Electricity and Control July 2022

MEASUREMENT + INSTRUMENTATION : PRODUCTS + SERVICES

Diaphragm valves for water level control

ment, the head of water charges the diaphragm. This causes the valve to close. Diaphragm valves can face up or down. This makes them very versatile. Other uses include: - Canal flow regulation for raw water in irrigation schemes - Discharges into holding or balancing dams in irri gation schemes: the diaphragm valve controls the inflow as well as closing when the dam is full - Flow control into raw water and wastewater treat ment works - Top and bottom inlets for reservoirs - Bottom outlets from dams (the diaphragm valve has good energy dissipation characteristics) - Actuation and control for automatic spillway scour and canal gates. Diaphragm valves need no maintenance, which makes them especially suitable for remote sites and the sometimes harsh African conditions. Flow can be controlled automatically, as described above, but diaphragm valves can also be fitted with a small electric actuator and connected by telemetry to al low for remote adjustment. For more information contact Ultra Control Valves. Email: peter@ultravalves.co.za Visit: https://www.ultravalves.co.za

Standard pilot-operated globe control valves are often specified for level control. But, they are not suitable in some installations: - In low pressure installations (below 1.5 bar dynam ic pressure) - When dirt particles in the water might clog small openings - Where they might be subject to vandalism. Peter Telle of Ultra Control Valves says in such cases, diaphragm valves offer several advantages. - They have a wide range of operating pressures: 0.5 bar to 6 bar inlet pressure is typical. The inclu sion of a ratio-reducing valve upstream allows for higher inlet pressure if needed. - They are available in sizes from 100 mm to 1 600 mm - They can be installed inside the reservoir, below water level, which reduces the risk of vandalism - They can be fabricated to suit reservoir piping con figurations; this reduces costs when retro-fitting to existing pipework - They are installed and commissioned by the fac tory team. The required level is set at the sensing element. This can be adjusted. When water enters the sensing ele