A Simple Way to Keep Up with Temperature Calibration Standards for Thermometers

A Simple Way to Keep Up with Temperature Calibration Standards for Thermometers

If your company deals in pharmaceutical or food/beverage manufacturing, then you are most likely aware that there are stringent standards to keep up with in regards to the temperature measuring instrumentation in your facility.

Traditional methods of calibrating temperature instruments to meet standards can be cumbersome and time consuming. These standards include requirements from organizations like NSF, USDA, 3A, NIST, and now FSMA (Food Safety Modernization Act), which is a FDA reform and now mandatory to follow.

Ice Bath: An age old way of testing your thermometer’s accuracy is by placing the stem in an “ice bath.” Most people do this by filling a glass to the top with ice and slowly adding cold water, ensuring the water stays about 1 centimeter away from the top of the ice. Once the ice has been stirred and set for a couple of minutes, you place the stem of the thermometer in the center of the glass.

The preciseness behind preparing a properly made ice bath is critical to ensure your thermometer is being calibrated accurately. If your method fails to keep the bath at 32 degrees Fahrenheit, your bath can be off by several degrees deeming your calibration insufficient all together. Some other risks involved in the ice bath method are maintaining accurate ice to water ratio, ensuring your water has been rid of any dissolved minerals that could affect your freezing point, and holding your thermometer at a correct angle for accurate calibration.

Boiling Water: Another traditional method for testing your thermometer’s accuracy is by using boiling water. Once the water is at a rolling boil, the stem of the thermometer is placed into the water for one minute. While the thermometer is still immersed in water, the dial needs to be adjusted to the temperature listed in that manufacturer’s instructions.

As I’m sure you can guess, this method is a somewhat dangerous way of calibrating your thermometer as the potential for burn injuries are present. There are also many important steps you have to take to ensure your water is at a proper boiling point for your area. If you are not using distilled water or boiling at the appropriate temperature for your location, the atmospheric pressure in your area may skew your reading by as much as 5 degrees.


New & Reliable Method

If you are past using traditional methods and are looking for an easy-to-use tool for calibration, Tel-Tru Manufacturing makes a series of “Check-Set Calibrators” that are compliant with regulatory requirements and meet manufacturers’ recommendations.

Check-Set:  A Check-Set is a highly accurate, portable, NIST certified calibrator that will test a thermometer’s accuracy by +/- 0.2 degrees Fahrenheit. It comes in three separate series (I, II, IV) designed for your desired set point(s) needed for calibration. The labor behind using one is quite simple, too.   Depending on the temperature you’re trying to reach, the calibrator will need anywhere from 5-20 minutes to prepare for calibration. Users often keep the Check-Set units on all day though so they are ready for use on demand. Once the Check-Set is ready, you simply insert your thermometer stem into the calibrator and let it do the work.

What’s nice about the Check-Set Calibrators is they are not prone to error like traditional methods are. You do not need to worry if your water is at the right temperature for calibration or if you are at the right altitude for measuring. In addition, the result you will get from the Check-Set is far more accurate (+/- 0.2% degrees Fahrenheit) than any traditional method out there.

Features of a Check-Set Calibrator

  • Simple to use
  • Three separate series designed for your desired set points needed for calibration (I, II, IV)
  • Certificate of Calibration traceable to NIST
  • Built-in warning circuitry to alert user when unit exceeds set-point by 1 degree Fahrenheit
  • +/- 0.2 degrees Fahrenheit accuracy
  • Fit for plant quality assurance, process control, food safety, instrument calibration and service, and HACCP compliance

To learn more about Check-Set Calibrators, take a look at the spec sheet on our products page. Kodiak also offers all three series available for purchase on our website. If you have any further questions, please contact us and one of our technical specialists will be happy to assist.

Why Are Pressure Gauges Liquid Filled?

So you’ve figured out what size dial and connection you need on the gauge for your application. You even know your preference on wetted materials. But what about having the gauge dry vs. liquid filled? What are the benefits to a liquid filled gauge? Are there any negatives? Believe it or not, determining this feature can be puzzling for many customers.  Be confused no more – Kodiak will explain everything you need to know about why a gauge is liquid filled.

To put it simply, liquid filling a pressure gauge is strictly used as an inexpensive way to steady the needle and lubricate the internals of a gauge during applications with vibration. The most common fill fluids used are Glycerin and Silicone. Glycerin is used in around 95% of all liquid filling applications and is typically the “standard.” The reason these fluids are used is because they’re more viscous and their thickness helps keep the needle steady. Some gauges come dry but can be filled simply by filling the hermetically sealed gauge case through the fill port (usually at the top) and then reinserting the fill plug when finished.

As with any decision making, you should outweigh your pros and cons when deciding what’s right for you. Let’s break that down for you here:

Benefits of a Liquid Filled Gauge

  • It steadies the needle. Without liquid filling the gauge, the needle would bounce erratically making it difficult to pinpoint where the needle is exactly pointing on the gauge
  • It’s an inexpensive solution and in many cases comes standard on a gauge
  • It helps increase the life of the gauges by dampening as well as lubricating the mechanical parts of a pressure gauge

Negatives of a Liquid Filled Gauge

  • Discoloration (darkening or yellowing) of glycerin over time due to exposure of UV rays or extreme temperature changes
  • Standard Glycerin is really only good down to 20 degrees Fahrenheit. It is not recommended for cold environments
  • Risk of leakage
  • Pressure can build up in the case due to expansion and contraction of fluid from temperature changes (usually small, 1 PSI or so) affecting the accuracy of the reading as well as bring the needle off of zero

While some of these negatives can seem like deal breakers, there are easy solutions to these issues. We’ll start with discoloration. If potential discoloration is a concern, instead of choosing Glycerin, go with Silicone. Silicone has a bigger temperature tolerance and is not as easily affected by UV rays.  Because of this, Silicone tends to keep its color longer than Glycerin.

If your application has very low temperatures of 0 degrees or below, Silicone or a mixture of Glycerin and distilled water can be used instead of pure Glycerin. Both of these fluids will allow for lower temperatures down to -40 degrees Fahrenheit.

As for leakage, this is always a risk with liquid filled gauges but the risk is very low.  The chance of leakage depends on the quality of the gauge you’re using as well as the application. If your main concern is leakage, to decrease risk, use a crimped bezel type instead of a bayonet due to the crimped bezel holding the gasket in place permanently and is less likely to come loose in the field or by human error. Again, the risk of leakage is low nowadays due to improvements in manufacturing technologies and standards.  All of Kodiak’s gauges follow ASME B40.1 standards to help ensure the gauges we provide meet the highest quality standards.

Last but not least, let’s talk about pressure build up. Pressure build up inside a gauge can happen and is very natural for a liquid filled gauge. The pressure build up (usually very minimal) can sometimes cause the needle to move off of zero and/or cause the gauge to read inaccurately + or – 2-4%.  To alleviate the pressure, burp the gauge by slightly lifting the fill plug. Once done, you’ll see the needle move back to zero.  If you’ve never done this before, see our video for a step by step guide on how to burp a pressure gauge.

If you have any further questions or would like help in finding what pressure gauge is right for you, contact us and our trusted staff will be happy assist.

Kodiak’s Custom Engineering: Differential Pressure Assembly

Let’s say you need to measure differential pressure for a high temperature gas but the gas is way too hot for a differential pressure gauge to handle on it’s own. What can you do? A customer of ours asked us that very question and our technical support team was able to come up with a unique and cost effective solution. Allow us to introduce our most recent innovation – a differential pressure gauge assembled to two cooling towers:

We know what you’re thinking. Why did we use cooling towers instead of a diaphragm seal on each side? Isn’t that usually how you get the high temperature process away from the gauge to safely read the pressure? Yes, it sure is. However, when going the diaphragm seal route, you would actually have to take the differential pressure gauge and mount a diaphragm seal with capillary to each connection. So in the case of our assembly above, you would need two diaphragm seals and capillary assemblies filled with high temperature silicone on each side of the gauge – which can become quite costly.

In a more moderate and cost effective way, Kodiak’s technical support team suggested cooling the process before it got to the gauge. With this cooling tower approach, you can install the two towers in between the gauge and the process. The way these cooling towers are designed is to dissipate the heat allowing for media to cool at an acceptable level for the gauge to handle. This installation takes 10 minutes top – and a whole heck of a lot less expensive. No fillings needed, no strings attached.

If you’re in a similar situation with a unique application and/or looking for some technical support, give Kodiak a call. We promise to provide our expertise with cost efficient solutions.

5 Reasons Digital Pressure Gauges Are Used More Than Ever

Digital pressure gauges have been around for decades, but until recently, they have become more relevant in industrial, laboratories, and testing applications than ever before.   So, why the change?

Here are a few reasons why digital pressure gauge usage has surged.

1.) Cost – The cost of digital gauges has dropped dramatically over the last 5-7 years.  In the past, one might expect to pay around $300-$400 for a standard digital gauge with basic features.  At that price, it didn’t really merit switching from mechanical gauges that could be purchased around $20.  However, now due to technology and more efficient production, digital gauges can be purchased as low as $125 for high accuracy units or as a low as $15 for a real basic digital gauge.

2.) Availability – With costs being lower and usage going up, many digital gauges are being stocked in standard configurations instead of being made-to-order.  This allows customers to have easier access and quicker deliveries on these products.

3.) Point-of-Reference Display – Its much easier to get an accurate reading by looking at a digital display instead of an analog dial.  Think about looking at a mechanical clock vs. a digital clock.  The reading is clear and concise.  There is no “fudge factor” in the reading.

4.) Special Features – Digital pressure gauges can also come with additional features like:

  •  4/20mA outputs
  • numerous scale readings
  • max and min readings
  • data logging
  • no moving parts = more durability than mechanical gauges

5.) They’re Better  – Digital pressure gauges are overall just flat out better than mechanical gauges.  They’re more accurate in most cases, readings are easier to get, 4/20mA outputs are available, and digital gauges are more durable.

One thing is for sure, digital gauges aren’t going anywhere anytime soon.

For more information on digital gauges, visit our digital pressure gauge page: Click Here

Kodiak’s KCDG15 Low Cost Digital Gauge

Kodiak’s new KCDG15 digital gauge is perfect for reading pneumatic pressure applications where higher accuracy, better durability, and clearer readability is needed over a standard analog mechanical pressure gauge.  The KCDG15 digital gauge is designed to be a better overall pressure gauge and provide a more reliable reading while still keeping the price much lower than a traditional digital gauge.

The KCDG15 is battery operated and can come in 1/8″ npt or 1/4″ npt threaded connections (other options available at request) and is 0-145 psi standard (other ranges also available).  It is battery operated and has a 1.0% F.S. accuracy with LCD display.

For further details, CLICK HERE for the product page and specification sheet.

Pressure Gauge Options For Vibrating Applications

On high vibration industrial applications, reading a pressure gauge can often be frustrating or in some cases down right impossible without the proper configuration on the gauge.  Very often, the end user may experience:

  • The indicating needle shaking back forth making it difficult to get an actual reading
  • The indicating falling off its access from the vibration
  • Damage or short longevity of the gauge due to constant wear and tear of the pressure gauge internals

In this post on the Kodiak Blog, I wanted to briefly explain a few options that can be used to help legibility of the pressure gauge.

  1. Liquid Filling – Liquid filling the gauge with either a glycerin or silicone is easily the most popular solution and least expensive.  The viscosity of glycerin or silicone makes it a thicker fluid than something water.  With the case filled with glycerin, the needle has a harder time from shaking back forth from the vibration.  This in turn steadies the needle and allows for accurate reading.  In addition to help steady the needle, the glycerin also acts as a lubricant for the internals of the pressure gauge allowing for a longer life out in the field.
  2. Dampening Movement – Getting a pressure gauge with a dampening movement is the next best option especially for those who do not like liquid filling and prefer a dry gauge.  A silicone dampener is put on the internals of the pressure gauge near the axis of the pointer.  This steadies the pointer and allows for the same outcome as if the gauge was liquid filled.  Typically a dampening movement needs to be special requested though
  3. Capillary Tubing with Diaphragm Seal – As an option for extreme vibrating applications where liquid filling and/or dampening movements aren’t enough, the pressure gauge is often mounted to a capillary tube and diaphragm seal filled system.  The diaphragm seal is mounted at the process connection.  Capillary tubing (often 5 feet in length) is connected to the diaphragm seal and on the other end of the tubing is the pressure gauge.  The pressure gauge is then typically mounted to a wall or panel away from the vibration and a proper reading can be seen.  The diaphragm seal, capillary, and gauge assembly is filled with a fluid (often silicone), to allow for an accurate reading.

For liquid filled gauge options, take a look at our liquid filled gauge page: Click Here

Pressure Gauge, Transducer, or Switch Configurations for High Temperatures Using Cooling Towers

Standard specifications of pressure instruments, whether its a pressure gauge, pressure transducer, or pressure switch, are typically limited to the high temperatures they can see without experiencing faults in accuracy or potential failures.  For example on a pressure gauge, the more common high temperature ratings are between 160F to 200F.  And on pressure transducers, the ratings can be much lower due to the electronics.

However, pressure still needs to be read on higher temperature applications.  So, what can you do as an easy solution and is relatively inexpensive?

There a various types of solutions out there, but one that is economical in price, simple to install, and can be mounted in any direction is the use of a cooling tower.  The advantages of a cooling tower are:

  • Shorter in length than using straight pipe as an extension.  Due to the Cooling Tower’s design, it allows for the heat to dissipate over a shorter length than a straight pipe would.  This is great for space saving as well as stability of the instrument.
  • No pre-filling of water like you would have to do with a siphon.  The cooling tower is just plug and play.  Screw it into the process, put the instrument on the other end, and you’re good to go.
  • It can be mounted to a diaphragm seal for added protection. For applications using thicker medias that solidify at cooler temperatures or for high temperature corrosive applications, the use of a diaphragm seal is necessary.  A cooling tower can act as a temperature barrier between the seal and the instrument allowing for accurate readings and eliminating clogs or corrosion of the instrument.
  • Economical in price.  With the features, durability, and accuracy a cooling tower can provide, it is certainly a great price conscious option.

The photo provided above is an example we did at Kodiak using a cooling tower and mounting it to a diaphragm seal.

Here’s a link to the specification sheet of a cooling tower to show the temperature ratings, sizing, and limitations.

Level Measurement For Corrosive Or Acidic Liquids

Measuring level for liquids, especially for corrosive and acidic applications, is not always cut and dry.  Due to the caustic tendencies of the fluids, certain materials such as PTFE, CPVC, PVDF, etc. need to be used.

Going the traditional route of using a float level transmitter or a capacitive level transmitter coated in PTFE or another chemical resistant material is certainly a good option.  However, these tend to be very expensive and often don’t come with local indication if that’s desired by the end user.

Another good option is to use a non-contact type level transmitter that uses ultrasonic technology.  These instruments can be very accurate, have no moving parts, and can give the desired level readings.  However, if the media gives off vapor or fumes, which acids can often do, the ultrasonic sound waves won’t reflect back to the transmitter properly causing a false reading.

As a lesser expensive option, pictured in this blog is a level gauge Kodiak recently custom designed for a customer of ours who was trying to measure level of hydrochloric acid (HCL) in a 12 foot tank.  Due to the height of the tank, we could utilize the atmospheric pressure by measuring the level using a 0-5 psi pressure gauge.  However, because of the corrosive properties of HCL, we used a CPVC/PTFE diaphragm seal to isolate it from the gauge.  Then per the customer’s specifications we assembled the gauge to a 2″ CPVC isolation ball valve with a 90° elbow.  Then on the other end of the valve, assembled a 2″ socket by 2″ NPT connection to be screwed into the bottom the tank.

By using this custom level gauge, the customer can now accurately measure the level of the tank locally and relatively inexpensively compared to the other options.  If a 4/20mA output is needed, a low pressure transducer can be used instead of the pressure gauge for future applications.

Consolidate Instruments And Eliminate Potential Leaks By Using Manifolds

The use of manifolds on any application is a great way to consolidate instrumentation and valves into one location.  This not only saves space but also help eliminate potential leak points on the application.  Below is a picture of a perfect example of an application using multiple valves and tubing,which not only is cluster of tubing and connections, but also a potential problem of leakage.

To solve this, a manifold was designed which not only consolidated the valves into one area but also saved the customer in cost and labor.  An example of a manifold valve is below:

You can also design manifolds to not only hold valves but also other types of measuring instruments such as pressure transducer, switches, meters etc:

For more information on manifold valve designs and customization for your application please contact us by clicking HERE.

 

How To Use Diaphragm Seals On A Differential Pressure Gauge

For differential pressure applications with caustic or thick medias, mounting a differential pressure gauge directly to the process can be detrimental to the integrity of the gauge.  The wetted material of the gauge may corrode away or the differential gauge could potentially become clogged.

A solution to this problem would be to isolate the wetted parts of a differential gauge by mounting diaphragm seals made of a compatible metal or plastic to the inlet and outlet sides of the differential gauge.  However, unlike a standard pressure gauge with one port, you cannot mount a diaphragm seal directly to the differential gauge because the ports of the gauge are typically too close together to accommodate the size of the diaphragm seal.

A solution to this is to install capillary tubing in between the gauge and the diaphragm seal.  This allows for flexibility during installation, safety from high temperatures or vibration, and room for the diaphragm seals to fit on the gauge.  The entire assembly is a filled system just like a standard gauge mounted on a diaphragm seal.  The air is evacuated from the assembly and replaced with a fluid (usually silicone or glycerin).

For more information on differential gauges and/or mounting instruments to diaphragm seals, please click here to contact us.

How To Prevent Pressure Gauges, Transducers, or Switches From Clogging

A pressure instrument by itself typically has a small orifice for the media to enter into it for measurement.  This works perfectly fine for applications such as water, air, or oil measurements.  But what do you do if the media has solids in it, is thick, and/or solidifies when it cools that can potentially clog the pressure instrument rendering it useless?

The answer is mount a diaphragm seal to the instruments.  A diaphragm seal is specifically designed to be a barrier between the media and the pressure instrument.  Pressure gauges, pressure transducers, and pressure switches can all be mounted to diaphragm seals (or gauge isolators as they’re sometimes called) through a “filling process” creating a sealed system between the instrument and the seal allowing for the utmost accuracy.

There are many kinds of diaphragm seals and all are used based on what fits best for the application.  Some types include:

  • Mini Diaphragm Seals

  • Large Diaphragm Seals

  • Plastic Diaphragm Seals

  • Flow-Through Diaphragm Seals

IMPORTANT: You cannot simply screw on a diaphragm seal to a pressure instrument.  As mentioned above, it needs to be a filled system.  Essentially the instrument is mounted to the diaphragm seal.  Then air is evacuated from inside the connection and replaced with a fill fluid such as glycerin, mineral oil, or silicone.  This allows for an accurate reading.

For more information on diaphragm seals or the mounting process, please email us at kodiak@kodiakcontrols.com

 

How To Protect A Pressure Instrument From Pulsations Or Pressure Spikes

In certain applications, it is often unavoidable to experience pressure spikes.   // read more