The GLH-75 shell and tube heat exchanger structurally adopts a combination of a detachable fixed tube sheet and a U-shaped tube bundle. During maintenance, the tube bundle can be pulled out without cutting off the shell side. Compared with the floating head type, this model reduces internal sealing points and lowers the risk of leakage; compared with plate heat exchangers, it allows particulate media to pass through, and the cleaning cycle can be extended. Design and selection personnel need to pay attention to the following maintenance-related parameters.
The tube bundle length of the GLH-75 is 2.5 m, and 1.8 m of tube extraction space is reserved at the end of the equipment. If on-site space is insufficient, a structure with a head removal ring can be selected, but the tube bundle still needs to be extracted in sections. For cleaning, high-pressure water jets are recommended, with pressure not exceeding 50 MPa, to avoid damaging the tube walls. Compared with fixed tube sheet heat exchangers, this model does not require breaking the shell connection for cleaning.
This model is suitable for a temperature difference range of -20°C to 150°C, and thermal expansion is absorbed through the free end of the U-shaped tubes. During maintenance, the welds connecting the tube sheet and tube bundle need to be inspected quarterly, with emphasis on observing whether there is corrosion thinning. Compared with floating head heat exchangers, the GLH-75 eliminates the floating head stuffing box and reduces the frequency of regular replacement of sealing components. If the medium contains chloride ions exceeding 200 mg/L, duplex steel tube bundles are recommended.
The recommended major overhaul cycle for the GLH-75 is 24 months, with minor maintenance every 6 months. Compared with detachable plate heat exchangers, its gasket replacement frequency is lower, but the single maintenance man-hours are longer. In terms of spare parts, it is recommended to keep one set each of tube bundle sealing rings and end cover gaskets in stock. During design and selection, the cost of downtime needs to be evaluated: if production does not allow long downtime, two units operating in parallel alternately can be considered.
Compared with plate heat exchangers, the GLH-75 is suitable for media with a solids content higher than 5%, but its heat transfer coefficient is lower. Compared with heat pipe heat exchangers, its pressure-bearing capacity is higher, reaching up to 2.5 MPa. Designers should make a comprehensive judgment based on medium cleanliness, temperature difference, and maintenance access dimensions. If frequent cleaning is required, a modified structure with an online backwashing interface can be selected.
