A plate-and-frame heat exchanger is a compressed pack of thin, vertically standing, corrugated metal plates usually made from stainless steel with open ports for the passage of two fluids between which the heat transfer will occur. The plate pack is pressed together between two thick metal pressure-retaining frames and is compressed with large tightening bolts.
A plate-and-frame heat exchanger has a major advantage over a conventional heat exchanger in that the fluids running through them are exposed to a much larger surface area for heat transfer. Instead of running through a series of intertwined pipes, the fluids in a plate-and-frame spread out over the entire plate surfaces. The design theory of these systems follows this simple logic: the more contact with the metal surfaces, the more transfer of heat, and the greater the speed of the temperature change. Therefore, a plate-and-frame heat exchanger can be used to rapidly heat or rapidly cool a body of liquid.
Here is a great animated video that shows how a plate-and-frame heat exchanger transfer heat from one volume of water to another:
As long as the fluids (usually water) running through the exchanger are relatively free from foulants, debris, and hardness, a plate-and-frame heater exchanger is a highly efficient system of heat transfer. It is when they become dirty or fouled that they become inefficient, or if they become completely clogged they can become almost useless. While some fouling over time is almost inevitable, severe performance issues or even complete system failure can happen if a plate-and-frame heat exchanger is not properly maintained.
The most common issues which might cause heat exchanger failure are dependent on the type of process and the type of fluids you might be processing within the exchanger. Some common causes of plate and frame heat exchanger failure are:
- Plate imperfections
- Faulty gasket installation
- Aggressive microbiological fouling
- Improper design specifications
- Improper operating conditions
- Oxygen pitting due to improper water treatment
- Stress cracking
- Erosion corrosion due to a debris in the system
A facility that loses a major plate-and-frame heat exchanger due to failure usually has little choice but to spend what could be an exorbitant amount of money to fix the exchanger under an emergency situation. In order to avoid an emergency shutdown, many facilities create a budget for routine maintenance of their heat exchangers.
There are multiple options for cleaning a plate-and-frame heat exchanger. They include:
- Cleaning in place (CIP). This technique means that the exchanger is taken offline by way of a bypass and chemicals are used to clean/dissolve materials inside of the exchanger without taking it apart.
- On-site physical cleaning. This is usually performed by a professional HVAC Cleaning Service Company that has experience cleaning plate-and-frame heat exchangers.
- Off-site physical cleaning. This option is used when the plate-and-frame exchanger is of a type that is difficult to clean on-site. For example, an exchanger that utilizes "glued on" gaskets. These types of exchangers can be extremely difficult to properly clean on-site, especially if gaskets need to be replaced. Replacing glued on gaskets should only be done in a controlled environment where the existing gasket and glue can be correctly removed and the exchanger plate can be properly cleaned and inspected.
If your facility operates a plate-and-frame heat exchanger or multiple exchangers, you should consider adding a regular maintenance and cleaning schedule for them to your operating budget. The main benefits of a clean exchanger are two-fold:
- Reduced downtime
- Decreased fuel consumption and energy costs
The benefit of reduced downtime is obvious whether you are operating a manufacturing plant or an office building, but the benefit of lower energy costs cannot always be easily realized. It is this decrease in energy cost, however, that could add up to tens or even hundreds-of-thousands of dollars in savings in overall operations over the course of a year (depending on the size of the exchanger, fluid running through the system, and type of process).
If your facility utilizes a plate-and-frame heat exchanger and you suspect that it has not been cleaned or inspected in some time, do not hesitate to contact a reputable HVAC Cleaning Service Company in your area. As one of the best HVAC Cleaning Services in the New York City area, Clarity Water Technologies promotes a proactive maintenance philosophy when it comes to heat exchangers, and therefore, many of our customers generally enjoy lower fuel bills and reduced downtime.
If you would like some guidance on how to choose the best HVAC Cleaning Company in your area, please feel free to download our free eBook below: "Top 5 Tips for Choosing the Best HVAC Cleaning Company." If you need emergency cleaning service on your plate-and-frame heat exchanger in the greater NY/NJ area, please do not hesitate to call us at 888-616-3545.
Thanks for reading!
Greg Frazier is an expert in Industrial Water Treatment and is currently the Managing Partner of Clarity Water Technologies, a top Water Treatment and HVAC Cleaning Company in New York. He has over 18 years of Industrial Water Treatment experience and holds a degree in Chemical Engineering from the University of Tennessee.