Cooling System Design for Heavy-Duty Drilling Equipment

Bar-and-Plate Oil Cooler + Replaceable Copper-Tube Radiator/CAC

A U.S. drilling OEM project showing why hydraulic oil, engine-coolant and charge-air circuits can require different heat-exchanger structures.

Complete cooling package delivered for the U.S. drilling OEM project

1. Project Background: One Machine, Different Cooling Requirements

This project involved a customized cooling package for heavy-duty underground drilling equipment supplied to a U.S. drilling OEM. The key engineering point was not to apply one core structure to every cooling circuit. The hydraulic oil circuit, engine-coolant circuit and charge-air circuit place different demands on pressure capability, heat transfer, packaging and maintenance.

SINRUI therefore used two different construction strategies within the same cooling package: a reinforced aluminum bar-and-plate oil cooler for the hydraulic circuit, and replaceable copper-tube construction for the main radiator and charge-air cooler (CAC).

2. Bar-and-Plate Oil Cooler for the Hydraulic Circuit

The hydraulic circuit required a compact oil cooler with a strong integrated structure. SINRUI specified an  aluminum bar-and-plate core manufactured by vacuum brazing, using aluminum separator plates and sealing bars to form a rigid assembly.

As part of project validation, the oil cooler was pressure-tested to 550 PSI. The purpose of this test was to verify structural and sealing performance under the specified hydraulic pressure requirement; it should not be interpreted as a universal industry standard or as a burst-pressure rating.

· Vacuum-brazed aluminum bar-and-plate construction for compact, integrated strength.

· Pressure-tested to 550 PSI for the project requirement.

· Designed to reduce the risk of leakage or core damage associated with hydraulic pressure fluctuations.

· Suitable for tight equipment layouts where packaging space is limited.

3. Replaceable Copper-Tube Radiator and CAC

For the main radiator and charge-air cooler, SINRUI used a replaceable-tube structure with 99.9% high-purity copper tubes. Copper provides high thermal conductivity together with useful ductility for a serviceable tube design.

The tubes are retained with flexible FKM (fluoroelastomer) seals rather than being permanently welded into one integrated core. This allows the assembly to accommodate vibration at the tube-to-header interface while also creating a practical maintenance path.

For underground drilling equipment, material selection should always follow the customer’s site requirements and applicable safety standards. Copper-based construction can be part of that material strategy where minimizing exposed aluminum is specified, but the cooling package itself should not be described as an intrinsically safe certified device unless the relevant certification applies.

Detail of the replaceable copper-tube radiator/CAC core

4. Field-Serviceable Cooling: Replace One Tube, Not the Entire Core

Serviceability was an important part of the design. If an individual cooling tube is damaged, technicians can replace the affected tube instead of automatically replacing the complete radiator core. For equipment working far from a specialist radiator workshop, this can be just as important as cooling capacity.

· Individual damaged tubes can be removed and replaced.

· FKM seals support sealing and vibration accommodation at the tube interface.

· Less of the cooling package needs to be removed from service for a localized tube issue.

· Maintenance teams gain more flexibility over repair timing and spare-parts planning.

Compared with conventional folded-core designs, where localized damage can require more extensive repair or module replacement, a replaceable-tube system provides a clearer field-maintenance path for certain failure scenarios.

Replaceable copper-tube core and protective frame detail

5. Four-Step Inspection Before Shipment

Each cooling system follows SINRUI’s radiator manufacturing and inspection process before shipment to verify sealing, pressure performance, finish quality and dimensional compatibility.

What This Project Shows

Heavy-duty drilling cooling should not be treated as a single-component selection. Different circuits can require different construction methods:

· High-pressure hydraulic oil circuit → aluminum bar-and-plate cooler.

· Engine-coolant and charge-air circuits → serviceable replaceable copper-tube construction.

The correct solution depends on the actual thermal duty, operating pressure, medium, installation envelope and maintenance strategy. Matching the core structure to each circuit can improve both cooling performance and long-term serviceability.