Sanitary Steam Traps and the Role They Play in Temperature Validated Steam-in-Place

This video explains the role of the steam trap in successful temperature-validated SIP. Courtesy of Steriflow. Click here to watch video.

Steam trap design and operation play a fundamental role in successful temperature-validated SIP. If the steam trap does not open at the correct time and temperature to drain condensate, it can adversely affect heat-up time and whether the temperature hold is successful. It will negatively affect your revenue because of asset startup delays if it isn't.

SIP (Sterilize, or Steam In Place) is timed sterilization of the upstream and downstream biopharmaceutical production train using clean Steam. It is part of a 5 step sanitization routine that occurs after every production batch and follows the final rinse after CIP (Clean In Place). SIP ensures that every square inch of the production train that comes in contact with drug substance inputs, drug substance, or the final drug product is "sterilized" to ensure no microbiological activity in the system.

Clean Steam (made from USP Purified Water) is circulated through all of the process tubing during this stage and enters large vessels through spray balls embedded in the vessel ceiling.

SIP is a temperature-validated process, meaning that sterilization events are proven by measuring the event's temperature and recording the data. The minimum sterilization regimen requires the injection of clean Steam into all piping and vessels for at least 1/2 hour after reaching a minimum temperature of 250°F (121°C). If the temperature falls below 250°F (121°C) during the temperature hold period, a temperature validation fault gets logged, and SIP repeats.

Validation temperature sensors (usually RTD's) are placed at the condensate outlets of process equipment to ensure that the sterilization temperature meets the specific regimen designed for the process system. The sensing elements are usually designed with integral sheathes and Tri-Clamp™ connections and clamp directly to tubing tees, or the element inserts into a Tri-Clamp™ thermowell connected to the tee. The sensors usually are twelve to eighteen (12 - 18) inches (300 - 450mm) upstream of the clean steam trap where the condensate exits the piping or vessel.

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Bubbler-Tube Liquid Level System

The Type L100 is a complete and ready to use
bubble-tube liquid level measurement system.
Image courtesy ControlAir, Inc.

Measuring liquid level in an open tank or vessel can be accomplished in a number of ways, all of which require some arrangement of instrumentation to either infer the liquid level from the measurement of a related physical property, or directly deliver the liquid level visually using a scaled gauge arrangement. One indirect method of level measurement is often referred to as the bubbler or bubble-tube method, so named because it employs a purging gas that continually vents from the bottom of a tube extending into a tank of liquid. Through a simple apparatus, the level of a liquid can be inferred by the amount a back pressure exerted upon the gas flowing through the tube.

Probably the greatest advantage of this method of liquid level measurement is that the media does not contact the sensing instrumentation, protecting the instrument from damage by the media, and the media from possible contamination from the sensor. The only portion of the apparatus in contact with the liquid is a tube immersed into the tank. Basically, a purge gas flows through the immersion tube and may bubble out the immersed end of the tube, which is open to allow the contained liquid to exert a hydrostatic pressure on the purge gas. The back pressure on the gas that is exerted by the liquid contained within the tank will vary directly with the depth of the liquid. The back pressure can be correlated to a liquid level. Further calculations, which would include the tank shape, dimensions, and the liquid density can provide an indication of the volume and mass of the liquid.

It is feasible to create your own bubbler system, but the cost in human resources to design, coordinate, procure, and assemble all the components is unnecessary. ControlAir provides a completely designed and pre-assembled unit, compact and ready to run on your application. More information is included in the datasheet below. Share your process measurement challenges of all types with measurement specialists. Leverage your own knowledge and experience with their product application expertise to develop an effective solution.
 

Bubble-Tube Liquid Level System from Hile Controls of Alabama, Inc.

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.

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.

See How It Works: Magnetic Level Gauge

Magnetic level gauges, also referred to as magnetic level indicators, are routinely used to provide a display of liquid level in tanks and other vessels. They are often employed in tandem with magnetostrictive, guided wave radar, or other measurement means to provide a reliable local display of liquid level, as well as an electrical signal that can be transmitted to recording instrumentation or controllers. The favorable attributes of magnetic level gauges include:

• Continuous level measurement
• Operable without electric power
• Direct visual tank fluid level indication, regardless of tank shape or profile.
• Wide range of operating temperature and pressure
• Breakage resistant construction
• Range of construction materials available to accommodate corrosive media
• Measuring indicators, switches, and transmitters mounted externally, without contacting the medium being measured.
• Low maintenance operation.
• Readable level indication from greater distance than glass sight gauges.
• Applicable to large fluid level ranges with a single instrument.

Magnetic level indicators have a strong position in the liquid level measurement field and should be considered as a candidate for fulfilling those applications where the magnetic level gauge features fulfill the project requirements. There are many options available to customize the level indicator for each specific application. Share your application challenges with a product specialist, combining your process knowledge with their product application expertise to develop an effective solution.

Turbine Flow Meters for Process Measurement and Control

Turbine Flow Meters
Courtesy Flow Technology

Hile Controls of Alabama represents Flow Technology Inc., a manufacturer of turbine, magnetic, ultrasonic, and positive displacement flow meters utilized in process measurement and control. The company also manufactures flow meter calibration equipment, and they have summarized some useful information regarding turbine flow meters into a concise white paper, which is included below. The paper provides a description of how a turbine flow meter operates, and continues with a short narrative of turbine flow meter advantages for certain applications. Calibration procedures are also outlined, with a combination of technical and non-technical language that provides useful information and understanding to the expert and not so expert reader. Concepts are illustrated to provide additional clarity.

Browse the paper. The text portion is just a few pages. Share your flow measurement challenges with a product specialist and combine your process experience with their product expertise. That is where the best solutions come from.

Selection and Calibration of a Turbine Flow Meter from Hile Controls of Alabama, Inc.