A half screw is a type of installation connector, made of a loose nut, sleeve and often also a seal. It is used in water, gas and heating installations in buildings. In cold and hot water systems and central heating, a brass half screw is standardly used. It allows for the installation of a water or heat meter. Half screws made of stainless steel, polypropylene and PVC are also available. Learn about the types of half screws used in water installations, the mechanism of operation of the connector and its most important applications.
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Types of half-screws in hydraulics
Hydraulic installations (water and sewage, gas, central heating) are subject to regular maintenance work. Therefore, they should not only be easily accessible, but also dismantled/separable in selected areas, allowing for trouble-free dismantling of elements that may require replacement or repair. Thanks to this, it was not necessary to dismantle a large section of the pipeline. The need to disconnect installation elements often occurs at the points of connection of valves, sight glasses, flow meters, filters or pumps. Such parts are usually equipped with disconnect connections made using screw connections and half-screw connections.
A half screw is a type of disconnecting coupling. It consists of a nut with a pipe thread and a sleeve. It can be connected to any element of the pipeline. The solidity of the coupling and its proper size are very important for the tightness of the obtained connection. A half screw can be made of metal (brass, steel, cast iron) or plastic (polypropylene, PVC material).
Screw connections are also used to create screw connections in irrigation systems. A screw connection is a complete connector that consists of three threaded parts. It has threads on both sides. It can be in a reduced version (reducing screw connection) or with a change of direction (angular screw connection).
How does a half screw work?
There are many types of screw connections on the market, differing in their purpose and operating principle. Firstly, screw connections provide effective and tight connections in the pipe infrastructure - in places requiring periodic inspection, maintenance or replacement of components. Screw connections are detachable. They allow for easy disconnection of pipes and their rotation relative to each other, because the contact surfaces of the elements are pressed together using a nut (frontal clamping). The sleeve in the half screw connection ensures adjustment to all fittings of the same diameter. The nut allows for the creation of a threaded connection with another receiver.
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Application of half-screws
Thanks to screw connections and half-screw connections, it is easy to dismantle hydraulic system elements in order to perform service work. Ensuring detachability is the most important distinguishing feature of this type of hydraulic connection! The use of screw connections and half-screw connections definitely simplifies and speeds up the process of assembly and disassembly of pipe infrastructure elements. It also allows to reduce the number of connections, which significantly affects the efficiency of work and the service life of the entire installation. A typical example of the use of screw connections is the assembly of a radiator (a special radiator half-screw is used for this purpose), pumps and valves in the central heating system.
Screws and half-screws are also used when replacing damaged sections of the piping system, when it was not possible to unscrew the pipe, so it was cut or accidentally damaged, e.g. drilling during construction work. The use of these installation connectors allows you to connect a new part to the existing system, and thus avoid dismantling a large section of the pipeline.
Screws and half-screws are also used to attach hydraulic devices that are subject to cyclical inspections and maintenance (e.g. pumps), may require replacement (e.g. valves) or are dismantled for legal verification (e.g. meters). To facilitate service work, these devices often have factory-built screw connections.
A special type of connector - a half-screw reducing connector, allows for a reduction in the thread size of the connected element. In the case of central heating installations, when the thread on the pipes is smaller than the connecting thread of the heating device, the screw connector will allow its installation in the system, ensuring a reduction in diameter.
Half-screws at the Onninen wholesaler
At the Onninen plumbing wholesaler you will find straight and angle half-screws made of brass, stainless steel, cast iron and modern plastics. All fittings have been carefully selected to ensure ease of assembly, wide compatibility and uncompromising resistance and tightness of connections. We offer half-screws with various thread sizes, including:
Don't know which half screw to choose? Contact us! We will help you match the connectors to your specific installation.