FEATURES
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The float valve arm may vary from valve design to valve design and should not be shortened, as it will affect the fulcrum power needed to close the float valve.
• Pressure control valve The pressure control valve( PCV) is a type of valve used to control or limit the pressure in a system or which can build up for a process upset, instrument or equipment failure, or fire. The pressure is relieved by allowing the pressurised fluid to flow from an auxiliary passage out of the system.
The pressure-reducing valve( PRV) only has one function and that is to reduce incoming mains pressure to an acceptable working pressure. If the pressure builds up on the low-pressure side of the valve it cannot rid the system of this extra pressure. A separate pressure relief valve must be installed for this function. A PRV automatically releases a substance from a boiler, pressure vessel, or other system when pressure or temperature exceeds pre-set limits.
• Pressure safety valve A pressure safety valve( TP & S valve) is fitted to a pressure vessel as an extra safety measure to protect the system against over pressurising and overtemperature situations. The valve only opens during extreme situations and the discharge pipe is viewed as a dry pipe. This valve should ideally be replaced once it has discharged.
• Check valve A check valve is the valve that relies on media flow to automatically open and close the disc. It is used to prevent the media backflow, and is also known as a one-way valve or a reflux valve. There are two types of shut-off mechanisms: one is a flap type valve that should only be used on an ascending pipe line, and the more commonly used check valve that has a spring-loaded mechanism that does not require water flow to close the valve.
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Valve and Actuator Manufacturers Cluster of South Africa
The Valve and Actuator Manufacturers Cluster of South Africa( VAMCOSA) was formed in July 2011 and works within the dti’ s designated cluster parameters. VAMCOSA’ s focus is to bring local valve and actuator manufacturers together to create a common focus and goal for the respective industries. VAMCOSA provides an effective platform for its members to lobby government through designated channels of the dti and the SACEEC about industry specific concerns.
Goals
• Promote localisation One of the main goals of VAMCOSA is to grow the South African valve and actuator industry and encourage localisation, which will, in turn, improve job creation and skills development. VAMCOSA promotes the manufacture of products in South Africa with locally produced castings, forgings and materials, which will in turn create jobs through local procurement, increasing the value chain both upstream and downstream, and promote growth and sustainability. The VAMCOSA platform provides the opportunity to promote interaction between the local valve and actuator manufacturers and state-owned companies( SOCs) and municipalowned enterprises( MOEs). Through this effort, it becomes easier to define what the SOCs and MOEs require from local valve manufacturers, as well as to compare their requirements equally with the products offered by local and international manufacturers.
• Promote export of locally manufactured valves and actuators VAMCOSA, in conjunction with the SACEEC, will continually develop export marketing strategies that will provide the opportunity for the local valve and actuator manufacturers to present their products at appropriate international trade shows and encourage the development of relations with key export markets.
• Promote transformation Using this platform, VAMCOSA plans to promote transformation within the valve and actuator industry by jointly looking at enterprise development in valve-orientated businesses.
• Create a respected quality marque VAMCOSA aims to improve and maintain standards and specifications and create ones that are uniform throughout the SOCs and MOEs. VAMCOSA continually look for ways to improve our collective technology through research and development and work closely with the national foundry technology network and the local foundry industry to this end.
www. plumbingafrica. co. za May 2017 Volume 23 I Number 3