Plate heat exchanger gasket is an important part of the chiller plate heat exchanger.The ring is made of a plastic deformation and a certain strength material. Most of the PHE gaskets are cut from non-metallic plates or made by professional factories in the specified size.Then heat exchanger gasket material consist of asbestos rubber sheet, asbestos plate, and polyethylene plate etc. Sometime it use thin metal plate (white metal or stainless steel) wrap asbestos And other non-metallic materials together and make of metal gasket.There is another kind of spiral wound gasket made by thin steel belt with the asbestos.. Ordinary rubber gasket is use for the temperature below 120 ℃ ,asbestos rubber gasket is suitable for water vapor temperature below 450 ℃,oil temperature below 350 ℃ and pressure is less than 5MPa, Commonly acid asbestos board is used for the general corrosive Medium。
According to the heat transfer medium flow, heat exchange plate is divided into unilateral flow and diagonal Correspondingly, the PHE gasket is divided into unilateral flow and diagonal Flow.
Unilateral flow means to the heat transfer medium is flowing from the right corner hole and flows out from the right corner hole of the heat exchanger plate.Similarly, the heat transfer medium is flowing from the left corner hole finally flows out from the left corner hole. Diagonal flow means that the heat transfer fluid flows from the right corner hole and flows from the left corner hole, or the fluid is flowing from the left corner hole and flows out of the right corner hole,then it’s showing a diagonal flow pattern. In terms of heat transfer efficiency, the diagonal flow scheme is better than unilateral flow,but the cost of unilateral flow is lower. Therefore, unilateral flow is generally used if it can satisfy the heat transfer efficiency.
Heat exchanger gasket types can divided into three forms according to the installation of PHE gaskets in the exchange plate.
(1) Direct glue type:Directly attached to heat transfer plate installation groove after daubing glue on the plate cooler gasket
(2) Snap on type:There are strong plastic nails along the PHE gasket edge, press the buttons into the relevant holes in the PHE plate, then the gasket is snapped on. The gasket structure is slightly more complicated than a glue fastening type but it is easy to remove and re-gasket.
(3) Clip on type, Channel plate gasket is attached to the heat exchanger plate by two gasket prongs which slip under the edge of the heat exchange plate to hold the gasket securely in alignment in the gasket groove.
For the above three forms,The glue type gasket structure is simple and easy to process but difficult to install and remove. Snap one and clip on type heat gasketstructure is complex but easy to install and remove.Heat exchanger gaskets can divide into symmetrical and asymmetric shape according to the shape of product profile.symmetrical shape is generally used in diagonal flow PHE plate.It can be installed in positive and negative position because the upper and lower sealing surface are flat and horizontal.The sealing surface of asymmetric shape rubber gasket can be flat, curved, slope and so on.