Capillary Tubing Selection Guide

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 Selecting the correct capillary tubing for your application is critical to the performance of your measurement system. The proper tube will reduce dwell time, minimize diffusion effects, maintain sample integrity, and speed up and increase accuracy of your measurement. Selecting the right length will also limit Newtonian flow in the sample loop. Here are some tips for choosing the right capillary tube for your application. Use this guide on: chromtech.com,  to make your selection.When selecting the correct type of capillary tubing for a particular application, it is important to understand the difference between the liquid and gas phases. 

 

While a capillary tube will operate satisfactorily even in the presence of a large pressure difference, it will not be very efficient. You should also consider the application's temperature. If the temperature fluctuates a lot, the tube may experience an overcharge. Overcharge will result in higher temperatures and pressure on the low side of the system.Size is also an important consideration. Capillary tubing with larger diameters offers a faster response time. However, large diameters tend to exhibit increased zero shifts in ambient temperatures, so it is essential to consider the size of your system when selecting a capillary tubing for your application. Small diameter tubing has a smaller cross-sectional area and can cause an undesirable lag time, especially if you are using a high-viscosity seal fluid.

 

The capacity of your condenser will also determine the proper capillary tube. It is crucial to choose a long tube, as this will simplify installation and avoid a complicated layout. A shorter tube will create more work for the installation team. The external diameter should match the internal diameter, since too large an external diameter will cause the condenser to fail and reduce efficiency. If you don't have an accurate gauge, you can use a sizing chart provided by the manufacturer on this site to get the correct capillary tube for your system.Every refrigerating system requires a pressure-reducing device. A capillary tube is most commonly used in small single-compressor/single-evaporator systems, but its uses may extend beyond this. A capillary tube is an excellent choice for small systems with very low refrigerant flow. However, if your system is bigger, you should also consider installing a pressure-reducing device.

A capillary tube should not be installed in a high-pressure environment, as the refrigerant flow rate will be higher when the temperature of the air is higher than the pressure of the water in the condenser. Choosing a low-pressure tube will help prevent your system from overheating and reduce efficiency. This is also important to ensure the long-term efficiency of your refrigeration system. If you're planning to install a capillary tube in a high-pressure environment, then a low-pressure capillary tube will prevent the refrigerant from overheating. You can get more enlightened on this topic by reading here: https://en.wikipedia.org/wiki/High-performance_liquid_chromatography.