Thursday, October 25, 2018

Leading the Way in Instrumentation and Control Since 1945


M.S. Jacobs and Associates is a leading manufacturer's representative and distributor of industrial instrumentation and controls serving Western Pennsylvania, West Virginia, and New York State. Since 1945, the company's dedication to the industrial market has resulted in a broad offering of superior quality products for flow, level, pressure, and temperature measurement, as well as filtration products. M.S. Jacobs is known for solving tough applications and providing exceptional customer service with a team of highly trained outside and inside personnel.

MS Jacobs' products have contributed to the success of all major industrial markets, including power generation, chemical processing, pulp and paper, oil and gas production, water and wastewater treatment, and nuclear power generation. For over 70 years, M.S. Jacobs has continuously been there, providing support and service to their customers.

800-348-0089

Monday, October 15, 2018

Industrial Pressure and Temperature Switch Operating Basics

pressure switch
Internal view of pressure switch.
(Ashcroft)
A pressure switch is a mechanical device that detects the presence of fluid (gas or liquid) pressure. Pressure switches use a variety of sensing elements to convert pressure changes to linear movement. These sensors are known as diaphragms, bellows, bourdon tubes, and pistons. The movement of these sensors, caused by pressure fluctuation, is transferred linearly through a rod or piston to a set of electrical contacts to open or close a circuit.

The opening and closing of the electrical circuit is done through electrical contacts. These electrical contacts are most often enclosed in their own housing in an assembly known as a microswitch. These contacts in the pressure switch are associated with the terms "normal", as in "normally open" or "normally closed". The 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.

Switch Symbols
Switch Status Symbols
Some of the earliest and most common designs of pressure switch was combining the bourdon tube pressure sensor with mercury switch. A bourdon tube is basically a curved tube that flexes straight when pressure is applied. The bourdon tube's flex is amplified through gearing and made significant enough to tilt the glass bulb of the mercury switch so that the mercury flows over the electrical contacts, thus completing the 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 and resulting mercury contamination.

Explosion proof pressure switch
Explosion proof pressure switch.
(Ashcroft)
Another common design feature pressure switches use is referred to as force-balanced pressure sensors.  This design operates by countering the force provided by the pressure-sensing element with a mechanical spring. The system remains static until the pressure-vs-spring balance is overcome. Once the sensor pressure exceeds the spring tension, movement occurs and the electrical switch state is changed. In this design, the tension on the spring may be adjusted to set the tripping point, thus providing an adjustable setpoint.

Deadband or (reset pressure differential) is one of the most important application considerations when applying a pressure switch. This setting determines the amount of pressure change required to reset 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.

Temperature switch
Temperature switch
(Ashcroft)
Temperature switches operate on exactly the same principle, but use the concept of thermal expansion, instead of direct pressure sensing, to create the the movement required to change the electrical contact status. In the enclosed thermal sensor (referred to as the bulb, or bulb and capillary), the liquid enclosed in the system expands and contracts in relation to temperature change. That expansion and contraction is then converted to linear movement,  and then used to open and close an electrical circuit.

There are many, very important details that need to be considered when selecting and applying pressure and temperature 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, temperature range, and material compatibility. It's highly recommended you consult with a process instrumentation expert for assistance.

Saturday, September 29, 2018

Cashco Control Valves: Product Summary

Cashco Control Valve
Cashco Ranger QCT
Cashco, headquartered in Ellsworth, Kansas, manufactures a proprietary line of throttling rotary and linear process control valves and sanitary control valves.

Current models and designs are:
  • Models 988 and 989 - Globe-style control valves with pneumatic spring-return actuator.
  • Model 988-MB - a modified version of our Model 988 designed to handle hazardous fluids.
  • Ranger QCT - universal control valve  that offers 10 different trim combinations which can easily be changed without disturbing the packing, actuator, or positioner calibration.
  • Model 521 - Globe-style control valve with sliding stem, bellows sealed, pneumatically actuated valves designed to achieve the ultimate in long-term corrosive chemical service.
  • Premier EZO (short for easy opening) - Superb throttling characteristics and is designed to eliminate “popoff” flow surges. 
  • Model 987 - Precision globe-style “chemical valve” is the valve to handle hostile fluids and environments – as well as steam and water. 
  • Model 2296/2296HF - A stainless steel or bronze glove-style control valve available with pneumatic or electric actuators. 
  • Model 964 - A globe-style pneumatic control valve for general plant utility services.

800-348-0089

Tuesday, September 11, 2018

Magnetrol Pulsar Model R86 26 GHz Pulse Burst Radar Level Transmitter

The Magnetrol PULSAR Model R86 radar transmitter is based on pulse burst radar technology combined with equivalent time sampling circuitry. Short bursts of 26 GHz microwave energy are emitted and subsequently reflect- ed from the liquid level surface. Distance is first measured by the equation:

D = Transit time (round-trip)/2

Applications:
  • Media: Liquids and slurries; hydrocarbons to water- based media (dielectric 1.7–100, 1.4 in stillwell)
  • Vessels: Most process or storage vessels up to rated temperature and pressure. Pits and sumps as well as glass-lined tanks.
  • Conditions: Virtually all level measurement and control applications including process conditions exhibiting varying specific gravity and dielectric, visible vapors, high fill/empty rates, turbulence, low to moderate foam and buildup.


https://msjacobs.com
800-348-0089

Friday, August 31, 2018

Level Sensors for Corrosive Liquids

Levelpro plastic level sensors
ICON Levelpro plastic level sensors.
Corrosive liquids can be found in just about every industry; food, metal finishing, water-waste water treatment, textile, automotive, to name just a few.  When it comes to selecting the correct sensor technology there are many different factors to consider.

Plastic level sensors are an excellent choice for corrosive liquid chemical applications.  Plastics, unlike metals, do not corrode; however, they can deteriorate and swell if the correct plastic is not used.

ICON Process Controls offers its Levelpro plastic level sensors for continuous level indication, as well as plastic level switches for point level notification.  There are many different factors to consider when selecting the right product for the application.

  • Chemical Liquid?
  • Concentration?
  • Temperature?

With this information a material of construction for the level sensor can be selected.  Next, it is important to understand other factors that contribute to the success or failure of the level sensor.

  • Is there particulate with the liquid?
  • Does the liquid create a film, or does it have a coating effect?
  • Does the chemical produce foam?
  • Is there sludge at the bottom of the tank?
  • Is the liquid agitated?

Once the information pertaining to the chemical and the type of sensor technology (continuous or point) is determined, ICON can recommend the most suitable product for the application.

An excellent level sensor for corrosive liquids is the 100 Series submersible level sensor.  The plastic level transmitter is available in PVC, PP and PVDF bodies, and comes standard with a corrosion-resistant PTFE jacketed cable and Kalrez O-rings.  The 100 Series submersible level sensors incorporate a weighted body which ensures the sensor sits at the bottom of the tank.  The plastic level transmitter has a ceramic sensing diaphragm that measures the head pressure of the liquid.  These level sensors are not affected by foam, vapor, condensate or turbulence, making them an excellent choice for many different applications.

If the chemical produces sludge then ICON would recommend a non-contact level technology such as the Ultrapro ultrasonic level sensor, or the Proscan radar transmitter.

For clean liquids the CFL Series continuous float is a reliable and economical choice.

ICON also offers a complete line of plastic level switches for point level indication.  These plastic switches are available in PVC, PP and PVDF materials, and the relay can be set to normally open or normally closed positions. Visit M.S. Jacobs at https://msjacobs.com for more information.

WIKA Phases Out PSD-30 and PSD-31 Pressure Switches, Replaced with PSD-4 Pressure Switch

PSD-4 Pressure Switch
The WIKA PSD-30 and PSD-31 pressure switches are currently being phased out, to be replaced with the newly updated PSD-4 pressure switch.

The model PSD-4 pressure switch represents the extensive development of the  PSD-30 pressure switch.  A high accuracy of 0.5 %, freely configurable output signals (PNP/NPN, 4-20 mA / 0-10 V), the 5:1 scalability of the analog output, in addition to outstanding self-diagnostics, make the PSD-4 an excellent automation solution for industrial machines, hydraulic systems, and pneumatic systems applications.

While the PSD-4 offers new features and functionality, pricing is comparable to that of the PSD-30 and PSD-31.  This new pressure transmitter offers customizable features, such as allowing the user to select the switch type and output signal, while offering a 5:1 turndown ratio.  Additionally, this transmitter is an economical solution for applications requiring local display with an analog output signal.  The PSD-4 provides an upgrade in quality and customizability without negatively affecting budgets.

During development of the WIKA switch family a high value was placed on a robust design and the selection of appropriate materials suited to machine-building applications.  For this reason the case and the threaded connection of the electrical connector are made from stainless steel.

For more information, contact M.S. Jacobs by visiting https://msjacobs.com or by calling 800-348-0089.

Friday, July 20, 2018

M.S. Jacobs: Dedicated to Service and Excellence in Process Control

M.S. Jacobs and Associates has been a leading manufacturer's representative and distributor of industrial instrumentation and controls since 1945.  Expanding from its original focus on the steel industry, MS Jacobs services and supplies products in all major industrial markets, including power generation, chemical processing, pulp and paper, oil and gas production, water and wastewater treatment, nuclear power, pharmaceutical, institutional, and alternative energy.