What is an altitude valve for water storage tank?

Altitude Valve For Water Storage Tank

Altitude valves are hydraulically operated, pilot controlled control devices designed to regulate the water level in a water storage tank. They eliminate the need for floats or similar equipment and remain fully open until a preset shut-off point is reached.

Various types of altitude valves are available to meet specific applications and system requirements. Some are also equipped with auxiliary controls for multiple functions, such as pressure sustaining or reduction, solenoid override and rate of flow control.

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What is an Altitude Valve?

Altitude valves are used to control the level of water in a storage tank. They are used to compensate for varying water demands, as well as during firefighting or power outages. They are also used to prevent overflow using Pressure relief valve.

Altitude valves operate on a differential pressure between the inlet of the valve and the tank-level head pressure. When the inlet pressure is greater than the tank-level head pressure, the valve will assume a level of water in the tank and then close when it reaches the maximum set point.

In a situation where there is no difference in the inlet and tank-level head pressure, the altitude valve will essentially sit, floating open. It will attempt to fill the tank but won’t reach its maximum level setpoint because the system doesn’t have a sufficient inlet pressure to allow the altitude valve to fill the tank.

This can lead to the tank overflowing or damage. It can also cause the quality of the water to deteriorate.

There are two main types of altitude valves: modulating and single acting. Modulating altitude valves use a high sensitivity pilot to control the flow of the liquid in the tank.

When the water level reaches its top closing level, the pilot regulates the opening and closing of the main valve to maintain the water level. If the level drops slightly, it will slowly open and then slowly close again to regain any loss of the water level.

The three-way pilot regulator in a modulating altitude valve will trigger the valve to open and close by sensing the level of water in the tank. The difference between the opening and closing will be pre-set in the pilot to about one metre.

Depending on the application, additional functions can be added to modulating altitude valves. These include solenoid override, pressure sustaining or reduction, rate of flow control and more.

In addition, the altitude valve can be configured for bi-directional flow, so that it can control both the inlet and outlet to the tank. This can be done in a slightly modified design, or as an add-on feature to a standard altitude valve.

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Types of Altitude Valve

Altitude valves are used in a variety of water storage tanks with Flow Control Valve, including atmospheric and pressurized storage. They are commonly used in residential, commercial, and industrial applications to provide faster access to water.

They come in a wide range of sizes and can be made of different materials, such as aluminum, stainless steel, and polypropylene. They can also be designed with decorative elements to help blend them into the surrounding environment.

A standard altitude valve controls the water level in a water tank by opening and closing on a rising or falling liquid level. It requires no external power source and operates automatically, hence the name.

Typically, an altitude valve is installed in the supply line to the tank and is equipped with separate adjustable opening and closing speed controls. Variations include one-way flow with delayed opening, one-way flow with pressure sustaining, and two-way flow designs.

The 106 and 206 series altitude valves are controlled by a diaphragm-actuated three way spring-loaded adjustable altitude pilot (1), which senses the hydrostatic head pressure (pressure created by the weight of the water column). When the hydrostatic head equals the spring force, the pilot connects port "X" to "K"; when the hydrostatic pressure drops slightly, it connects port "K" to "EX". This reduces the hydrostatic head until the water level is at a preset maximum.

When the pressure head is below this set-point, the altitude pilot controls the action of the main valve by shifting the internal distributor in position (S - C) or auxiliary valve (8); this forces the chamber of the main valve to open. The opening speed can be adjusted on the tuning unit TUP - 93(rep7), from 1 to 6; never leave it on 0 or the valve will not open.

Another type of altitude valve is a modulating valve, which is similar in design to the regular altitude valve. Instead of purely opening and closing like the three-way altitude valve, a modulating valve uses a high sensitivity 2-way altitude pilot to modulate the main valve.

As the water level in the tank drops, the pilot opens slowly to 'top up' the level. Once the water level reaches a predetermined maximum, the pilot closes, and the control valve returns to a closed position. This allows for a smooth transition from opening to closing and back again without the risk of surges.

Altitude Valve Applications

An altitude valve is an automatic control valve that controls the water level in a tank or elevated storage reservoir. They vary in function depending on the system requirement. They can be configured for one-way or two-way flow service and are furnished with auxiliary controls for multiple functions, such as pressure sustaining, pressure reduction, solenoid override, and rate of flow control.

They are usually designed for high pressure or head applications and can be installed at water treatment plants, reservoirs, pump stations, or other places where water is stored and used. They are a popular choice for water supply systems that have a limited amount of space available to house large tank and reservoir control equipment.

Another common application for an altitude valve is to provide water level control at a tower or reservoir that is higher than the main supply line. The valve opens upon a preset low water level to refill the tank and closes when the tank reaches a higher water level.

For example, the City of San Francisco uses an altitude valve for its 200,000-gallon Relief Hill Road Storage Tank with Resilient seated gate valve (the only major storage component in the city’s treated water system). It is designed to close at a predetermined maximum level and open to refill the tank when the water level drops to a fixed distance below the high water level.

The main benefit of using an altitude valve is that it provides a safe way to control the level of the tank. It also ensures that the tank does not overflow if the incoming supply pressure decreases or the demand on the distribution system changes.

However, it is important to remember that the valve is only an effective way to control the water level when the incoming pressure or head stays at a steady, constant level. When the incoming supply pressure or head drops, an altitude valve can be difficult to operate effectively and may not react appropriately to the changing situation.

A more effective solution is to use an electronic sensor level controller. This type of device offers a number of benefits, including remote access, maintenance and operation reports, and improved monitoring and traceability of the system’s operation. These systems are now replacing the older, more complex float and pilot controlled valves.

Altitude Valve Maintenance

Altitude valves are a type of level control valve that is used in water storage tanks. They have different functions depending on their application, but they are generally hydraulically operated and pilot controlled.

These valves work by sensing a static level in a tank, then opening and closing the valve to fill it. They are typically installed in a high-level tower or water tank that requires automatic filling.

They can be configured with additional features like a float or stepped surge-preventing closure. This allows them to control incoming pressure as well.

This is important as it can help to prevent overfilling of the tank, which can lead to spillage and odor problems in the distribution system. It can also allow for the use of a separate valve to fill the tank when it is low.

It is important to service these valves regularly so that they are always working properly. This includes cleaning the valve and strainer, as well as dismantling the valve to check for any problems that may be causing it to malfunction.

There are two main types of altitude valves: the wye-pattern and the globe-style. The wye-pattern type of altitude valve has an inline design that allows for a more efficient flow rate and lower friction loss.

In addition to the wye-pattern design, there are other styles of altitude valves as well. Some are designed to be a double chamber valve that provides a non-return function.

This can be helpful for applications that have a variable with Wafer butterfly valve water usage demand and need to maintain a certain set tank level. This can be accomplished through adjusting the hydraulic control pilot or increasing the system inlet pressure.

If this is not possible, a differential head valve can be added to the altitude water control system. This is an auxiliary device that allows the altitude water control system to adjust the tank level without the need for manual adjustment of the hydraulic control pilot.

This can be a good solution for many applications, including water storage tank filling and draining. However, the process of setting up and adjusting this valve is often time-consuming and can be difficult to do in remote areas that have limited access to the valve.