Introduction: A shell and tube oil cooler fits an HPU when its flow group, ports, and mounting orientation match the unit you are designing.
Sizing starts with numbers the power unit already produces: pump flow, duty cycle, reservoir volume, and available frame space. The goal is to turn those into an initial DC series model group that connects to your piping, holds oil temperature where the system needs it, and installs without a layout redesign. The DC series covers 100 L/min to 600 L/min across five groups. Start with flow and heat load, then check ports, footprint, and orientation. Confirm the final match with the factory before you lock in a model.
Heat load is the amount of heat the power unit adds to the oil during continuous running. It includes pump and motor losses, relief valve losses, pressure drops across valves and cylinders, and heat picked up from a hot machine frame or warm factory floor. If the reservoir settles at a steady temperature above target, the cooler must remove that heat continuously, including on peak days. Oil flow sets how much fluid passes through the cooler each minute and how long it stays in contact with the cooling surface. The DC series is grouped by design flow: DC-300 at 100 L/min, DC-400 at 200 L/min, DC-500 at 300 L/min, DC-600 at 400 L/min, and DC-800 at 600 L/min. A cooler circuit moving roughly 280 L/min belongs in the DC-500 group, not the DC-300. A smaller group can starve heat rejection and leave oil temperature difficult to control in summer. A larger group adds shell diameter, length, and cooling water demand. Pick the group whose design flow sits at or just above the flow that actually passes through the cooler. Inside a DC cooler, oil travels along the shell side around a finned multi-tube core, and spiral guide plates keep it turning through the bundle instead of short-pathing across it. That continuous spiral movement holds oil velocity along the tube surfaces, which supports the oil-side heat transfer coefficient and reduces the dead zones common in a plain baffle layout. Cooling water runs through the tubes. For surface-combination estimates, use published heat transfer coefficient data such as the Engineering Toolbox table. Tube material is available in copper or copper-nickel, so the core can be matched to the water supply.
Port size determines whether a good flow match becomes a clean installation or a stack of adapters. DC series oil and water connections run from 3/4 in on the small end to 2 1/2 in on the largest group. Each group has its own pair: DC-300 uses 1 in and 3/4 in; DC-400 uses 1 1/4 in and 3/4 in; DC-500 uses 1 1/2 in and 1 in; DC-600 uses 2 in and 1 1/2 in; and DC-800 uses 2 1/2 in and 1 1/2 in. Undersized ports raise line velocity, which adds pressure drop, noise, and heat back into the system. Oversized ports on a compact cooler create reducers and consume the tight layout you wanted. Pumps. org standards provide background for power unit piping velocity and port selection. Footprint decides the final choice more often than thermal numbers do. DC series exterior diameters run from 89 mm to 219 mm, and total lengths run from 319 mm to 1785 mm. Diameter is rarely the problem on a skid; length usually is. The longest shells approach 1.8 m, so measure the real space along the axis you plan to use, including clearance for the connections and for pulling the tube bundle during maintenance. A short, larger-diameter cooler and a long, smaller-diameter cooler can serve the same duty. Your frame drawing determines which one is realistic. Mounting orientation is part of the same layout decision. Both horizontal and vertical mounting are supported across the range. Horizontal mounting generally drains more completely and gives easier access to the tube bundle, which matters when water scale builds up over a season. Vertical mounting saves floor area on a narrow or crowded skid, but it needs venting at the high point and draining at the low point so air can escape and water can drain from the shell. Settle the orientation before you finish pipe routing, because it shifts where the oil and water connections sit and how a technician reaches them.
Four pieces of information do most of the work of narrowing the DC series, and each one pushes you toward a different model group. Collect them together before you request pricing, because they interact. Flow sets the group; heat load and water temperature determine whether that group can hold the target oil temperature.
An initial shell and tube oil cooler match comes down to four inputs: oil flow and heat load, oil and water temperatures, port size and thread standard, and mounting orientation with real measurements from your frame. Those four narrow the DC series to a model group, a length, and a connection size you can draw into the layout today. Treat the first pass as an initial selection; a factory review confirms the final configuration against your site water conditions, heat load, and piping. Send your flow, target oil temperature, cooling water data, port standard, and available space to our engineering team for a model recommendation and a factory-direct quotation. Ask about tube material options, packing, and current lead time at the same time. For a skid with unusual space or connections, the same details support a custom oil cooler request.
A：Use the flow that actually passes through the cooler circuit rather than total pump displacement, since any bypass or separate return line changes the number. The DC series is grouped at 100, 200, 300, 400, and 600 L/min design flow across DC-300 to DC-800. Pick the group at or just above your circulating flow, then let heat load and water temperature settle the tube length inside that group.
A：Orientation changes the footprint on the skid, the vent and drain points, and how easily a technician can service the tube bundle. Horizontal mounting usually drains more fully and gives better bundle access. Vertical mounting saves floor area on narrow skids but needs venting at the top and draining at the bottom. Both are supported across the DC range, so choose before finalizing pipe routing.
A：Send oil flow through the cooler, estimated heat load, target and actual oil temperature, cooling water temperature and available flow, port size with thread standard, mounting orientation, available space, and tube material preference. With those details, a manufacturer can match a model group, confirm the configuration, and return price alongside packing and lead time. If any of those numbers are still estimates, say so, and the factory can guide the next step.
Heat Transfer Coefficients in Heat Exchanger Surface Combinations
Thermophysical Properties of Fluid Systems
