Insulation Blankets From Unitherm International

Insulating covers for pipe, fittings, valves
Courtesy Unitherm International

Whether for freeze protection, energy conservation, or personnel safety, insulating blankets and jackets can provide adequate levels of insulating performance in a removable form.

Unitherm International fabricates an extensive array of standard shapes to accommodate almost every conceivable fitting, valve, strainer, or other device found in a piping system. Custom fabrications are available, as well. The insulation jackets are universal and modular in their application, simple to install, rugged and long lasting, delivering energy conservation values far in excess of their cost. Removal and reinstallation of the insulation assembly is easily accomplished when access to the protected fitting or device is required.

A similar assembly is also available as a heated jacket or blanket that delivers even and controlled heat to maintain minimum temperatures in the covered or enclosed item. There are almost uncountable applications for the standard and custom shapes available.

There is more to learn about how insulating jackets and blankets can be applied to improve energy performance and protect assets and personnel. Share your challenges with a product application expert, combining your process and facilities knowledge with their application expertise to develop effective solutions.

Application of Pyrometers in Industrial Settings

Multi-wavelength Infrared Pyrometer
Courtesy Williamson

Pyrometers provide a means of measuring the surface temperature of an object from a distance and without having to physically contact the object. Clearly these are useful tools for many operations and industries. The ability to measure temperature without contact provides isolation of the sensor from the target, as well as the ability to take temperature readings from a distance. A pyrometer does not rely upon intimate contact between sensor and measurement point. This is helpful is scenarios where the shape, location, or content of an object does not accommodate the installation of a temperature sensor. Service technicians can make great use of portable pyrometers when diagnosing machinery or process operation issues.

Pyrometers rely upon the gathering of radiation emitted from the measured surface. The instrument collects the radiation through its optical system and focuses it onto a collector or measuring element. Further internal processing produces the temperature reading in engineering units. There are several variants of IR (infrared) technology applied to pyrometers, but all operate on the same general principle.

Obtaining reliable measurements with pyrometers can require some knowledge and awareness of the emissive properties of the material being measured. There are some applications that are better served through the use of a particular IR measurement technology.

Multi-wavelength pyrometers employ measurement across a number of wavelengths to offset the effects of what are referred to as "non-greybody materials" that adversely impact readings derived through the use of other IR technologies. Algorithms are developed for specific applications that will provide accurate emissivity and temperature readings. Some examples of non-greybody materials.

• Aluminum
• Magnesium
• Stainless Steel
• Brass
• Bronze
• Copper
• Zinc

You can see from the list that many industrial and commercial applications will benefit from the use of multi-wavelength IR measurement. More detail about pyrometers for industrial use are in the document included below. Share your temperature measurement challenges with an application expert and combine your facility and process knowledge with their product application expertise to develop an effective solution.

Infrared Pyrometers for Industrial Use from Hile Controls of Alabama, Inc.

Accurate Thermal Metering For Building HVAC Energy Management

Ultrasonic In-line Thermal Energy Meter
Courtesy Micronics

The modern business climate has, for some now, been spooling up demand for accountability and, even more so, efficiency. Whether you think of efficiency as "doing more with less" or just avoiding the waste of financial, human, or natural resources the end result is the same and calls for similar prerequisites.

We live in a society of buildings, each with a mapped out function. Most buildings are predominantly occupied by people, bringing a requirement to maintain temperature, relative humidity, and air quality at levels of suitable comfort for human occupants. The energy consumption involved with providing that level of comfort stands as a bold line item in the operating expense ledger for any building. That is where accountability and efficiency come in. It is in the building stakeholders' interest to have knowledge regarding rates and quantity of thermal energy usage, as well as efficiency measures of delivered output per unit of input energy.

HVAC (Heating, Ventilation, Air Conditioning) primarily is an endeavor that generates and moves thermal energy throughout an enclosed space. Commercially available technology now allows a building operator to accurately measure that movement of thermal energy throughout a system or building. The process is generally called BTU metering and has a number of justifiable benefits.

• Real time equipment performance measurement.
• Sub metering can indicate specific areas of consumption.
• Ability to directly bill multiple tenants in a single building for their thermal energy usage.
• Monitor and balance energy flows.

BTU metering essentially involves inlet and outlet temperature measurement of heat transfer liquids, along with their flow rate. While the principle is simple, the intricacies of the measurement methods and equipment accuracy can have a substantial impact on the accuracy, and thus the benefit, of the measurement data. Additionally, adding more instrumentation to an already complex system can create an additional on-going maintenance and calibration burden to retain the necessary levels of accuracy and function. Success at gaining the benefit of the performance data while minimizing the additional maintenance burden due to the instrumentation should be the goal.

One solution calls for the use of clamp on or in-line ultrasonic flow meters to measure liquid flow, coupled with temperature measurement in a single unit that will perform necessary calculations and provide output data in useful engineering units. An overarching benefit of the clamp on meter is its non-invasive nature, allowing its retrofit to in-place systems with no disturbance to existing piping. Here are some other characteristics of a highly effective BTU measurement unit:

• No wear mechanism as part of the flow measurement unit
• Traceable accuracy of flow and temperature measurements
• Simple installation in new or retrofit applications without disruption to system operation
• Reliable and maintenance free operation
• Accurate measurement from near zero flow rate to maximum system flow
• Stable sensing with no zero drift
• Communications protocol to match building energy management system
• Large storage cache for data, in case of communication failure
• Common output signals, 4-20 ma or other, usable with selected ancillary equipment

Selecting the right equipment or instrumentation is the most important step along the path of adding measurement capability to increase efficiency. Without a solid stream of reliable data, useful decisions become difficult. Contact a product application specialist and share your requirements and goals. Combining your process and system knowledge with their product application expertise will produce a good outcome.

Close Control of Temperature in Liquid Processes

Temperature sensor or transmitter assemblies for industrial use
Courtesy Weed Instrument

Temperature control is a common operation in the industrial arena. Its application can range across solids, liquids, and gases. The dynamics of a particular operation will influence the selection of instruments and equipment to meet the project requirements. In addition to general performance requirements, safety should always be a consideration in the design of a temperature control system involving enough energy to damage the system or create a hazardous condition.

Let's narrow the application range to non-flammable flowing fluids that require elevated temperatures. In the interest of clarity, this illustration is presented without any complicating factors that may be encountered in actual practice. Much of what is presented here, however, will apply universally to other scenarios.

What are the considerations for specifying the right equipment?

KNOW YOUR FLOW

First and foremost, you must have complete understanding of certain characteristics of the fluid.

• Specific Heat - The amount of heat input required to increase the temperature of a mass unit of the media by one degree.
• Minimum Inlet Temperature - The lowest media temperature entering the process and requiring heating to a setpoint. Use the worst (coldest) case anticipated.
• Mass Flow Rate - An element in the calculation for total heat requirement. If the flow rate will vary, use the maximum anticipated flow.
• Maximum Required Outlet Temperature - Used with minimum inlet temperature in the calculation of the maximum heat input required.

MATCH SYSTEM COMPONENT PERFORMANCE WITH APPLICATION

Heat Source - If temperature control with little deviation from a setpoint is your goal, electric heat will likely be your heating source of choice. It responds quickly to changes in a control signal and the output can be adjusted in very small increments to achieve a close balance between process heat requirement and actual heat input.

Sensor - Sensor selection is critical to attaining close temperature control. There are many factors to consider, well beyond the scope of this article, but the ability of the sensor to rapidly detect small changes in media temperature is a key element of a successful project. Attention should be given to the sensor containment, or sheath, the mass of the materials surrounding the sensor that are part of the assembly, along with the accuracy of the sensor.

Sensor Location - The location of the temperature sensor will be a key factor in control system performance. The sensing element should be placed where it will be exposed to the genuine process condition, avoiding effects of recently heated fluid that may have not completely mixed with the balance of the media. Locate too close to the heater and there may be anomalies caused by the heater. A sensor installed too distant from the heater may respond too slowly. Remember that the heating assembly, in whatever form it may take, is a source of disturbance to the process. It is important to detect the impact of the disturbance as early and accurately as possible.

Controller - The controller should provide an output that is compatible with the heater power controller and have the capability to provide a continuously varying signal or one that can be very rapidly cycled. There are many other features that can be incorporated into the controller for alarms, display, and other useful functions. These have little bearing on the actual control of the process, but can provide useful information to the operator.

Power Controller - A great advantage of electric heaters is their compatibility with very rapid cycling or other adjustments to their input power. A power controller that varies the total power to the heater in very small increments will allow for fine tuning the heat input to the process.

Performance Monitoring - Depending upon the critical nature of the heating activity to overall process performance, it may be useful to monitor not only the media temperature, but aspects of heater or controller performance that indicate the devices are working. Knowing something is not working sooner, rather than later, is generally beneficial. Controllers usually have some sort of sensor failure notification built in. Heater operation can be monitored my measurement of the circuit current.

SAFETY CONSIDERATIONS

Any industrial heater assembly is capable of producing surface temperatures hot enough to cause trouble. Monitoring process and heater performance and operation, providing backup safety controls, is necessary to reduce the probability of damage or catastrophe.

High Fluid Temperature - An independent sensor can monitor process fluid temperature, with instrumentation providing an alert and limit controllers taking action if unexpected limits are reached.

Heater Temperature - Monitoring the heater sheath temperature can provide warning of a number of failure conditions, such as low fluid flow, no fluid present, or power controller failure. A proper response activity should be automatically executed when unsafe or unanticipated conditions occur.

Media Present - There are a number of ways to directly or indirectly determine whether media is present. The media, whether gaseous or liquid, is necessary to maintain an operational connection between the heater assembly and the sensor.

Flow Present - Whether gaseous or liquid media, flow is necessary to keep most industrial heaters from burning out. Understand the limitations and operating requirements of the heating assembly employed and make sure those conditions are maintained.

Heater Immersion - Heaters intended for immersion in liquid may have watt density ratings that will produce excessive or damaging element temperatures if operated in air. Strategic location of a temperature sensor may be sufficient to detect whether a portion of the heater assembly is operating in air. An automatic protective response should be provided in the control scheme for this condition.

Each of the items mentioned above is due careful consideration for an industrial fluid heating application. Your particular process will present its own set of specific temperature sensing challenges with respect to performance and safety. Share your requirements with temperature measurement and control experts, combining your process knowledge with their expertise to develop safe and effective solutions.