Month: December 2022

What is the difference between instrumentation and metrology?

Posted on by Scott Hackett

Instrumentation and metrology are two terms that often get confused in some ways as they both relate to measuring. In this article, we’ll be clarifying the difference between instrumentation and metrology as well as defining each one and their role within industrial temperature measurement.

What is instrumentation?

Instrumentation is a fairly broad and general term used to describe the hardware that is used for measurement and control and can include software too. The English word “control” often includes regulation as well whilst other languages typically differentiate between manual control such as opening and closing a valve, and automatic regulation, like closed loop control. Therefore, when we consider “instrumentation” it might include valves, manometers, level indicators, and PLC controls.

What is metrology?

Metrology is the science of measurement and how it’s applied. By contrast to instrumentation, metrology is not just about the physical and routine making of measurements, it is more about the infrastructure in place that ensures we are confident in the accuracy of the measurement. It establishes a basic understanding of units and measurement processes that are essential to human activity.

Metrology details the accuracy, precision, and repeatability of a measurement. It includes traceability or comparison with a “standard” or between different measuring systems. Also, it involves all the theoretical and practical aspects of measurement, no matter the measurement uncertainty or the field of application.

What is the difference between instrumentation and metrology?

To understand the difference between instrumentation and metrology, if you consider that philosophy is ‘thinking about thinking’ then metrology is essentially ‘measuring measurement’. So, a lot of people can use and carry out instrumentation but not as many people do metrology. Both are important aspects of high temperature measurement to ensure it is done effectively, safely, and accurately.

Who are TRM?

Thermal Resources Management (TRM) provide engineered solutions and industrial heating elements that perform effectively at the highest temperatures and in the harshest environments. Our team is committed to providing tailored turn-key solutions in various applications including:

  • Electric trace heating- we can design, manufacture, install/train, and control entire heat tracing systems to make up for heat losses in various areas.
  • Temperature measurement- industrial thermocouples and temperature measurement sensors can measure temperatures of up to 2300C! They are used in a broad range of applications and industries from pipelines to steel foundries and hazardous areas like Nuclear Power Station reactors and boilers.
  • Fire survival wiring- the only authentic fire survival cable on the market, guaranteeing more than 3 hours of escape time in the most severe of fires. We can provide heavy duty and light duty cables in both copper and alloy 825, depending on your requirements.

Our R&D and engineering team are on hand to work with you on bespoke, innovative solutions to your project challenges. We operate in a wide range of commercial and industrial sectors such as oil and gas, petrochemical, pharmaceutical, food and beverage, chemical, and many more. To find out how we can help you with your temperature management, contact our professional team today and get on the path to cost savings and more efficient processes.

What is electrical heat tracing?

Posted on by Scott Hackett

Maintaining or raising the temperature of pipes, instrument impulse lines, and vessels in cold conditions with specialised cables is called electrical trace heating or heat tracing. This type of heat trace is broadly used due to its impressive effects at protecting pipes and other important building elements from freezing. Care should be taken when heating elements are chosen to make sure that they are not possible sources of ignition. There are multiple types of cable available such as mineral insulated and self-limiting. 

Trace heating UK is normally considered in the following conditions: 

  • When there is a risk of pipes freezing. Dead legs or other fluids that are susceptible to freezing are common in cold weather, and trace heating can help prevent this from happening.  
  • Hot water systems typically use trace heating to maintain the temperature of the system. 
  • To keep process temperatures consistent for smooth and efficient running of an industrial plant and equipment. For instance, higher temps make heavy/waxy oils flow better, so trace heating is typically applied to those lines. 

There are a number of considerations involved in the design and installation of electric heat trace cable to make sure the system will work properly during start-up and regular plant operation. The thermostat sensor should be properly located and set at the right temperature. Also, there should be a way of indicating that the cable is working as it should be. 

All pipes, vessels, and impulse lines are at risk of heat loss when their temperatures are greater than the ambient temperature. The rate of heat loss can be reduced by using thermal insulation, but it doesn’t eliminate it completely. Electrical trace heating can help to replace some or all of the heat that is lost from the surface, depending on the desired outcome (prevention of freeze or temperature maintenance).  

A thermostat can be used to turn the heat off when the temperature is below the set point and turn it back on when it is a few degrees above the set point. Alternatively, increasingly common control is supplied from microprocessor-based monitoring and control systems, either stand-alone or within the plant control system. 

There are three main types of heat tracing cables available: 

  • Constant power cables 
  • Constant wattage cables 
  • Self-regulating cables 

Each style of trace heating cable operates differently, and the selection of cable will likely depend on the intended application. 

Constant power cable tracing 

This cable, sometimes known as series resistance, consists of a high-resistance wire insulated and encased in a cover. When used at its voltage, it produces thermal energy from the wire’s resistance. 

A key benefit of constant power trace heating is that is usually inexpensive and can maintain extremely high temperatures (particularly mineral insulated cables) for longer lines. Mineral insulated cables are also useful for sustaining lower temperatures on lines which can get very hot like high temperature steam lines. 

Constant wattage cable tracing 

A constant wattage cable has multiple power zones made by wrapping a heating element around two insulated bus wires. By fusing the element to the conductor wire in notches cut in the insulation, a heating circuit is created along the full length of the cable. There is an internal jacket that separates the bus wires from grounding braid. 

The main advantage of this trace heating method is that the parallel circuitry of the cable allows for precise cutting to the desired length in the field. Another advantage is the ability to attach a constant wattage heating tape using either the jointing kit or the trace heating junction box. 

Self-regulating cable tracing 

Self-regulating cable alters heat output based on the heat loss from the pipework by varying its conductivity. As the pipe’s temperature decreases, the polymer core’s electrical conductivity increases, boosting the cable’s output. However, when the pipe’s temperature increases, its conductivity decreases, resulting in decreased output. 

The cable uses two parallel bus wires which transport electricity but don’t produce significant heat. A semi-conductive polymer containing carbon encases the cables. When heated, it restricts current. The cables are constructed, then exposed to radiation, controlling the carbon content and dosage to make different cables with varied outputs. 

Self-regulating cable offers advantages such as customisable length on-site, improved energy efficiency by reducing output at higher temperatures, and protection from overheating and burning out if mis-wired during installation. This makes them especially advantageous for more hazardous applications. 

Summary 

We hope you have found this guide on electrical heat tracing useful. If you’re looking for experienced trace heating suppliers, then TRM can help. Our team provide full turn key solutions that will work specifically to the requirements of your building and operations. Contact us today to discuss your trace heating needs.

What is time lag in process control?

Posted on by Scott Hackett

Industrial temperature measurement processes can have the characteristics of delaying and holding back changes in the values of the process variables. Time lags in process controls typically describes these process delays and the lags are caused by three properties of the process. These properties are resistance, capacitance, and transportation time. 

Resistance 

Resistance is the part of the process that opposes the movement of energy between capacities. For example, in a lubrication oil cooling system, the walls of the lubrication oil cooler work in opposition with the transfer of heat from the lubrication oil within the tubes to the cooling water outside the tubes. 

Capacitance 

Capacitance is the ability to store energy during a process. Being able to store energy means the process can be held back. 

Transportation time 

This is the time required to carry a change in a process variable from one location to another in the process. The time lag not only delays or blocks a change, but it is also during the time delay that no change is happening at all. 

Control system stability 

The part of a control mode that helps a process variable go back to being a steady value after a disturbance is known as “stability”. In other words, stability is the control loop being able to return a controlled variable back to a steady, non-cyclic value, after a disruption. 

Control loops can be either stable or unstable. Instability is the result of a mixture of process time lags (resistance, capacitance, and transportation time) and natural time lags within a control system. This causes slow response to changes in the controlled variable. Therefore, the controlled variable will constantly cycle around the set point value. 

Who is TRM? 

Thermal Resources Management (TRM) provide engineered solutions and industrial heating elements that perform effectively at the highest temperatures and in the harshest environments. Our team is committed to providing tailored turn-key solutions in various applications including: 

  • Electric trace heating- we can design, manufacture, install/train, and control entire heat tracing systems to make up for heat losses in various areas. 
  • Temperature measurement- industrial thermocouples and RTDs can measure temperatures of up to 2300C! They are used in a broad range of applications and industries from pipelines to steel foundries and hazardous areas like Nuclear Power Station reactors and boilers. 
  • Fire survival wiring- the only authentic fire survival cable on the market, guaranteeing more than 3 hours of escape time in the most severe of fires. We can provide heavy duty and light duty cables in both copper and alloy 825, depending on your requirements. 

Our R&D and engineering team are on hand to work with you on bespoke, innovative solutions to your project challenges. We work in a wide range of commercial and industrial sectors such as oil and gas, petrochemical, pharmaceutical, food and beverage, chemical, and many more. To find out how we can help you with your temperature management, contact our professional team today and get on the path to cost savings and more efficient processes.

What is Rock Wool Insulation?

Posted on by Scott Hackett

Rock wool insulation comes from a volcanic rock that is melted at a temperature of roughly 1,600C and then spun into wool. The newly created insulation is then bound together using resins and oils, giving the material waterproof qualities too. In this guide, we’ll be looking how rock wool insulation is used in relation to trace heating UK and the advantages of it. 

How is rock wool insulation used? 

Pretty much all the insulation within a building can be done with rock wool, the walls, roof, and floor. Not only does rock wool insulation provide thermal insulation, but it also has many benefits relating to noise and fire too. Therefore, it can work with trace heating cable to help with fire protection and sound insulation as well. This suggests that it doesn’t have an organic breeding ground, meaning rock wool is entirely immune to mould and rot. 

What are the advantages of rock wool? 

Every insulation material has its own set of characteristics and work methods. This means that no one job is the same and you might need to select different insulation materials depending on the project. Below you can see some of the main advantages of rock wool insulation. 

Vapour permeable material 

In comparison to chemical products such as polyurethane foam, rock wool insulation is a vapour permeable material. So, damp can freely move around and evaporate, and the likelihood of damp problems stays minimised. With this is mind it is clear to see why rock wool is so frequently used for cavity wall insulation, as the cavity often touches damp. 

Insulation value doesn’t change 

A lot of insulation materials lose some of their insulation value as time goes by, but this doesn’t apply to rock wool. The initial value of rock wool will not change, so you will always be suitably insulated. 

Rock wool vs glass wool 

Unlike glass wool, rock wool insulation does not cause skin irritation to the same degree, making it easier to have installed. 

Are there any disadvantages to rock wool insulation? 

Some people prefer to go with fibreglass insulation over rock wool and the main reason behind this is the cost. The purchase price of rock wool is normally about 10% higher than fibreglass and other types of insulation. To make the right price comparison, it is best to consider the density of the insulation (quantity of material per cubic metre). Although this can vary widely from producer to producer, which naturally impacts the price and insulation value. 

What is the weight of rock wool insulation? 

The weight of rock wool comes down to the application it is being used for, the categories are: 

  • Around 23kg/m3 in the case of blankets 
  • 30 to 80kg/m3 boards for common application, insulation, or cavities between beams 
  • Approximately 90 to 150kg/m3 for applications under load, roof boards, and floating floors 

Types of rock wool insulation 

Foil faced insulation batts 

Foil faced insulation blankets are used for insulating roofs and stories. They are much cheaper than other types of insulation, but it can be difficult to get the batts into place. These insulation blankets can come in different finishes that will facilitate application onto the beams. 

Standard insulation boards 

Standard rock wool boards are mainly used to insulate cavity walls. They are very easy to install, and the boards can hide irregularities in the masonry. As a result of this, you can be sure that the external wall of the building is suitably insulated. The outside of the rock wool boards are, in the case of cavity walls, covered with a more solid finishing material that is wind and damp resistant. 

If you need help with all things temperature measurement, trace heating, and fireproof wiring, contact our team of expert trace heating suppliers at TRM today. 

Importance of calibrating a thermocouple

Posted on by Scott Hackett

Industrial temperature measurement can be done in a range of different ways. Thermometers are often used as a means of measuring temperature, but in situations where precision is essential and even the slightest spike needs to be recorded, advanced measurement devices like thermocouples are used. 

These temperature sensors can pick up on very subtle changes, which is why they are often used in applications where perfect accuracy is extremely important. However, like with any measurement device, the efficiency of thermocouples will deteriorate over time when constantly used. Therefore, they will occasionally require recalibration. 

What is thermocouple recalibration? 

A mineral insulated thermocouple cable contains two dissimilar wires that are welded on one side and free on the other. When the wires encounter a difference in temperature, a voltage is created, leading to a possible difference at the junction. This voltage at the junction is measured and corresponded with the temperature. 

Thermocouples are designed to be rugged and robust, so they can easily withstand various temperatures. However, because temperature measurement relies on the voltage, regular thermocouple calibration is required to make sure the device can correctly recognise the voltage. The calibration process involves comparing the measurement accuracy of the thermocouple against a known and standard reference. 

How to calibrate a thermocouple 

Calibrating an MI thermocouple takes specialised equipment and there are three main ways to do it. 

Thermodynamic fixed-point calibration 

This method is the most accurate way to calibrate a thermocouple. It entails comparing the thermocouple’s temperature readings against the widely accepted, fixed temperature points of common elements and compounds where they alter their physical state. For example, the freezing point of metal, such as tin is 231.928 degrees Celsius according to the ITS-90 (International Temperature Scale) that was introduced in 1990. 

Maintaining the reference junction at 0-degrees Celsius, the thermal EMF (electromotive force) from the thermocouple is measured at the fixed-point transition where the metal materials change from a solid to a liquid. The EMF is then compared with standard measurement charts to check the accuracy of the thermocouple’s measurement. 

Stirred bath or furnace method 

The option between a stirred bath or furnace is determined based on the temperature requirements. When the temperature reaches the optimal level, the thermocouple that needs calibrating is used alongside a known accurate thermocouple. If the first thermocouple needs calibrating, they will both show different readings. This method is carried out in a lab, but it not as accurate as thermodynamic fixed-point calibration. 

Dry block calibrator 

This method utilises a dry-block machine, with the thermocouple probes being inserted into the dry block. The metal block is then cooled down or warmed up to a certain temperature and the thermocouple readings are measured. If the thermocouple displays the same temperature set in the dry block, it doesn’t need calibration. However, if the measurements vary, then calibration might be due. 

How important is calibrating thermocouples? 

Thermocouples are crucial parts of a system that closely measure a physical property. It is expected that these temperature measurement devices perform without compromise because an error or inaccurate reading could potentially lead to a catastrophe. In different industries and applications, thermocouples can be subjected to different temperatures all day every day for months on end. 

General guidance is that calibration for every thermocouple should be done annually. However, for thermocouples that see particularly heavy use, calibration should be completed a shorter intervals.  

When constantly used, the efficacy of a thermocouple deteriorates over time. So, it is essential that calibration is made to ensure the thermocouple works smoothly and efficiently. Additionally, in some cases, companies or applications might need to have a calibration certificate due to certain regulations. 

  If you need help with thermocouple calibration or anything else relating to industrial temperature measurement, contact TRM today. 

  

Can you use heat trace on PVC pipe?

Posted on by Scott Hackett

Trace heating cable can be used on pipes made of plastic, but it’s important to take into account the plastic’s durability and thermal properties first. Plastic is 125 times more resistant to heat than steel, but it is also more vulnerable to damage from high temperatures. The key thing when heating plastic pipes is to use a lower temperature and spread it out as evenly as you can, so all the heat isn’t focused in one place.

It is always beneficial to use electric trace heating products that have an automatic thermostat and control, but this is particularly the case when using heat trace on PVC pipe. An automatic heat trace control can check and control the temperature of the system, alert you to any problems, and turn off the heat cable to avoid any damage.

There is heat cable on the market that is specifically designed for use with plastic pipes, thanks to it being self-regulating and having a limited wattage. Self-regulating heat cables include a conductive core in the middle of two bus wires that become increase in conductivity when they’re cold. This system adds more power to the cold spots and limits it in the warmer parts, which creates a more even heat source.

The manufacturer of the plastic pipe should be able to give you more information regarding the maximum temperature it can withstand and how close the heat cable can be spaced or wrapped onto the pipe to avoid any deterioration. Certain applications might need heat cable to be added to opposite ends of the pipe at a lower temperature to spread the heat more evenly, and to prevent one direct area of focused heat which could seriously impact the pipe.

It is recommended that you put in place a foil material between the pipe and heat cable to stop any direct contact and help to offer better distributed and even heating. If you go down this route, put the heat trace control thermostat directly onto the pipe with no foil over the top of it or between it and the pipe to help achieve a more accurate temperature reading.

To answer the overarching question of this article, yes you can use heat cable on plastic pipes as long as you take care and follow the precautions. These include understanding your pipe’s thermal capabilities, choosing a self-regulating, low wattage heat cable, and using an automatic heat trace control with safety functions. By following these guidelines, you can avoid damaging your heat trace system and extend its lifespan.

How can TRM help?

If you’re looking for help with trace heating UK, our team at TRM can help. As professional and experienced trace heating suppliers, we can explain how an effective trace heating system is used to compensate for heat loss, using an electrical heating part, which is put in physical contact with the surface of pipelines, vessel, tanks, etc.

This will help to ensure your manufacturing is working as it should be by maintaining or increasing temperatures where needed. Contact us today to find out how we can help you with your trace heating and general temperature management in your operations.

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