Cycling pressure bench for hot water tanks

THE SOLUTION PROVIDED BY LF TECHNOLOGIES

Our client is one of the world’s leading suppliers of heating and refrigeration systems. He contacted us to set up a test bench for his range of domestic hot water tanks.

Main functions

Objective

Design a hydraulic test bench for testing hot water tanks under cyclic and static pressure.

The cyclic pressure test is carried out in accordance with standard EN 12897.

PROBLEMATIC ISSUES

As the hot water tanks under test have very large volumes (up to 1000 litres) and some of the tests have to be carried out at regulated temperatures (up to 90°C), the bench had to be capable of generating both test pressures and a sufficient flow rate to ensure that the test temperature was uniform.

SOLUTION AND RESULT

The test bench is a pressure generator placed next to the products to be tested. The hydraulic bench can test up to 4 hot water tanks simultaneously.

The products are connected to the bench via a connection board. The programmable cycle purges the products. All connected products are subjected to the same test: identical pressure, flow rate and temperature.

A centrifugal pump generates a static pressure of up to 20 bar and can deliver a flow rate of 50 l/min at 12 bar.

Pressure test :

Hot water cylinders are subject to static pressure of up to 20 bar. The tests are carried out without water circulation. To prevent the water at the pump from overheating, an automatically controlled valve isolates the pump from the hot water tank, and the pump can stop.

If the test pressure drops, the pump injects water back into the tank.

Cyclic pressure test :

Unlike proof tests, cyclic pressure tests can be carried out at any temperature. It is therefore necessary to have a flow during the tests to ensure a good test temperature.

A manual control valve adjusts the circuit’s pressure drop, and the pump cycles pressure according to programmable profiles.