. There are two basic ways of measuring flow: volumetric basis and weight basis.

Flow measuring devices are generally classified into four groups:
  1. Mechanical type flow meters: Fixed restriction, variable head type flow meters using different sensors such as orifice plates, venturi tubes, flow nozzles, pitot tubes, quantity meters such as positive displacement meters, mass flow meters, etc. 
  2. Inferential type flow meters: Variable area flow meters (Rotameters), turbine flow meters, target flow meters, etc.
  3. Electrical type flow meters:  Electromagnetic flow meters, Ultrasonic flow meters, laser doppler anemometers etc.
  4. Other flow meters: Purge flow regulators, flow meters for solids flow measurement, cross-correlation flow meter, vortex shedding flow meters, flow switches, etc.
Flowmeters need to be integrated into existing piping or new installation. There are two methods for flowmeter installation: inline and insertion. With the inline method, connectors are provided for upstream and downstream pipes. For the insertion method, a sensor probe is inserted into the pipe.

Most flowmeters are installed with straight sections of pipe on either side for flow to normalize. For the inline method, the diameter of pipes should be same as the flowmeter size. Insertion design is easier to install and more economical in large diameter pipes.

To select the suitable flowmeters many factors should be taken in mind. The most important is fluid phase (solid, liquid, gas, steam) and the other is flow condition (clean, dirty, viscous, open channel etc.). The next important factor is line size and flow rate. Other properties that will affect the selection of flowmeter are density, pressure, temperature, viscosity etc. You should consult an application engineer before specifying a flow meter to assure proper installation, lowest installed cost and safety.