Industrial Process Control, Instrumentation & Control Valve Blog: new york

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Fast and Easy Freeze Protection with Pre-Assembled Self-Regulating Heating Cable

Heat tracing a pipe, from start to finish can be time consuming. Selecting the various components, starting with the heating cable itself, extends through termination kits, controllers, mounting hardware and other electrical hardware needed to put the heating system in operation. BriskHeat has a product that, for many applications, offers a very simple and quick solution.

Pre-assembled self regulating heat cable is available in two voltage ranges, two watt densities, and prefabricated lengths up to 150 feet. Each cable is terminated at each end, saving the installer time. The cable is flexible enough for a spiral installation or to wrap around valves in the piping system. The self regulating aspect of the cable negates the need for a controller and power switching devices. Assemblies targeted for 120 volt applications are provided with a factory installed plug. The 208-277 volt cables will arrive with bare wire leads for installation of a customer provided connector. The cable can be easily installed using fiberglass or aluminum tape. Suitable insulation applied over the finished work will improve the performance of the heating system.

DOWNLOAD THE BRISKHEAT SPEEDTRACE CUT SHEET FROM THE M.S. JACOBS WEB SITE HERE

For more information about freeze protecting pipes, valves, tanks, or vessels contact M.S. Jacobs. Call them at 800-348-0089 or visit their web site at https://msjacobs.com.

Custom Sanitary Coriolis Flow Meter Makes Better Mayonnaise

A large scale producer of condiments for the restaurant industry needed a better way to control the mixture of several ingredients in the production of mayonnaise. The ingredients needed to be mixed at exact ratios to produce a consistent product. The customer wanted to automated the process to remove human error from the mixing of these blends. Products to be measured are starch, an egg blend, and the final product of mayonnaise.

All the ingredient measurements must be made by sanitary instruments because this is an FDA regulated food application. Measurements must also be maintained at relatively low system pressures. This is difficult due to the viscous nature of the product. Because both starch and mayonnaise are shear thinning materials, precise viscosity data is not available, therefore engineering observation of the process was necessary to identify the proper size Coriolis meters.

DOWNLOAD THE FULL APPLICATION SPOTLIGHT

FROM THIS M.S. JACOBS WEB PAGE

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

Self-Regulating Heat Trace for Freeze Protection

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.

Application of Self Regulating Heat Trace in Wastewater Treatment Plant from MSJacobs-Cali

Control Valve Selection - 8 Things to Remember

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:

Control valves are not intended to be a an isolation valve and should not be used for isolating a process.
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.
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.
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.
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.
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.
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.
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.