Spears PVC gate valves are, in our opinion, the best valve for fine control of flow rates.
The handle has to be turned many times between fully closed and fully open states which gives the ability to set very accurate flow rates.
The full bore design of the valve (when fully opened) also enables any blockages or fouling to be quickly cleared by opening the valve. This is not the case in many other designs of fine control valves, such as diaphragm valves, where the complex route of the water through the valve can block very easily, resulting in the valve then having to be taken out of service and dismantled to clear the blockage.
All wet parts in the Spears Gate Valves are plastic, which eliminates the risk of corrosion. The valve can be completely dismantled by unscrewing the cap beneath the handle and the whole mechanism removed. We would recommend that unions are installed either side of the valve to allow for quick valve removal for servicing should it be required.