What are the types of valves in water treatment plants?
In a previous article, we mentioned several types of valves in water treatment plants. In this article, we list the remaining types and an overview of each type. To prepare a brief guide to the types of valves used in everything related to industrial, commercial, and domestic water applications.
The importance of different types of valves
Valves control the quantity, pressure, and flow of liquids and gases, as well as releasing and stopping their flow. Valves are designed according to their use and installation locations and are made of metals that suit the type of liquid and gases that pass inside them. The path and direction of the flow are determined according to the shape of the valve body, and the need may arise for the flow in one of the network pipes to be in only one direction.
Isolation valves can also be operated in several ways: manually, electrically, hydraulically, or by compressed air. The method of operation depends on the location and function of the valve and the power source available. Manual operation is the most common way to operate the valve.
Different types of valves in water applications
Gate Valve – Angle Valve – Ball Valve – Globe Valve – Wall Concealed Valve Butterfly Valve – Check Valve – Float Valve – Air Relief Valve – Pressure Reducing Valve (PRV) Strainer – Foot Valve – Pressure Relief Valve – Flush Valve – Thermostatic Mixing Valve
Gate Valve
It is also called the Sakina valve, and it is the most common type of valve in supplying water to buildings. It is used to open and close the main and secondary water lines, as well as at the inlets and outlets of pumps and tanks. This valve is used either to open or close water and is not used to control water quantities. It is characterized by a low value of water pressure loss through it.
Angle valve
In the angle valve, the direction of the water exit is perpendicular to the direction of entry, and it is usually installed on the outlets feeding several things, such as the sink (sink), the toilet base assembly, and the heater.
Ball Valve
A ball valve is a quarter-turn rotary valve that uses a spherical disc to stop or start the flow, knowing that most ball valves are of the quick-control type, as it requires a 90-degree rotation of the valve handle to operate the valve.
These valves have a ball with a hole in the middle connected to an outer handle. When the handle is parallel to the water supply pipe, the valve is open; When upright, the valve is closed and this handle acts as a visual aid so you know at a glance whether the water is on or off.
Globe Valve
It is usually used to control water inside the building. If it is buried inside the wall, the visible part of it is chrome plated for small diameters. It can also be used to calibrate the amount of water flow rate of pumps. In this type of valve, the percentage of pressure loss is higher compared to the valve gate valve.
Wall Concealed Valve buried inside the wall
It is a type of globe valve and is used in water networks buried in the wall at the main water entrance in bathrooms and kitchens. It is completely inside the wall, and the handle and nickel face appear on the ceramic surface, where the handle is chrome-plated or made of plastic out of consideration for the aesthetic aspect.
Butterfly Valve
A butterfly valve is a valve with a circular body in the middle of which there is a rotating disk and connected to a metal rod stem. Rotating the leg causes the disc to rotate. Several methods are used to rotate the stem. Valves with small diameters use a regular circular hand to open and close them, or a lever with a hand lever. As for larger diameters, actuators of various types are used, such as electric actuators, air pressure, or hydraulic oil. In the case of manual or automatic operators, a gearbox can be installed to facilitate the rotation of the disc
Non-Return Valve & Check Valve
Its function is to allow water to pass in one direction only and not to allow it to pass in the opposite direction. It is usually used with water pumps. If there is a water tank in the building, it does not allow water to return from the tank to the public network.
Spring check valve
There is a type that works with the idea of having a zipper that pushes a rubber stopper by the water, which compresses and opens the stopper and allows the water to pass through. If the water comes from the other direction, it pushes in the direction of the zipper opening, thus sealing it. Its body is made of copper and is commonly used.
Swing check valve
The second type of work is based on a cast iron blank in which a copper loaf is freely suspended. If water comes from a direction that pushes it and passes through it. If it comes from the other direction, it pushes it in the direction of closing the hole.
Float valve
The function of this valve is to control the filling of tanks with water, as the valve is installed at the top of the tank. When the water reaches this level, the valve closes automatically.
Air Relief Valves – air vent
The function of this valve is to expel air from the network without allowing water to escape with the expelled air. It is installed at the highest points in the network. That air is concentrated because its density is lower than water.
The theory of its operation is simple, as it is an empty, spherical container. It has an opening at the top and inside it is a rubber ball that is slightly smaller than the space of the ball. If there is air in the line, the rubber ball falls, the upper hole opens, and a shower of air comes out with some water. If the air runs out and the water level inside rises. The rubber ball floated on the water, rose, blocked the upper hole, and the situation stabilized.
Pressure-reducing valve P.R.V
It is used at the building’s water inlets to reduce the water pressure to a value suitable for use and in places where the pressure in the network is irregular. It is also used to supply some devices whose manufacturers recommend that the water pressure supplied to them not exceed a specific value. The valve has a maximum inlet water pressure within the pressure reduction range, which is adjustable.
The filter is installed before sensitive equipment and machinery to protect it from any solid objects entering it. It resembles the joint of the letter Y, but the diagonal branch has a flange covering it, which can be removed, and inside it is a cup-shaped strainer. From time to time, it must be dismantled and cleaned, and when installed, the diagonal branch must be at the bottom of the line. It indicates the direction of water flow so that solid objects are caught by gravity.
Foot Valve
It is used to maintain the liquid level in the suction line in centrifugal pumps and is equipped with a Strainer at the end to trap impurities so as not to cause loss or blockage in the pump suction. The function of the valve is a non-return function, and it is installed on the suction line in low places such as swales.
Pressure Relief Valve
A relief valve is a valve whose purpose is to absorb or discharge pressure over a certain limit so that it does not reach a point where it causes breakage or damage to pipes.
The valve has a spiral port into which a seal is installed. This plug is held somewhere by a lever that carries a weight. Many relief valves use a spring instead of a weight; This is because the spring is rarely damaged.
It is installed near pumping stations and installed at boiler inlets. Water heaters also use relief valves and are used in low places in water distribution networks within cities.
Bathroom Flush valve
It is a type of valve that operates by manual pressure and closes automatically after removing a sufficient amount of water to clean the toilet or urinal. The valve can be inside or outside the wall. This type is characterized by its low need for maintenance compared to expulsion boxes.
The flush valve requires a water pressure ranging from 1.5 to 2.5 bar to operate. This type of valve is commonly used in public bathrooms, such as mosque bathrooms, to rationalize water use.
Thermostatic Mixing Valve
Thermal mixing valves mix hot water with cold water while ensuring a constant and safe outlet temperature. They are used in residential, commercial, and institutional applications where water temperature control is critical to avoid thermal shock and bacterial growth in pipes.
