Spiral Plate Heat Exchanger

Spiral Plate Heat Exchanger

Spiral plate heat exchangers are a type of heat exchange equipment suitable for vapor-vapor, vapor-liquid, and liquid-liquid heat transfer of liquids. They are used in industries such as chemicals, petrochemicals, solvents, food, light industry, textiles, metallurgy, steel rolling, and coking. They can be classified into non-detachable (Type I) spiral plate heat exchangers and detachable (Type II, Type III) spiral plate heat exchangers based on their structural forms.

The spiral plate heat exchanger, proven over many years of practical use, is suitable for applications in industries such as chemicals, petroleum, solvents, food, light industry, textiles, metallurgy, rolling steel, and coking. The non-detachable spiral plate heat exchanger is designed according to the machinery department standard JB/TQ724-89 for non-detachable spiral plate heat exchangers, with specified basic parameters and dimensions. It boasts advantages such as simple manufacturing, low cost, compact size, and good heat transfer performance. However, it also has its drawbacks, such as being unable to be mechanically cleaned and being difficult to repair if damaged. Selectors should choose specific equipment based on the actual conditions of the project to ensure its effectiveness.

       Structure and Performance

1. This equipment is suitable for liquid-liquid, gas-gas, and gas-liquid heat transfer, which can be used for steam condensation and liquid evaporation heat transfer in various industrial sectors such as chemicals, petroleum, machinery, electricity, light industry, and textiles.

2. This equipment is formed by rolling two steel plates, creating two even spiral channels. Both heat transfer cutoffs allow for full countercurrent flow, suitable for heat transfer with small temperature differences. It facilitates the recovery of low-temperature heat sources and enables accurate control of the outlet temperature.

3. The transition on the housing is tangential, with minimal local resistance. The helical channel curvature is uniform, and there is no significant direction change of the fluid within the equipment, resulting in low total resistance. Consequently, the design flow rate can be increased to achieve higher heat transfer capacity.

4. The ends of the helical channel are welded for a sealed connection, offering good sealing performance and a reliable structure.

5. Not easy to repair; when issues arise with the internal panels, they are difficult to fix. Some manufacturers remove all welds at both ends of the equipment, flatten the panels and re-weld them before rolling them back into shape. This process is highly time-consuming. Given that anti-corrosion is very important for spiral plate heat exchangers.

6. Not suitable for mechanical cleaning; production practice has proven that spiral plate heat exchangers are less prone to clogging compared to conventional tube bundle heat exchangers. Silt, small shells, and other suspended particles are not easily deposited in the spiral channels. The analysis of the reasons: Firstly, because it is a single-channel deposit of impurities within the channel, a circulating flow is formed, which will increase and wash it away. Secondly, because there are no dead corners in the spiral channels, impurities are easily flushed out.

7. Due to the presence of spacer columns supporting the channel spacing within the helical channels, no fibrous impurities (cotton yarn, straw sticks, leaves, etc.) are allowed to enter the interior of the heat exchanger.

8. Strictly control the outlet temperature of the cooling water below the scaling temperature.

9. Common cleaning methods include steam blowing and alkali washing. Steam should be blown into the inlet, expelling impurities from the equipment. Many users believe this to be an effective approach.

       Detachable Spiral Plate Heat Exchangers (Type II, Type III)

The structural principle is essentially the same as that of a non-separable heat exchanger, but the channels can be disassembled for cleaning, and both ends are sealed with flanges. Particularly suitable for liquid-to-liquid exchanges involving sticky or sedimentary liquids, as well as gas-liquid and steam condensation. Due to the need for additional components such as flanges and gaskets, the equipment cost is slightly higher than that of a non-separable heat exchanger.

       Basic Parameters

The nominal pressure PN of the spiral plate heat exchangers is specified as 0.6, 1, 1.6, and 2.5 MPa (equivalent to the original 6, 10, 16, and 25 kg/cm²), referring to the working pressure of a single channel. The test pressure is 1.25 times the working pressure.

The material for the contact part of the spiral plate heat exchanger with the medium is carbon steel Q235A, Q235AF, and stainless steel acid steel SUS321, SUS304. Other materials can be selected according to the customer's requirements.

Operating Temperature Range: Carbon steel: t=0～+350°C, stainless steel and acid-resistant steel: t=-40～500°C. The temperature and pressure reduction range shall comply with the relevant regulations for pressure vessels. When selecting this equipment, appropriate process calculations should be made to ensure the fluid in the equipment passage reaches a turbulent state. (Generally, liquid velocity: 1m/sec; gas velocity: 10m/sec).

A single unit does not meet the usage requirements; multiple units can be combined for use. However, the combination must comply with the following regulations:

Parallel and Series Combinations: Same equipment and channel spacing. Mixed Combinations: One channel in parallel, one channel in series.

Stainless steel, acid-resistant PN 0.6, 1.6 MPa, non-removable (Type I) helical plate heat exchanger.