Refrigerated and Heating Circulating Bath

What is the Refrigerated and Heating Circulating Bath?

A refrigerated and heating circulating bath covers a wide range from about minus 20 to 150 degrees Celsius for reactor jackets, chromatography and material testing. It combines a compressor or thermoelectric cooler with a heater and pump.

Overview

This bath combines heating and refrigeration in one unit, giving a temperature range of about minus 20 to 150 degrees Celsius, and lower with a two-stage or low-temperature design. A compressor or thermoelectric module provides cooling, a sheathed or immersion heater provides heating, and a circulation pump distributes fluid to the external loop. Stability is typically plus or minus 0.1 to 0.5 degrees across the range, and cooling capacity is quoted at specific temperatures. Programs can ramp temperature over time for kinetic studies, crystallization and material testing. Safety features include over-temperature and low-level cutouts, compressor protection and alarm contacts. Bath volumes of 10 to 30 liters suit jacketed reactors and large instruments, and insulated connectors carry fluid to the application.

How does it work?

A circulation pump uses a centrifugal or gear impeller to push fluid through a closed loop at a controlled flow rate. The fluid passes through a heated or refrigerated reservoir, then to the application's jacket or heat exchanger, and returns to the reservoir. A temperature sensor measures the bath or the return line, and a PID controller adjusts the heater or refrigeration compressor to hold the setpoint. Pump pressure must be enough to overcome the resistance of the loop, tubing and the application, and flow determines how quickly heat is transferred. Key components are the reservoir, heater, compressor or thermoelectric module, circulation pump, temperature sensor and controller. Cooling capacity and temperature range define the envelope; pump pressure and flow define the loop performance. Some units also offer external temperature control with a probe at the application.

What are the key features?

• Range of about −20 to 150 °C in one unit
• Compressor or thermoelectric cooling with heater
• Stability of ± 0.1–0.5 °C across the range
• Temperature ramp programs for kinetic studies
• Over-temperature, low-level and compressor protection
• Bath volumes of 10–30 L for larger loads

What are the technical specifications?

A typical refrigerated and heating circulating bath configuration offers temperature range of −20 to 150 °C, temperature stability of ± 0.1–0.5 °C, heating capacity of 1–3 kW, cooling capacity of 300 W–2 kW at 20 °C, flow rate of 10–30 L/min and bath volume of 10–30 L. Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The Refrigerated and Heating Circulating Bath is used in reactor temperature ramping, chromatography column temperature control, crystallization and solubility studies, material and battery testing and viscometry across a temperature range. Across the wider Circulation Pumps class, laboratories also deploy it for reactor jacket temperature control, spectrometer and detector cooling and laser and optics thermal management.

Which standards and certifications apply?

Relevant standards and methods include IEC 61010-1, IEC 61010-2-010, IEC 61326-1, ISO 9001 and GB 4793.1. Certification candidates for this model are CE, RoHS and ISO 9001 manufacturing; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Use only the recommended fluid and change it periodically, because algae, scale and contaminants reduce heat transfer and can block the loop. Keep the reservoir above the minimum level to avoid pump cavitation and heater damage. Insulate external lines to reduce condensation and heat loss, and use the shortest practical tubing with few restrictions. Vent the loop to release trapped air before setting the controller, because air pockets cause temperature oscillation. Place the unit where ambient heat and dust are low, and clean the condenser or air filter on schedule. Follow IEC 61010-1 for electrical safety and check the pressure rating of the application loop before running at high pump pressure. Record setpoint, fluid and calibration data for traceability.

How do I select the right Refrigerated and Heating Circulating Bath?

Choose a combined refrigerated and heating bath when the method spans temperatures both below and above ambient, or requires ramps. For a fixed warm setpoint a heating bath is enough. In the RFQ, state the full temperature range, capacity at the critical temperatures, ramp rate and fluid.

How does it compare with other Circulation Pumps variants?

Begin with the temperature range and the cooling or heating capacity required at your working temperature, not at the lowest rating. Then check pump flow and pressure, because a high-capacity bath with a weak pump may not circulate adequately through a restrictive jacket or long tubing run. Choose the reservoir volume for the thermal mass and stability you need, and decide between internal control at the bath and external control at the application. Match wetted materials to the fluid; water is standard, but glycol mixtures extend the low-temperature range, and some applications need silicone oil. Consider noise, footprint, drain and fill access, and whether a pressure or flow indicator is included. For unattended operation, look for low-level protection, over-temperature cutout and remote alarm contacts.