You don’t need to be an expert technician to troubleshoot your plate heat exchanger (PHE). PHEs are long-lasting, however, they do occasionally have performance difficulties. Leakage outside the unit, leakage within the unit, and pressure drop are the three most common problems with PHEs. The majority of these problems are simple to identify and resolve.
This article will help you figure out what’s wrong with your plate heat exchanger and how to fix it. Almost all problems are caused by plate fouling or gasket failure, but it’s crucial to figure out if it’s a one-time issue or a system defect. The first step is to determine what is causing your heat exchanger to malfunction.
Identify the Symptoms
The following are some of the most common symptoms:
- Pressure drop from intake to exit is increased.
- Heat transport efficiency is deteriorating.
- Flow and performance are both affected.
- Fluid leaking in the process
The first three symptoms are usually caused by plate fouling, whereas the last one is caused by a gasket failure. However, any of the four can be caused by gasket failure or the rarer event of plate cracks, so it’s critical to take some basic procedures to figure out what’s wrong.
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Differential Leaks and Gasket Failure
When troubleshooting, it’s usually preferable to start with the most likely problem, as it has the simplest and cheapest solution. Gasket failure is the easiest thing to spot: if a gasket fails, the pressure will drive fluid through the leak, and you’ll see fluid dripping from the PHE. You’ll be able to easily detect the failure since the fluid will seep from the faulty gasket. Disassemble your PHE and remove the plate with the failing gasket as well as a plate adjacent to it. Then, if you have new parts on hand, just replace them, reassemble, and tighten your PHE to specifications before returning it to service. If you don’t have the replacement components on hand and can’t wait for them to arrive, you may simply close your plate heat exchanger and put it back into service while you wait – the loss of two plates will have a little influence on performance. However, with two fewer plates, be sure you know how much to tighten the PHE. This information should be in your manual or available from the manufacturer.
A differential leak occurs when two fluids are in a PHE mix owing to device failure. Incompatible fluids and/or high pressure are the two most typical causes of a failed gasket. Ensure that your pressures are within specifications (and that your system is devoid of potential water hammers) and that your gaskets are rated for the materials you’re using. If your gaskets are forming holes, your fluid is likely too hot or corrosive, and you’ll need to replace them with new ones that are better suited to your operation.
Damage to the gaskets or a mistake in the assembly of the unit is the most common causes of liquid leakage. Begin by measuring the distance between the front plate and the pressure plate. The unit’s instructions should have provided you with this measurement. The unit should be tightened if this measurement is larger than usual; make sure all of the bolts are tightened uniformly. Mark which plates are leaking if this measurement is accurate if the unit continues to leak after being tightened. Check the plates after disassembling the heat exchanger. In the designated plates, replace the gaskets. Our Heat Exchanger Manual contains instructions on how to replace gaskets.
Leakage From Within The Unit (Liquids Mixing)
If the liquids inside the unit start to mix, it’s because the plates inside the device are leaking. A perforated plate is most likely to blame. A pressure test can be used to verify this. Fill the unit halfway with water and pressurize one side only. The unpressurized side of a perforated plate will overflow if one exists. Apply consistent water pressure to one side of the unit to begin (NEVER use compressed air with your PHE). Fill the other side of the unit with water, but do not apply pressure on the other side. If a plate is perforated, the pressured side will seep into the unpressurized side, causing it to overflow. Each segment of a heat exchanger must be tested independently if it has two sections. Disassemble the machine if a plate is perforated and check the plates with a crevice detection liquid. The disassembly of your heat exchanger is covered in our Heat Exchanger Manual.
Corrosion and Plate Fouling
Plate fouling is the most prevalent problem with PHEs, but it’s difficult to fix because it’s not usually covered by a warranty. If your PHE becomes fouled frequently due to the qualities of your process fluid, there isn’t much you can do except clean it regularly. You can talk to your manufacturer about adding plates with wider spacing, but that solution has performance and cost limitations, and it isn’t appropriate in all circumstances. In general, the best approach is to keep a regular cleaning plan. The most convenient method is to clean in place (CIP), however, disassembly and cleaning by hand is also an option.
Corrosion of the plates is a far more serious problem than simple fouling. A differential leak is also present in this case. You can re-use your plate heat exchanger in the same way, but a cracked or corroded plate indicates that one of your fluids is excessively corrosive, and you may encounter the same issue again. Make that your PHE is correctly specified for your application by checking with your manufacturer. If everything appears to be in order, the crack or rust is almost certainly a manufactured defect that will be covered by warranty.
Heat Transfer and/or Pressure Drop Performance of the PHE is Abnormal
There are a few tests you may run to figure out why your heat exchanger isn’t performing as well, as it should. The most prevalent problem with heat exchangers is poor performance, which can be caused by a number of factors including platage errors, insufficient water flow, debris buildup inside the device, or a bad hookup.
Platage error: If the plates are joined incorrectly, a dead zone can form, leading the unit to bypass a portion of the plates. Examine the plates to make sure they’re in a honeycomb design. It can be difficult to spot the pattern change straight away, so keep an eye out for any backward plates. If a plate is out of place, you must open the heat exchanger (disassembly and reassembly instructions are included in our PHE manual) and turn the reverse plate. Close the device and test the pressure once more when all of the plates have been adjusted.
Insufficient water flows: The heat exchanger will lose productivity if the water flowing to the unit is insufficient. Check the water’s pressure and flow rate to make sure they’re within the set limits.
Debris in the unit: Debris in the unit will reduce performance. To clear out any extra debris, run a regular CIP cycle; if the debris does not go, manual cleaning may be required. Cleaning a heat exchanger by hand is pretty simple, and the Heat Exchanger Manual contains full instructions.
Faulty Connection: If the connection is incorrect, the unit will run at very low efficiency. Check the operating and setup instructions to make sure it’s working appropriately. Keep in mind that countercurrent flow is essential.
Thing to Remember
Plate heat exchangers are notoriously difficult to assemble if you don’t know the plate configuration. Please do not remove your dishes from the table without first numbering them.
If your plate heat exchanger is still not working after doing all of these tests, please give a call to Alaqua, we will do everything we can to get your system back on track! Whatever the problem, we have a solution and are always willing to assist. Contact us for further assistance!