Thermal Oil Circulation Pump Selection Guide

How a Thermal Oil System Works

In a liquid-phase thermal oil system, the heater raises the heat-transfer fluid (HTF) to working temperature, and the circulation pump drives it through the heater and out to the process users — reactors, presses, dryers, calenders or tanks — before returning it to the heater. Because the HTF can operate at high temperature at low pressure, hot-oil systems avoid the capital and safety cost of high-pressure steam.

The pump is the heart of the loop: it must deliver the design flow at the pressure needed to overcome heater, pipe and equipment losses, while surviving continuous service at fluid temperatures that would destroy a standard water pump seal.

RY Series Key Specifications

Not suitable for water, chemicals or abrasive media. Confirm the final model, materials and performance against the actual system conditions before procurement.

Selection Checklist

1. Duty flow and head

Size the pump from the system heat load and the HTF properties at operating temperature. Calculate the total dynamic head from the heater, piping, valves and process equipment — never select from catalogue maximums alone. The published RY model range spans small units around 1 m³/h up to large circulation pumps of several hundred m³/h, with heads typically from about 20 m to over 120 m.

2. Temperature class and materials

Confirm the maximum fluid temperature, because it drives the casing material, the seal arrangement and the coupling design. The RY series is engineered for -20°C to 350°C service, covering most liquid-phase HTF systems in chemical, textile, food, petroleum and pharmaceutical plants.

3. Cooling and sealing

The RY design cools the bearing and seal housing with natural air-cooling fins, so no cooling-water piping is required — an advantage where cooling water is unavailable, expensive or undesirable. A combination of packing seal and mechanical seal with a heat-resistant auxiliary seal gives low-leakage operation, and an oil guide tube allows real-time observation of seal condition and HTF recovery status.

4. NPSH and suction conditions

Thermal oil systems normally operate with positive suction head from an elevated expansion tank or deaerator. Confirm the available NPSH at the highest fluid temperature, because the vapour pressure of the HTF rises steeply with temperature and can cause cavitation if the suction head is marginal.

Representative RY Model Data

Model numbers indicate approximate nozzle sizes and impeller diameter class. Exact duty point, efficiency and motor selection depend on fluid properties and system layout — verify against the performance curve for the chosen model.

Frequently Asked Questions