Loading Valves and Multi-Function Valves
When using a chemical dosing pump it may be advisable to use a loading valve or a multi-function valve.
A loading valve is a type of valve which is designed to provide a fixed back pressure for the dosing pump to work against.
Working against a fixed back pressure provides a number of advantages to many common dosing applications. For instance, when dosing into a pipeline, the pressure in the pipe can vary. To ensure that a dosing pump delivers a fixed volume of chemical reagent, the pressure must be stable because when the pipe pressure / back pressure varies, the corresponding volume of reagent delivered by the pump will also vary. So by fitting a loading valve and fixing the back pressure, we can ensure that each stroke of the dosing pump delivers the same displacement of chemical reagent. This is particularly crucial in chlorine dosing applications within water treatment processes.
Another benefit of using loading valves is that they prevent syphoning through the dosing pump. This is important when the physical setup of a dosing system can result in the syphoning effect.
Each of our multi-function valves includes a loading valve function. We also offer our 10400 range of adjustable loading valves, which result in very precise control of the back pressure that the pump is working against.
Multi-function valves are commonly called 4 function valves or 5 function valves - depending on the number of functions that the manufacturer can claim that they deliver.
Loading Valve / Anti-Syphon Valve
A multi-function valve also includes an adjustable loading valve or anti-syphon valve. This allows the back pressure to be manually adjusted to give the pump a constant pressure to work against.
With a constant pressure to work against, the amount of chemical reagent delivered by the dosing pump is fixed, allowing chemical processes to be tightly controlled.
The back pressure provided by the loading valve also acts as a non-return valve, thus preventing the chemical in the pipeline from returning back down the discharge tubing.
As the loading valve creates the back pressure for the dosing pump to work against, this prevents syphoning of chemical reagent through the pump and back into the pipeline.
Pressure Relief / Safety Valve
Each multi-function valve also acts as a safety valve or Pressure Relief valve. This is a safety feature, designed to prevent discharge pipework from operating outside the designated working pressure.
Should the discharge pipework become blocked (commonly caused by caustic freezing) a dosing pump could still be called to pump against the blocked tubing.
Should the pressure exceed the operating pressure of the dosing tubing - in the most serious instance this could result in injury or harm. As a preventative measure a pressure relief valve is placed between the discharge point of the pump and the discharge tubing. Should the pressure exceed a set amount, the valve opens relieving the pressure and diverting the chemical reagent back to origin.
The pressure that the safety valve operates is manually adjustable and should always be set lower than the maximum operating pressure of the discharge tubing.
The 10400 inline loading and anti-syphon valve is a fully adjustable anti-syphon and loading valve for use with a range of dosing pumps.
With an operating range of 0.5 - 10 Bar the 10400 is fully adjustable and designed to be mounted inline with a dosing pump.
The 10400 is manufactured in PVC with a choice of seal materials to provide compatibility with a wide range of chemical reagents and has connections for either 4 x 6mm or 8 x 12mm dosing tube.
The 11243-PVDF is a multi-function valve which is designed to be mounted on top of dosing pumps using the discharge point threaded connection.
Manufactured in PVDF with a choice of seal materials the multi-function valve provides connections for 4x6mm or 8x12mm dosing tube.
The 11243-PVDF multi-function valve offers a loading valve, anti-syphon valve and pressure relief functionality to chemical dosing processes.