Plate heat exchanger is an important part of heat exchange technology in process industrial equipment. The elastic gasket which seals between the plates is a kind of vulnerable part and is easy to aging under natural conditions. Its service life has an important influence on the service life of plate heat exchanger. If the seals are heat hardened and the original elasticity is lost, the heat exchanger will not work properly.

1. fixing of seal:

In principle, the seal fixing is divided into two categories: bonding and non bonding. The shape of the gasket shall be consistent with the shape of the plate heat exchanger seal** It is pointed out that the bonding method does not have any effect on sealing function.

(1) Non bonding seal

Alignment: place the sealing ring in place: make the sealing ring enter the sealing groove correctly and press tightly: in the sealing groove, there is a groove structure with decreasing cross-section to make the sealing ring correctly positioned

(2) Adhesive seal

According to the purpose of use and the requirements of sealing quality, the mixed sealant and non-conforming sealant from different manufacturers can be used. Before bonding, the residual adhesive and the remaining gasket shall be removed thoroughly by steam flow. For the mixed sealing adhesive, use the fire to burn out the residual adhesive and residual gasket on the joint surface of the plate heat exchanger. When bonding in large quantities, liquid nitrogen pool of frozen seal shall be prepared, and a heating furnace with dry treatment for plate heat exchanger with sealing gasket shall be prepared. The heating temperature shall be 160 ℃, if there is any condition, chemical cleaning shall be carried out for plate heat exchanger to ensure that the sealing gasket of adhesive parts remaining in the joint surface of plate heat exchanger is completely removed.

2. replacement of seal:

(1) Inspection and detection of reuse performance. Check the wall thickness of heat exchanger and pipe in case of suspected corrosion.

(2) Clean the aged seals, and clean them with acid alkali cleaning tank according to different dirt. The surface of the cleaned parts will not be damaged by the corrosion of chemical medium (such as gasoline).

(3) After chemical cleaning, the chemical media remaining on the surface of plate heat exchanger should be completely removed by high pressure blowing device.

(4) Each heat exchanger plate is coated with fluorescent testing agent, and under ultraviolet light, check whether there are any small cracks and corrosion holes, and clean them again. In addition, the sealing groove should be inspected and repaired if necessary.

(5) For adhesive gasket, the residual substances will be completely removed, and then re bonded with the mixed adhesive, and the combined heat exchanger plate group is clamped in the special clamp to make the adhesive solidify; Heat and heat the heat preservation in the heat preservation furnace to achieve the adhesive effect of * *. For non bonding gasket, different devices are used to fix the gasket in the heat sink.

(6) The bonding position and bonding quality of each plate radiator are inspected, classified according to the installation sequence, and then the panel radiator group is carefully assembled.

The sealing gasket of plate heat exchanger determines the service life of plate heat exchanger. For large number of heat exchanger, plate plate will not be damaged generally, and the gasket will easily aging and cause leakage. Therefore, the quality of gasket determines the quality and service life of heat exchanger.