½" to 2" solenoid valves are often used to shut off or open a flow in water pipes. There is a minimum pressure in domestic water pipes so that the servo-controlled solenoid valves can be used here without any problems. However, if you want to control the flow of a tank, the solenoid valve only must deal with the hydrostatic pressure, which is often well below 0.3 bar. In this case, we recommend the servo- controlled valves, which also work without minimum pressure and are available up to 1".
Brass solenoid valves, which are designed for large flow rates, are used in many areas of industry, in building services, especially sanitary technology, and for irrigation. Our large warehouse offers you an extensive selection. The short delivery time is particularly favorable if you need the components immediately. In this category you will find 2/2-way solenoid valves made of brass or stainless steel. The designation of the way means that the valve has two pipe connections and that the two switching positions "open" and "closed" are possible. With solenoid valves, an electrical signal activates a solenoid, causing the valve to open or close. These valves can be controlled quickly. They are suitable for both liquid and gaseous media. Their task is to stop or release the flow of the medium. They are not suitable as safety valves. These solenoid valves are mainly made of brass, with stainless steel used for the armature guide systems and the valve seats. Brass and stainless steel are very resistant. Various materials are available for the seals. The appropriate sealing material depends on the area of application. For example, NBR is suitable for air, water and oils with a temperature between -10 and +90 °C. EPDM is mainly used for hot water and steam. It also withstands weak acids and bases with a temperature between -10 and +120 °C, but not fatty media. FKM withstands temperatures from -10 to +130 °C and is mainly used for hot water and hydrocarbons.
Switch position and connection sizes
You will see the additions NC or NO in the product descriptions and the filter function for the search. This will tell you if the valve is open or closed when there is no power. NC stands for "normally closed", which means it is normally closed. Normally open NO stands for "normally open". Energizing the solenoid with power causes NO valves to close and NC valves to open. In addition, there are valves that are bistable. There is no fixed rest position for these. They receive two different control signals and always remain in the last switched position. When choosing the valve, the connection size is also important. You can therefore use the filter function when searching for a product and display all valves with a specific thread size. This is a cylindrical Whitworth pipe thread for non-thread sealing connections according to ISO 228-1. The inches in the descriptions do not match the actual inside or outside diameter. This is because the inch measurement originally referred to the inside diameter. However, this became larger and larger over time due to the use of thinner materials, while the outer diameter was retained for reasons of compatibility. If in doubt, use the relevant tables to determine the correct connection thread. As a first orientation, you can see the diameter of the hole in millimeters next to the thread designation:
Flow factor and type of control for solenoid valves
The high flow factor is typical for the valves in this category. This is also known as the Kv value. It indicates the volume that the valve allows to flow through in one minute at a differential pressure of 1 bar and a temperature of 20 °C. The Kvs value is specified in the product descriptions. This is the Kv value of the fully open valve. Which valve is the right one for the respective application depends on various conditions. First of all, the type of control is important. In the category of large flow solenoid valves you will only find servo-operated and positive-operated valves. In other areas there are also directly controlled models in which the valve is opened or closed immediately by the activation of the electromagnet. In contrast, servo-controlled valves mainly use the differential pressure of the medium to open. The electromagnet has only a pilot function. Also known as indirectly controlled or pilot operated, these valves are suitable for applications where a relatively small magnetic force must control large flow rates and flow rates. They work a little slower than directly controlled valves and, in contrast to them, always require a certain minimum pressure. They are used, for example, in sanitary engineering and irrigation systems. Another type of control is forced control or semi-direct control. These valves operate at low pressure like the direct acting models because the armature is bonded to the sealing diaphragm. However, the valve cannot be fully opened in this way. If the pressure of the medium increases, it opens the valve further, possibly even completely. It is therefore a combination of direct control and servo control. Positively controlled valves do not require a minimum pressure in order to function. That´s why they are also suitable for areas of application for which directly controlled valves are normally used. In contrast to this, a relatively low magnetic force is sufficient even for large flow rates.
Tips for product selection and installation
In the product descriptions you will find information on the maximum flow factor as well as the minimum and maximum differential pressure. This is the difference in pressure between the inlet and outlet of the valve. The nominal width is also specified. This is the narrowest point inside the valve. You can also see the permissible ranges for the temperature of the medium and the ambient temperature here. Furthermore you can check which media the valves are suitable for. Brass as the valve body material is very resistant, even to aggressive media, but an important role plays the material of the seal. When configuring the product, there are also various suitable magnetic coils to choose from, namely coils for direct or alternating current and for different voltages. You can also buy a valve without a coil and easily assemble it yourself. When installing the valves, ensure that they are protected from moisture. Any condensation that may occur must be able to drain off completely. The electrical connection is made using device plugs, which you can also obtain from us. We are specialists in trading in valves and fluidic accessories. Our large warehouse enables a short delivery time, so you can buy the required components quickly and cheaply.