Plate heat exchanger

Shandong Youkun Energy Equipment Co., Ltd. is a manufacturer of heat exchangers, including plate heat exchangers, volumetric heat exchangers, helical coil heat exchangers, annular heat exchangers, floating head heat exchangers, low-pressure heat exchangers, and heating heat exchangers. The company's main products include nine major categories: heat exchangers, plate heat exchangers, heat exchanger units, pressure vessels, boiler auxiliary equipment, water supply equipment, water treatment equipment, reverse osmosis devices, sewage treatment equipment, and fully intelligent oil/gas/electric boilers. Heat exchangers, plate heat exchangers, and heat exchanger units are suitable for sanitary hot water in residential areas, government offices, factories, hospitals, hotels, and schools. Integral heat exchanger units can be used for water-to-water exchange or steam-to-water exchange. For reliable heat exchanger units, choose Youkun.

I. Overview
Plate heat exchangers have advantages such as high heat transfer coefficient, compact structure, small footprint, flexible operation, wide application range, low thermal resistance loss, easy installation and use, and low investment cost. Therefore, they are widely used in petroleum, chemical, thermal power, metallurgy, light textile, food, pharmaceutical, HVAC heating, nuclear industry, shipbuilding, and marine development fields.
With the development of modern industry, the rational utilization of energy and environmental protection are the primary issues to be addressed by countries worldwide. As a high-efficiency heat exchange product in the heat exchange field, plate heat exchangers have already received attention from manufacturers at home and abroad. Our company has learned from and absorbed the advanced technologies of domestic and foreign counterparts and cooperated with universities to research and develop high-efficiency and durable plate heat exchangers with internationally advanced levels. The plates adopt a unique non-stick gasket structure, and the plate processing uses a unique process, increasing the operating pressure, operating temperature, and service life of the plate heat exchanger. We have independently developed plate types suitable for different media and flow rates, expanding the application range, significantly reducing investment costs, and improving the heat transfer coefficient. The use of industrial automatic assembly lines has improved product quality, enhanced reliability and credibility, and been well-received by users.

II. Structure, Principle, and Characteristics
Plate heat exchangers mainly consist of heat transfer plates, sealing gaskets, pressure plates, upper and lower guide rods, columns, clamping studs, and bolts. The four corners of the heat transfer plates have corner holes and are inlaid with sealing gaskets. When the equipment is clamped, the sealing gaskets seal and connect the heat transfer plates according to the process combination form. The corner holes are interconnected to form a labyrinth-like media channel, allowing the heat exchange media to flow in opposite directions in adjacent channels, conducting sufficient heat exchange through enhanced convection and conduction.
Due to the special structure of the heat transfer plates, strong turbulence can be induced at a low flow rate (Re=200) after assembly, thus increasing the degree of destruction of the fluid boundary layer and enhancing the heat transfer process.
The operating pressure of the plate heat exchanger is generally 1.0 MPa to 1.6 MPa, and the operating temperature is generally below 160°C. When used for steam heating or condensation, a desuperheating tube heat exchanger is generally added to the plate heat exchanger to cool and protect the gaskets of the plate heat exchanger and increase the steam processing capacity. The material of the heat transfer plate is generally stainless steel; the sealing gasket generally uses materials such as nitrile rubber, ethylene propylene rubber, nitrile food rubber, and fluororubber. Other materials can also be selected for the heat transfer plates and sealing gaskets according to the user's needs.
As a leading domestic manufacturer of heat exchange equipment, our main technological characteristics are as follows:
1. High Heat Transfer Efficiency
The reasonable design of the corrugated structure of the heat transfer plate is conducive to enhancing heat transfer. It can allow the medium to form a turbulent state at a lower flow rate. The use of rounded transitions in the flow path avoids dead zones, significantly reducing the possibility of fouling and achieving high heat transfer efficiency.
2. Long Service Life
The heat transfer plates use a non-stick gasket structure to prevent corrosion of the heat transfer plates by the adhesive. During the stretching and forming of the heat transfer plates, a new non-simultaneous molding process is used to ensure uniform stretching of the plates and accurate corrugation dimensions, making the corrosion resistance and mechanical strength of the heat transfer plates uniform. This extends the service life of the plate heat exchanger. The design service life of our plate heat exchangers is 15 years.
3. Good Stress Performance
Reinforced structures are used around the flow channels of the heat transfer plates; the corrugation dimensions are reasonable; and the contact points are evenly distributed. The pressure resistance is improved, and the maximum pressure can reach 2.5 MPa.
4. Low Pressure Drop
The corrugation direction at the corner holes of the heat transfer plates scientifically adopts a streamlined shape to avoid flow dead zones and increase the equivalent diameter of the flow channel.
5. Safe and Reliable Operation
The plate heat exchangers produced by our company use a double-seal structure for the sealing gaskets. Under the clamped state of the plates, the deformation is small, the resilience is good, and the sealing of the gaskets is reliable after assembly and reassembly and maintenance. There is no internal leakage in the heat exchanger, and any external leakage can be detected and handled promptly. The aging rate of the sealing gaskets is slow.

III. Installation
1. After unpacking the equipment, you should check each item according to the items listed in the delivery list. If there are any non-compliant items, you should immediately inform our company so that they can be resolved promptly.
2. The equipment is equipped with lifting rings for hoisting. Before hoisting, select the hoisting equipment according to the weight indicated on the nameplate.
3. The equipment should be installed horizontally in a place without obstruction from pipes or other equipment, ensuring a space of about 1 meter around the equipment for maintenance and repair.
4. The pump that transports liquid into the equipment should be equipped with a flow control valve. If the maximum outlet pressure of the pump is greater than the maximum pressure of the equipment, a safety pressure relief valve should be installed.
5. When installing stop valves, flow control valves, pressure reducing valves, and pressure control valves, they should be installed at the inlet of the equipment and not at the outlet.
6. Before installation, the inlet and outlet pipes of the equipment should be cleaned to prevent debris such as sand, oil, and welding slag from entering the equipment, which may cause internal blockage or damage to the plates. It is best to install a filter before the equipment inlet to prevent various impurities from entering the equipment and causing blockage. For customers in areas with poor water quality, a descaling device should be installed before the equipment to ensure the heat transfer effect of the equipment and keep it in optimal condition.
7. Sealing gaskets should be added to the pipe flanges, and the sealing gaskets should be accurately placed in the center of the flanges.
8. The water entering the equipment should be softened to improve the heat exchange efficiency and extend the service life of the equipment.
9. Bypass valves should be added to the inlet and outlet of the equipment. During the first operation of the equipment, the water in the system can be circulated and drained. After the water quality in the system meets the requirements, the bypass valve can be closed, and the system can be put into formal operation.
10. Pressure gauges should be installed on the inlet and outlet pipes of the heat exchanger to monitor the operating status of the heat exchanger and determine the cleaning time.
11. When connecting the heat exchanger interface and piping, the pipe port table in the heat exchanger drawings should be followed to avoid the heat exchanger pipe being subjected to pipe expansion and contraction stress. After installation, make proper markings.

IV. Operation
1. Before operating the equipment, check whether all bolts are loose. If loose, tighten them to the tightening dimensions first.
2. Before starting, open all outlet valves of the heat exchanger and close the inlet valve of the heat exchanger. After starting the pump, slowly open the inlet valve of the heat exchanger and gradually increase the pressure to avoid instantaneous impact and local high pressure damaging the equipment.
3. When the heat exchanger is running, to prevent overpressure on one side, the inlet valves of the cold and hot media entering the heat exchanger should be opened simultaneously, or the low-pressure side fluid should be slowly injected first, and then the high-pressure fluid should be slowly injected.
4. According to the indicators of the inlet and outlet thermometers of the heat exchanger, use the throttle valve to control the flow rate of the cold and hot fluids to achieve the required process parameters and stable operation.
5. If the heat exchanger stops for some reason, the operation steps should be carried out in the reverse order of startup.
6. When performing gas-liquid heat exchange, the gas passage side should be a single flow, and the inlet should be at the top.
7. For equipment used in the food industry, the heat exchanger should be thoroughly cleaned and disinfected before use. Hot water can be used for cleaning to remove air, oil stains, and debris from the equipment.
8. There should be air release valves in the piping system. After starting up, the air in the equipment should be removed to prevent air from staying in the equipment and reducing the heat transfer effect.
9. When the temperature difference between the two media is large, the low-temperature medium can be introduced first, followed by the high-temperature medium. In case of shutdown or power failure, the inlet valve of the high-temperature medium should be immediately turned off (the matching valve must be well sealed and not allowed to leak to prevent the gasket from aging prematurely without heat exchange under high temperature), and then the low-temperature medium should be turned off.
10. If the cold and hot media contain large particles of mud, sand, or other impurities, they should be filtered first. Do not use sewage for water pressure testing and operation to prevent affecting the service life of the equipment. (Our company specializes in producing various types of filters that match it. Please specify when ordering).

V. Maintenance
In the place where the heat exchanger is running, appropriate range and calibrated pressure gauges, sensors, thermometers, flow meters, etc., should be installed on the inlet and outlet pipelines of the heat exchanger. The operating status of the heat exchanger is determined based on the instrument readings. When the heat exchanger works for a long time, scale or sediment will be generated on the surface of the plates to varying degrees, which will increase the flow resistance and reduce the heat transfer performance. Therefore, it is necessary to formulate the operating cycle according to the actual state of the water quality or medium and conduct regular inspections and cleaning. When cleaning, mechanical cleaning or chemical cleaning can be used.
1. Mechanical Cleaning
(1) Loosen the heat exchanger, remove the clamping bolts, and move the movable clamping plate towards the support to create a certain distance between the plates, and then cleaning can be carried out. If it is necessary to replace the sealing gasket and the damaged plate, the upper end of the plate should be tilted towards the movable clamping plate, then removed from the hanging beam hanging port, and the lower end of the plate should also be separated from the lower beam, and then the plate can be removed.
(2) For some operating media in the chemical industry, due to the influence of temperature or chemical reactions, solid substances are generated. Their components must be analyzed, and appropriate cleaning agents should be configured for washing or steaming.
(3) When cleaning the plates, use a palm brush or fiber brush to brush them. Do not use a wire brush to avoid scratching the plates and reducing corrosion resistance.
(4) When cleaning the sealing gaskets, be careful to avoid scratching the gaskets.
(5) After brushing the plates, rinse them with clean water and wipe the plates and sealing gaskets clean with a clean cloth or cotton gauze, so that no solid particles remain on them.
(6) When assembling the heat exchanger, assemble it according to the process and check whether the arrangement of the plates is correct.
(7) Damaged plates and aged gaskets should be replaced.
(8) When clamping the plates, the diagonal sequence should be followed to ensure that the deviation of the upper and lower and left and right distances of the two clamping plates is no more than 8.0 mm. When clamped to the given tightening size, the deviation must be less than 2.0 mm. After tightening, the corner bolts can be tightened.
(9) Water pressure test: After equipment maintenance, a water pressure test should be performed. No external leakage or internal leakage indicates qualification. The steps are as follows:
a) Check whether the clamping size meets the sample requirements.
b) Install the blind plate and pressure test pump, and install the pressure gauge at the pressure test pump port.
c) Use an appropriate medium (generally softened water with a chloride ion content of less than 5%) for pressure testing.
d) Completely exhaust the air from the equipment and perform single-side pressure testing at 1.25 times the design pressure and hold the pressure.
(10) Leakage causes
a) Internal leakage of the medium: The cause is that the plate is corroded and perforated or the seal is aged.
b) External leakage of the medium: The cause is aging or improper assembly of the sealing gasket.
2. Chemical Cleaning
Chemical cleaning can be performed without disassembling the plates. First, close the system inlet and outlet valves, connect a cleaning system to the heat exchanger pipe, and circulate the corresponding cleaning medium in each side flow path. After the fouling is fully softened and detached, open the drain port to drain it, and then rinse it with clean water.
Note: The selected cleaning solution should not damage the plate material and sealing gasket.

VI. Maintenance
1. Heat exchangers that have stopped operating for the season should have the medium inside the equipment drained promptly, or other antifreeze measures should be taken to prevent the equipment from freezing.
2. If the equipment is not used for a long time, the clamping bolts should be loosened to a size of no less than 1.15L. When using, tighten according to requirements.
3. During normal operation of the equipment, if medium is found leaking from the signal hole, analysis should be carried out. If the bolts are loose or have elongated due to long-term heat exchange, they should be re-tightened as required, but not too tight to avoid damaging the plates. If the sealing gasket is aging, it should be replaced.