Three Ways to Avoid a Noisy Cavitating Pressure Reducing Valve

Want to avoid angry calls from customers complaining about squealing noises from pressure reducing valves? Take note of these 3 important steps when selecting a PRV:

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-?????? Correct Pressure Reduction Ratio

Attempting to reduce the supply pressure too significantly will result in cavitation of the reducing valve. RBM recommends avoiding that the ratio between

the upstream maximum pressure and the downstream adjustment pressure of the reducer exceeds the value of 2.5.

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i.e. Incoming pressure of 1,250 kPa should not be reduced to below 500 kPa.

A potential solution to high incoming pressure is to use multiple PRVs installed in parallel.

i.e. Incoming pressure of 1,600 kPa reduced down to 800 kPa.? Then a second PRV to reduce 800 kPa down to the requested 500 kPa.

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-?????? Flow Velocity

It is important to size the PRV accurately with your expected flow rate to prevent not only cavitation noise but potential excessive wear on the valve.

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It is advisable, therefore, to choose the diameter of the pressure reducer so that the speed of the fluid going through it, is contained within the following values:

Velocity = 0.7 to 1.5 m/s (residential use)

Velocity = 1 to 3.5 m/s (commercial or industrial use)

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-?????? Understanding Varying Operating Conditions

System requirements vary greatly during different hours of the day, or during different stages of a commercial project (i.e. low occupancy at the beginning of construction). This will present significant challenges to the PRV as the actual flow rate requirement may be significantly lower than the planned design flow.

A solution to combat this is to install a smaller PRV in a bypass arrangement. The smaller bypass PRV is typically set to approximately 50kPa higher than the main duty PRV and sized based on the minimum flow requirements of the system.

By taking these three critical factors into consideration during your design process, you will ensure safe and stable reducing valve operation free of noisy cavitation problems. Saving you time, money and guaranteeing satisfied customers.

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For more information please visit https://www.rbmsystems.com.au/pressure-reducing-valves or reach out to one of the team today.

[email protected]

rbmsystems.com.au

+61 7 3073 2428