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MDP Hydraulics
The hydraulic radiator tubular oil cooler, often referred to as a shell-and-tube oil cooler, is a highly efficient liquid-liquid heat exchange device widely used in industrial hydraulic systems. Its core design is based on the classic shell-and-tube heat exchange principle: cooling water flows inside the tubes, while the high-temperature hydraulic oil flows around the tube bundle outside the shell. The two materials exchange heat through the metal tube wall without direct contact. This product, with its sturdy structure, high pressure-bearing capacity, good reliability, and convenient maintenance, has become the preferred solution for medium and large hydraulic stations, injection molding machines, die-casting machines, ship deck machinery, etc., which require stable and continuous cooling. It is particularly suitable for fixed industrial sites with stable and clean cooling water sources.
Tube bundle: Multiple heat-conducting metal tubes (typically copper tubes, stainless steel tubes, or copper-nickel alloy tubes) are fixed in a certain arrangement (such as triangular or square) on the tube plates at both ends to form the core of the heat exchanger.
Shell: A cylindrical pressure vessel that encloses the tube bundles. The shell is equipped with an inlet and outlet for hydraulic oil.
End cap / water chamber: Located at the ends of the shell, it guides the cooling water into the tube bundle. It is usually divided into a fixed end cap and a floating end cap. The latter can compensate for the thermal expansion of the tube bundle and the shell due to temperature differences.
Baffle plate: Installed inside the housing, it guides the hydraulic oil to flow laterally or in a spiral pattern across the tube bundle, increasing the turbulence of the oil and disrupting the boundary layer, thereby significantly enhancing the heat exchange efficiency.
Cooling water path: The cooling water flows from the inlet of the water chamber at one end, travels in a straight line within the pipes (or undergoes multiple turns depending on the design of the number of circuits), absorbs heat, and then flows out from the outlet of the water chamber at the other end.
◦ Hydraulic oil path: Hot hydraulic oil enters the housing through the inlet and, guided by the baffle plates, repeatedly sweeps laterally across the outer surface of the tube bundle. The heat of the oil is transferred through the tube wall to the cooling water flowing inside the tube, and after being cooled itself, it flows out from the outlet on the housing and returns to the hydraulic system.
The baffles are designed to force the oil to flow in a turbulent manner, significantly increasing the heat transfer coefficient on the oil side outside the tubes.
The pipe wall is thin, with a high thermal conductivity and low thermal resistance, resulting in high heat transfer efficiency.
The design is mature, and the performance parameters can be accurately calculated. The cooling effect is stable and predictable.
The shell and tube sheet are both of heavy-duty construction, capable of withstanding the high working pressure of the hydraulic system (typically up to 1.6 MPa, 2.5 MPa or higher) and pressure shock.
Suitable for oil return cooling in high-pressure closed hydraulic systems or for independent circulation cooling circuits.
Removable tube bundle design: By loosening the end cover bolts, the entire tube bundle can be withdrawn from the shell, facilitating mechanical brushing or chemical cleaning of the water-side tube pass, effectively removing deposits such as scale and biological sludge. This is a significant advantage of this design compared to plate-type coolers.
The oil side housing has a large space, low flow resistance, and is not prone to clogging.
No moving parts, with very few failure points.
Select corrosion-resistant materials (such as naval copper, 304/316 stainless steel), which can adapt to various water qualities and oil types, and have a long service life.
Number of processes selectable: It can be set as single journey, double journey or multiple journeys to meet different requirements for water temperature rise and pressure drop.
Material options: Depending on the quality of the cooling water (fresh water, seawater, corrosive water) and the type of oil, different pipe materials and shell materials can be selected.
Interface customization: The oil port and water port offer various connection options such as flanges and threads, and the size can be customized according to the flow rate.
Product Outline Drawing:
Product Specifications:
Core Task: Calculate the required heat exchange area.
Input parameters: The known heat power of the hydraulic system (in KW), oil flow rate (in L/min), oil inlet temperature, desired oil outlet temperature, cooling water inlet temperature, available water flow rate, etc.
Method: Utilize professional thermal calculation formulas or software to calculate the logarithmic mean temperature difference (LMTD) and the total heat transfer coefficient (K value), and ultimately determine the heat exchange area. Usually, consultation with the supplier's engineer is required for the calculation.
Pressure: The design pressure on the oil side must be higher than the maximum working pressure of the hydraulic system (including shock pressure). The pressure on the water side must be higher than the pressure of the cooling water system.
Material: The type of pipe material is determined by the properties of the cooling water. For freshwater, copper alloys can be used; for seawater, geothermal water, or corrosive water, stainless steel or titanium pipes must be selected. The material of the shell is chosen based on environmental and cost considerations.
Fixed tube sheet type: Simple structure, low cost, suitable for situations where the temperature difference between the shell side (oil side) and the tube side (water side) is not significant (generally < 50°C).
Floating head type/U-shaped tube type: It can compensate for large thermal expansion and is suitable for working conditions with large temperature differences and high pressure. It is the more common choice.
• Industrial hydraulic systems: Large injection molding machines, die-casting machines, hydraulic machines, machine tool hydraulic stations.
Heavy Industry and Metallurgy: Hydraulic and lubrication systems for steel rolling machines, continuous casting machines, and forging equipment.
• Ship and Marine Engineering: Ship steering gear, deck cranes, propulsion system hydraulic systems (often cooled by seawater).
• Energy and Power: Wind turbine gearbox lubrication system, steam turbine speed control system.
• Chemical and process industries: Hydraulic cooling for equipment such as reaction vessels and extruders.
Ensure that the cooling unit's installation base is stable, and the inlet and outlet pipelines are properly supported to prevent stress from directly acting on the interface.
Oil port connection: It is recommended to install a stop valve near the oil port to facilitate isolation of the cooler during maintenance.
Water inlet connection: It is essential to install a filter (Y-type or basket type) on the water inlet pipe to prevent impurities from blocking the pipeline. It is recommended to install a pressure gauge and a thermometer for easy monitoring.
Flow direction: It is generally recommended that the oil flows from top to bottom and the cooling water flows from bottom to top (counter-flow arrangement) to achieve the best heat exchange effect.
Before starting, slowly open the cooling water valve to fill the tube section with water, and then open the exhaust valve at the high point of the water chamber to expel all the air.
Then allow the hydraulic oil to slowly fill the shell chamber, and also ensure that all air is expelled (this can be done through the exhaust port on the shell).
Regularly check the temperature difference between the inlet and outlet of oil and water. If the temperature difference significantly decreases, it may indicate a decline in heat exchange efficiency (such as scaling on the water side).
Monitor the pressure of oil and water. An abnormal increase in pressure drop may indicate blockage.
Water-side Cleaning: Based on the water quality, regularly (e.g., every six months or annually) remove the scale from the inner walls of the tubes by disassembling and cleaning. Use mechanical brushes, high-pressure water, or mild chemical cleaning agents.
Oil-side inspection: Check whether there is any oil sludge or carbon deposits on the inner wall of the casing and the outer wall of the tubes. If necessary, rinse with oil or cleaning agent.
Sealing replacement: During major maintenance, replace all the sealing gaskets of the end covers.
Winter freeze prevention: When the equipment is to be out of service for an extended period, the cooling water in the pipeline must be completely drained to prevent freezing and cracking.
