Mixed Gaskets for Plate Heat Exchangers

Introduction

Your Plate Heat Exchanger (PHE) is experiencing a leak or clog, and you don't have the flexibility in your schedule to slow down production. While you can not continue to use a plate in this condition due to the risk of a differential leak, waiting for new materials to be purchased can be costly and lead to equipment downtime. What if there was a solution that used the materials you have on hand to fix that faulty gasket? Well, there is! This is referred to as a mixed gasket solution. This solution can also be used when working with fluids incompatible with your current gaskets.

Plate Design

When mixing gaskets, you must first understand the plates' design. There are two different corrugations in the plate pattern. These patterns are called H and V or F and G. Additionally, a plate can be rotated 180° to create a right and left-hand plate. Here are the examples of the four possibilities of H and V plates:

Notice that the "hand" is referenced to the port, which allows the fluid to flow on the plate surface. The first gasket is left-hand H because the fluid flows from the left ports. Again, gaskets are symmetrical; therefore, they can be flipped 180°  to determine their orientation. The right-hand H plate is simply the left-hand H plate rotated. 

Gasket Sections

Gaskets have three sections: the periphery, bridge, and port. The port and bridge ensure the flows are correctly directed through the unit. Additionally, the gap between the port and bridge is a section that allows exterior leakage before cross-contamination should a gasket fail in any of the two sections.

In some instances, the fluids are not compatible with the same gasket material, and in those cases, we can offer a mixed gasket solution. This can easily be achieved because of the three sections in the gasket.

Mixed Gasket Solution

Based on the nature of the flow design of a plate and frame heat exchanger, we know that the fluid, as it travels through the length of a plate, will only contact the periphery of material "A" in one plate and port of the same material "A" on the next. We must cut the ports away from the periphery to achieve this sequence. Once cut, the gaskets can be mixed to provide each fluid with a compatible material. Depending on the model, gaskets can be either Loc-in or Glue-in.

Step 1: Select two gaskets to be mixed and remove them from the plates.

These two gaskets will be made of different materials that are compatible with different fluids. Keep in mind that left and right-hand gaskets are the same gasket, except one has been rotated 180°

Step 2: Cut Ports Away from the Periphery

Step 3: Mix the Gasket Sections 

 This provides each of the fluids with a compatible material.

Step 4: Re-Attach Gaskets Onto the Plates

 Depending on the model, gaskets can be either loc-in or glue-in

Reminder

It is extremely important to know the flow pattern of the unit. As a standard, the hot fluid travels through ports 1 and 4 - the left-hand side of the plate heat exchanger - while the cold fluid travels through the right-hand side. In other words, assuming a standard configuration, on a left-hand plate, the periphery material must be compatible with hot fluid, while on the right-hand plate, the ports must be of the same material as the periphery of the left-hand plate.