Showing posts with label pennsylvania. Show all posts
Showing posts with label pennsylvania. Show all posts

Thursday, February 2, 2017

Self-Regulating Heat Trace for Freeze Protection

self-regulating heat cable heat trace
Example of self-regulating heating cable
Courtesy BriskHeat
Freeze protection is probably the most obvious application range for heat trace tape and cable. The applications are vast in number throughout the geographic region where real winter comes every year. Pipes, valves, tanks, vessels, conveyors and other equipment are all vulnerable to excessively cold conditions. Properly configured heating cable, blankets, or other shapes can reduce the risk of freezing liquids and keep protected items at safe operating temperatures.

Though freeze protection heating equipment and materials are available in many shapes, forms, and materials, this article will focus on self-regulating heating cable.

There are two basic types of heating cable. 


Constant wattage cable provides continuous full output whenever energized. It's application requires some means of limiting the temperature of the heated object. This can be a thermostat, or some other temperature controller and sensor combination. This simple on/off control is effective in many cases. More sophisticated arrangements can be accomplished with heater power controllers and a closed loop control system. The objective is to apply only as much heat (and energy) as necessary to prevent freezing or other cold induced undesirable conditions.

Self-regulating cable is designed and fabricated in a manner that reduces the heat output of the cable as its temperature increases, providing a built-in means of limiting applied heat without the need for any other means of control. Properly selected and installed heat cable of the self-regulating type will apply only the heat energy needed to maintain the desired condition. No other devices are required.

There are many heating solutions available for freeze protection to suit any application. Share your process heating and freeze protection challenges with product application specialists, combining your process knowledge and experience with their product application expertise to develop effective solutions.



Wednesday, January 25, 2017

Hinge Restrained Expansion Joints for Process Piping

cutaway hinge restrained expansion joint for piping
Cutaway view of hinge restrained expansion joint
Process piping of sufficient size or extent can require allowances be made for expansion of the piping material in the installed location. The design criteria will include factors that impact the expansion of the piping components, as well as the relationships between the piping and elements of their supporting structures. Expansion can produce substantial movement of pipe sections which must be accommodated by the supports and the piping itself.

One manufacturer, General Rubber Corp., provides a hinge restrained rubber expansion joint that is designed to allow angular rotation of a piping section within a single plane. The expansion joint isolates the movement of one pipe section from its adjacent connected section. The assembly is comprised of a pair of pin connected hinge plates attached to the expansion joint hardware. The company further describes the unit construction and function...

The hinge assembly must be designed for the internal pressure thrust forces of the system. They can be used in sets of two or three to absorb large lateral movements in a single plane. This optimally designed arrangement is an effective solution for absorbing large axial thermal movements from an adjacent pipe run. Its spool type body is constructed with full rubber flanges, a high-grade leak proof-tube, multiple layers of high-strength tire cord, high tensile steel reinforcement and a seamless cover. They are commonly used when the support structure or adjacent equipment have load limitations. The economic benefits of this arrangement include a smaller system footprint with far fewer anchors and guides.
The video included below provides an animated illustration of how the expansion joint functions. More information is available from product specialists, with whom you should share your process piping system challenges.

Wednesday, January 18, 2017

Hazardous Gas and Flame Detection

CO2 gas detector for industrial safety
Carbon dioxide level detector
Courtesy Sierra Monitor Corp.
MS Jacobs handles the Sierra Monitor line of gas and flame detection devices for use in commercial and industrial facilities. SMC manufactures complete solutions for gas and flame detection, from the sensors to the monitoring and control stations. The systems approach includes sensor modules, controllers, and software working together to provide detection, alarm, analytics, and delivery of all necessary information across communications networks.

SMC employs a variety of technologies to provide application matched performance in their gas and flame detectors. The company innovates and leverages their IIoT (Industrial Internet of Things) expertise to bring operating efficiency and enhanced levels of protection to customer facilities. Systems are tailored to provide the level of protection appropriate for a facility or application, as well as a customized response.

The various sensor  modules are optimized for their intended application range, bringing accuracy and efficiency to hazardous gas and flame detection. Some of the benefits include:

  • Low power requirements
  • Rapid response
  • Various filtering means to discriminate between noise and real hazards
  • Multiple output options that include relays, analog, and digital communications
  • Long calibration intervals for reduced maintenance
  • Remote sensor configuration
  • Self diagnostics
  • Local display
  • More
Share your gas and flame monitoring challenges with application specialists, combining your process and facility knowledge with their product application expertise to develop a comprehensive and effective solution.

Monday, January 9, 2017

Niagara Meters: Overview of Flow Measurement Devices

external view cutaway view target flowmeter
Cutaway and exterior views of target flowmeter
Niagara Meters, based in Spartanburg, South Carolina, is a well recognized brand in the flow measurement field. For over a hundred and fifty years, their products have been used in a myriad of industries, including agriculture, petrochemical processing, and even aboard United States Navy ships. The company’s flow meter products target three basic functions: flow measurement of liquid, gas flowmeters, and flowmeters for steam. The three product application groups are anchored by Niagara’s operating technology thesis statement, “specializing in innovative, reliable products.”

The largest array of Niagara meters are those utilized for liquid flow measurement. For measuring liquid in an open channel, such as a weir or flume, Niagara offers an application specific ultrasonic open channel flowmeter, which comes equipped with one or more sensors, along with a level monitor. The device is flexibly configurable for different arrays, and calculates liquid level, open channel flow and differential level measurement.

cutaway view turbine flowmeter
Cutaway view of turbine flowmeter
Measuring potable water flow through a pipe branch or system can be accomplished easily with the reliable mechanical MTX/WPX model series. In this turbine technology flowmeter, water pressure and resulting flow drives the internal turbine rotor. Magnetic coupling of the rotor to a flow indicator makes this instrument simple, reliable, and rugged for totalizing, rate of flow, and batch control applications.

Flow measurement in applications involving liquids with viscosity similar to oil are candidates for Niagara’s positive displacement oscillating piston flowmeter. This positive displacement device employs a piston which rotates in a flow chamber inside the meter. Liquid flow forces the piston to rotate, with the rotations recorded by a totalizer or pulse transmitter. Mechanical and smart electronic versions are available in a number of variants to meet the range of register and interface requirements.

Another mechanical positive displacement technology from the company uses a nutating disc and gear train to measure flow and provide a totalized flow register. The nutating disc is precisely fitted into the flow chamber and wobbles in a predictable manner that can be counted and used to measure volumetric flow. As with the oscillating piston products, a wide array of variants, including a smart meter version, are available to accommodate any register requirement.

Niagara also offers a fully electronic magnetic flowmeter, or Magmeter. The 6600 Series Magmeter can only be applied with conductive fluids, and converts the voltage produced when the fluid flows through a magnetic field to a volumetric flow signal for a high accuracy solution with no moving parts.

The company offers one additional category of flowmeter technology; applicable to liquids, gas, or steam. The target meter has a solid disk (the target) located in the flow path. The dynamic force of fluid movement acting on the target is converted to an electrical output signal that is proportional to flow rate.

All of Niagara’s flow measurement devices are time proven through many applications. For assistance in selecting and configuring a flowmeter for a particular application, share your requirements and process measurement challenges with a product specialist. The combination of your process knowledge and their product application expertise will produce effective solutions.

Thursday, October 2, 2014

Control Valve Selection - 8 Things to Remember

control valve
Cashco Control Valve
Choosing an improperly applied sized or improperly sized control valve can have serious consequences on operation, productivity and most important, safety. Here is a quick checklist of basics that need to be considered:

  1. Control valves are not intended to be a an isolation valve and should not be used for isolating a process. 
  2. Always carefully select the correct materials of construction. Take into consideration the parts of the valve that comes in to contact with the process media such as the valve body, the seat and any other "wetted" parts. Consider the operating pressure and operating temperature the control valve will see. Finally, also consider the ambient atmosphere and any corrosives that can occur and effect the exterior of the valve. 
  3. Put your flow sensor upstream of the control valve. Locating the flow sensor downstream of the control valve exposes it to an unstable flow stream which is caused by turbulent flow in the valve cavity.
  4. Factor in the degree of control you need and make sure your valve is mechanically capable. Too much dead-band leads to hunting and poor control. Dead-band is roughly defined as the amount of control signal required to affect a change in valve position. It is caused by worn, or loosely fitted mechanical linkages, or as a function of the controller setting. It can also be effected by the tolerances from mechanical sensors, friction inherent in the the valve stems and seats, or from an undersized actuator. 
  5. Consider stiction. The tendency for valves that have had very limited travel, or that haven't moved at all, to "stick" is referred to as stiction. It typically is caused by the valves packing glands, seats or the pressure exerted against the disk. To overcome stiction, additional force needs to be applied by the actuator, which can lead to overshoot and poor control.
  6. Tune your loop controller properly. A poorly tuned controller causes overshoot, undershoot and hunting. Make sure your proportional, integral, and derivative values are set).  This is quite easy today using controllers with advanced, precise auto-tuning features that replaced the old fashioned trial and error loop tuning method.
  7. Don't over-size your control valve. Control valves are frequently sized larger than needed for the flow loop they control. If the control valve is too large, only a small percentage of travel is used (because a small change in valve position has a large effect on flow), which in turn makes the valve hunt. This causes excessive wear. Try to always size a control valve at about 70%-90% of travel.
  8. Think about the type of control valve you are using and its inherent flow characteristic. Different types of valve, and their disks, have very different flow characteristics (or profiles). The flow characteristic can be generally thought of as the change in rate of flow in relationship to a change in valve position. Globe control valves have linear characteristics which are preferred, while butterfly and gate valves have very non-linear flow characteristics, which can cause control problems.  In order to create a linear flow characteristic through a non-linear control valve, manufacturers add specially designed disks or flow orifices which create a desired flow profile.
These are just a few of the more significant criteria to consider when electing a control valve. You should always discuss your application with an experienced application expert before making your final selection.