Problems with the installation of plates in plate heat exchangers

I didn’t encounter the first issue, so I don’t dare to make random comments. As for the second issue: modern plate heat exchangers generally use non-stick clamping gaskets; there is no glue involved, which makes them easy to clean. If you have a high volume of cleaning required, it’s best to replace the heat exchanger with one that uses non-stick clamping gaskets

For the first issue, alkaline water can be considered, but it shouldn’t be too concentrated. Otherwise, use butyl acetate. The general situation is basically taken care of. Remember to rinse it with water. I haven’t experienced the second one, so I won’t give an opinion

For microorganisms (slime), sodium hydroxide or sodium carbonate solutions (concentration 4%, maximum temperature 80 degrees) can be used for cleaning. For oil residues/asphalt/fats, etc., aliphatic solutions or naphtha solutions can be used for cleaning; it is absolutely forbidden to use compounds of the same type (propyl ethers, butyl ethers, methyl isobutyl ethers), esters (ethyl acetate, butyl acetate), or aromatic compounds (benzene, toluene), as these may corrode the gaskets. Residual glue in the gasket groove can be removed using acetone. If possible, it is best to replace the heat exchanger gaskets with surface-adhered gaskets.

Using a wire brush for cleaning can easily lead to the formation of scale, but failing to clean with it means that dirt cannot be removed. Therefore, I think it’s necessary to use a brush; otherwise, the heat exchange efficiency is very low, resulting in higher costs for electricity and water usage. These expenses can even be higher than those associated with replacing the heat exchange plates. Moreover, sometimes the heat exchange efficiency isn’t sufficient, which affects the quality of the product. For the second sheet, it is preferable to use a snap-fit type; of course, if glue is used, soak it in warm water. If the rubber is to be reused, the process needs to be carried out slowly. There are many types of rubber pads; some are oil-resistant while others are not. If those that are not oil-resistant get soaked, it will cause the rubber to age and swell, rendering it unusable. Therefore, ask the manufacturer before getting them soaked.

Hehehe, the plate heat exchangers you’re talking about are completely outdated; these days, there are no more ones that are glued together. I’m not sure if the heat exchanger plates you use are made of titanium. If they are, soak them in 10% dilute hydrochloric acid for half an hour, and then they can be cleaned using a regular plastic brush. It’s best not to let the heat exchanger plates dry out, as the dirt on them becomes very difficult to remove once they do. Here, the heat exchangers I have are kept submerged in water until they’re completely clean before being used again. Today’s plate exchangers all come with gaskets, which is very convenient

There’s not much that can be done for the first problem: without kerosene, one can use another type of detergent to create bubbles, but the effect isn’t very good; or one can try using alkalis or acids instead

Simply clean it with dish soap and water, scrub it with a large nylon brush, and finally wash it with a high-pressure water gun (similar to car washing); it’s fast and effective, and there’s no need to remove the rubber strips. Experience speaks. It can’t be washed off anymore; contact Engineer Zhang: QQ 420084989

Apart from nitrile gaskets, oil has a significant impact on the aging of rubber. Below are some methods I’ve gathered; they have a somewhat bookish feel, but they’re not actual books – they’re just summaries, haha! I. Maintenance of plate heat exchangers The precautions for disassembling and inspecting plate heat exchangers are as follows: a. Before disassembling the plate heat exchanger, the compression length of the plate bundle should be measured and recorded (this dimension should be used when reassembling it). b. If the gasket is stuck in the groove between the two plates, it must be carefully separated using a screwdriver. The screwdriver should be inserted at the area where it is easiest to separate the gasket, and then used to separate it along its edges; care must be taken not to damage either the heat exchanger plates or the gasket. c. When replacing the new gasket, propylene or other similar organic solvents should be used to clean the grooves of the gasket. Then use a brush to apply the synthetic resin adhesive evenly in the grooves. d. Check the heat exchanger plates for any perforations; this is generally done using a 5x magnifying glass, and sometimes light or kerosene penetration tests can also be used to inspect each plate individually. e. If debris is found accumulated in the short pipes and passages at the media inlet and outlet, it indicates that the filter has failed and should be cleaned promptly. f. There are three methods for cleaning the plates: backflushing (cleaning without disassembly), manual cleaning (cleaning by disassembly), and chemical cleaning (cleaning without disassembly). (1) Manual cleaning method. When the scale thickness on the heat exchange plates is very thin and insoluble in water, the plates can be disassembled, and each plate can be cleaned by spraying with pressurized water (0.1–0.2 MPa) or low-pressure steam containing water. For deposits that are difficult to remove using water, soft fiber brushes or bristle brushes can be used for cleaning. (2) Chemical cleaning method. On the surface of the heat exchange plates, especially in the areas where the fluid flows slowly, there are hard deposits (oxides or carbides) that are difficult to remove by manual cleaning methods; different chemical solvents can be used for cleaning, depending on the material of the heat exchange plates. g. When scaling occurs on the heat exchange plates, it is absolutely forbidden to use wire brushes or bristled brushes for cleaning, especially on stainless steel plates, to prevent accelerated corrosion of the plates. If there are stains or rust on the plate, they can be removed using cleaning powder. h. The clean water used for washing must be free of salts, sulfur, and other components. i. After the heat exchange plates are cleaned chemically, they must be rinsed thoroughly with clean water, then wiped clean with fine gauze, and stored in a clean place for later use. j. When removing titanium plates, it is strictly prohibited to expose them to open flames to prevent oxidation. k. Check the sealing gaskets for defects such as aging, deterioration, or cracks; it is prohibited to use hard objects to scratch their surface. l. Solid particles such as sand and iron slag must not accumulate on the surface of the gasket and the heat exchange plates (within the grooves). m. Check whether the heat exchange plates are locally deformed; if the deformation exceeds the allowable limit, they should be repaired or replaced. II. Reassembly of plate heat exchanger components The precautions for reassembling plate heat exchanger components are as follows: a. Before reassembling the components, it is necessary to clean thoroughly all parts such as the qualified heat exchange plates, gaskets, end caps, clamping bolts, and nuts. b. Before bonding the gasket to the groove, the residual adhesive in the groove must be melted using acetone or other similar organic solvents, and then the area should be cleaned with fine gauze. c. Use a bristle brush with a width matching that of the gasket groove to apply the synthetic resin adhesive into the groove of the plate, then press in the gasket, flatten it with a flat steel plate, and leave it there for 48 hours. d. Use propylene glycol or other organic solvents to dissolve the residual adhesive material that has been pushed out of the grooves, and remove it completely. e. When replacing the new gasket, carefully check the positions of the four corner holes in the new gasket; they must be the same as those in the old gasket. f. If one plate of a flat-plate heat exchanger is damaged and there are no spare parts, this plate along with the adjacent plate can be removed simultaneously, after which the clamping bolts can be tightened. g. When reassembling the umbrella plate heat exchanger, the plates should be rotated 180° alternately and stacked on top of each other; misinstallation is not allowed. The repaired and replaced plates shall be added to the plate bundle in accordance with these requirements. If a plate is damaged and there are no spare parts, the adjacent plates can be removed simultaneously. To determine whether the plates have been installed incorrectly, one should check the triangular markers at the center of the plates; as long as the reverse (▽) and positive (△) markers are alternately arranged there, the plates are not installed wrongly. h. The clamping bolts should be tightened evenly, symmetrically, and in a cross pattern. The clamping bolts must be tightened until the length of the plate bundle reaches the calculated dimension. i. To prevent the gasket from sticking to the plate, a layer of mixture can be applied to the gasket. The ratio of oil, alcohol, and talcum powder used in the mixture is 1∶1∶2 by weight.

Adhesive-free hanging pads indeed perform better than adhesive gaskets, but boards with too small a surface area cannot use adhesive-free pads, such as those in instrument coolers

This post was last edited by Yangxian Renjiaren on 2013-4-26 at 14:24. Although you dislike those who promote chemical cleaning agents, I still have to say that for the first issue, using just a brush isn’t sufficient; chemical cleaning agents are necessary for the plates of plate heat exchangers. Our company has developed a new product that requires less cleaning time and has a simpler cleaning process. If you’re interested, feel free to contact Wang at 013906156190. Of course, it’s fine if you don’t make a purchase after getting in touch; we can discuss things as peers in the industry, and we might even become friends.