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Heat exchangers are key to temperature control for the proper melting, molding, and cooling of plastics. They allow heat transfer between different fluids so that you can control temperature throughout the process. This means consistent product quality and maximum production efficiency. There are many types of heat exchangers, but here are some of the most common for plastics processing applications.
Shell and Tube: A bundle of tubes in a shell for efficient heat transfer between two fluids. Versatile for many applications.
Plate Heat Exchangers: Multiple thin plates with channels for fluids. Large surface area for quick heat transfer. Compact and efficient. Great for space-constrained applications.
Air Cooled Heat Exchangers: Uses air to cool the fluids. Often used when cooling is needed.
Spiral Heat Exchangers: Suitable for high-pressure and high-temperature applications. Compact design and efficient heat transfer.
Pressure testing
Here at Arlington Machinery, we can pressure test all kinds of heat exchangers both Hydrostatically and Pneumatically on-site in our machine shop. This kind of test is performed to verify the integrity and safety of heat exchangers, both during manufacturing and maintenance. It will determine if the heat exchanger can withstand the operational pressures it will encounter.
During a pressure test, you will confirm things like structural integrity, any leaks in the tubes, sheet joints, and/or gaskets. Leaks reduce heat transfer efficiency, so it's essential to make sure that a pressure test is performed on a heat exchanger for not only safety reasons but also from a performance standpoint. Many times, a pressure test will reveal an impending failure that would have taken place during production operations. Hence, these tests are a good way to reduce downtime and correct defects before they cause an interruption on your factory floor. There are two primary methods used for pressure testing heat exchangers.
Hydrostatic Testing - Filling the heat exchanger with water and applying pressure to a specified level, usually 1.3 to 1.5 times the design pressure. The pressure is maintained for a specific period (e.g., 30 minutes) to detect leaks.
- The advantage of performing this type of test is that it will use less energy because the stored energy of water compared to a gas is less, reducing the risk of equipment failure during the test.
Pneumatic Testing - Involves pressurizing the system with air or an inert gas like nitrogen. This form of test is used when hydrostatic testing is not suitable, such as for the tube side of a heat exchanger.
Pneumatic tests are inherently more dangerous than hydrostatic ones because you're dealing with compressed gases. Always make sure you are wearing proper protection and following the safety procedures.
