If you are looking for an ultimate space and money saver flow control, a triple duty valve is the best option. TDV is a combination of multiple valves: calibrated balance valve, spring loaded check valve, and isolated or shut-off valve. Combining the functions of those three makes this valve very appealing as you don’t have to purchase different valves separately. Its convertible body design enables on-site change in configuration, from straight to elbow style. A triple duty valve is great in single, double, and vertical pump applications and provides a quiet system operation. It’s available in a wide range of sizes and connections and features a memory button to allow the operator to return the valve to its set position after shutdown.
The working principle of a triple duty valve is very simple. Here is how it operates:
- Open position - when in this position, the clapper functions as an efficient check valve, and is hinged at an angle with 90% less dead weight to lessen slam and chatter.
- Balancing - this is done with a plug that holds the clapper at selected flow requirement.
- Closed position - it is the downstream part that closes first when the plug is being spinned towards the close position. This is to equalize the pressure so that the clapper closes with low resistance.
- Positive seal closure - it is achieved by the plug clamming against the clapper’s back.
When it comes to installation, the triple duty valve must not be mounted directly to the pump. This is to prevent system noise and damage to the check valve components, especially the clapper. Placing it directly on the pump discharge places it to a point of extreme flow and pressure changes and of high turbulence. When installed near the pump, it should be placed at a spool piece of 12” minimum on pumps with discharge size of 1.5” to 6”; while a 24” minimum spool piece is used for discharge sizes of 8”-12”. And as a balance device to measure differential pressure, an optimum operation can be achieved with a recommended distance of 10 times pipe diameters straight pipe be mounted upstream and 5 times downstream of the TDV. To ensure proper function, the triple duty valve must be closed at least 10%.
Islip Flow Controls, as the industry’s leader in manufacturing pipeline strainers and valves, offers products that are tested with applicable ASME and CSA standards. Our triple duty valves provide an automatic and silent operation and are spring loaded to make sure that it closes as the line flow becomes zero and to prevent water hammer. They are also supplied with handwheel for easy operation. We continue to create triple duty valve design features that will provide high efficiency and best results.