http://www.engineeringnews.co.za
  SEARCH
Login
R/€ = 13.14Change: -0.15
R/$ = 12.05Change: -0.20
Au 1200.03 $/ozChange: -6.12
Pt 1139.50 $/ozChange: -16.00
 
 
Note: Search is limited to the most recent 250 articles. Set date range to access earlier articles.
Where? With... When?








Start
 
End
 
 
And must exclude these words...
Close Main Search
Close Main Login
My Profile News Alerts Newsletters Logout Close Main Profile
 
Agriculture   Automotive   Chemicals   Competition Policy   Construction   Defence   Economy   Electricity   Energy   Environment   ICT   Metals   Mining   Science and Technology   Services   Trade   Transport & Logistics   Water  
What's On Press Office Tenders Suppliers Directory Research Jobs Announcements Letters Contact Us
 
 
 
RSS Feed
Article   Comments   Other News   Research   Magazine  
 
 
Nov 04, 2011

Stringent legislation drives demand for VCP pressure release valves

Back
Agriculture|Construction|Africa|Environment|Pipe|Safety|Welding|Africa|Equipment|Product|Steel|Environmental|Pipe|Valves
Agriculture|Construction|Africa|Environment|Pipe|Safety|Welding|Africa|Equipment|Steel|Environmental|Pipe|Valves
agriculture|construction|africa-company|environment|pipe-company|safety|welding|africa|equipment|product|steel|environmental|pipe|valves
© Reuse this



Multidisciplinary equipment supplier WAM South Africa says more stringent safety and environmental laws have led to companies conforming to the use of its over/under (VCP) pressure relief valve.
These new laws include the South African government’s imposition of European standards on the South African pressure equipment sector in October last year.

Further, the new pressure equipment regulations (PERs), promulgated under the Occupational Health and Safety Act, of 1993, previously referred to as the vessels-under-pressure regulations, came into effect in October 2009.

Competent persons qualified under the South African Institute of Welding and approved by the South African Qualification and Certification Commit- tee to pressure-test pressure vessels had until April 1 to conform with the new PERs.

“Since the laws on pressure silos have become a matter of safety for personnel and the environment, customers have been resorting to our VCP pressure relief valves,” WAM South Africa GM Emilie Marchand says.

Pressure Vessels

She explains that a silo becomes a pressure vessel when it is filled and subjected to overpressure. In such cases, the VCP valve will open and release excess pressure exceeding 1 bar to prevent the silo from exploding or being damaged.

However, when the silo is being discharged, underpressure can also occur. “In this case, the valve will open up and allow pressure from the environment to enter the silo to regulate the pressure,” Marchand adds.

The VCP valve consists of a cylindrical casing with a bottom flange that is connected to a spigot on the silo’s roof. A disc-shaped inner steel lid for nega- tive pressure operation is held in position by a central spring rod, while an outside steel ring for excess pressure is kept in position by three spring rods, gaskets and a weather-protection cover.

Marchand says helical springs keep the valve lids closed when the pressure value remains within the preset limits. The three spring rods on the outside of the valve keep the external ring-shaped lid firmly closed as long as the force generated by the pressure inside the silo does not exceed the spring force.

“Once the pressure exceeds the preset value, the lid is pushed up and the pressure can escape. The smaller lid covers the central circular opening of the external lid from below. It is held in the middle by a single spring rod and is pressed onto the external lid by the normal air pressure inside the silo,” she adds.

In the event of suction pressure, the spring is compressed and enables the lid to drop. The air entering the silo from outside ensures rapid pressure balance and pushes the central lid back up into the closed position.

However, Marchand says, spillage on construction and cement plants is problematic, owing to the lack of a regulating body to monitor the pressure with which tankers offload their product pneumatically into silos.

“Tankers often increase their off- load pressure to help [speed up] the process. “This results in major overpressurisation in the silos, which causes the VCP valves to constantly open and spillage to occur. “This is worrying, as these valves are only supposed to open in the event of an emergency,” she points out.

Regulation

It is difficult for plant managers to regu- late the tankers, which are owned and managed by third-party companies.

To deal with this challenge, WAM South Africa has offered its VHS membrane pressure relief valve as a solution.

The VHS is based on the same con- cept as the VCP valve; however, it has an outlet that enables it to be connected to a pipe. “If the valve does open, owing to overpressure, the spillage can be channelled back into the silo. This has various environmental benefits, especially with the spillage of fly ash or cement,” Marchand says.

WAM South Africa’s primary focus has historically been on batching plants; however, she states that the company is turning its attention to other sectors, including the agriculture, food and beverage and glass sectors.

Edited by: Chanel de Bruyn
© Reuse this Comment Guidelines (150 word limit)
 
 
 
 
 
 
 
 
Other Valves News
BROADENING INDUSTRY The Pumps, Valves & Pipes Africa Expo provides an ideal platform for suppliers to reach new and existing markets and explore business opportunities
Global forecasts of increased growth in the pumps, valves and pipes sector reflect market realities and include predictions of growth in Africa, which is evident in the strong industry support for the forthcoming Pumps, Valves & Pipes Africa (PVPA) Expo, which takes...
DIVERTER VALVE The series-725 diverter valve is designed to deliver significant time and cost savings in the field
A mining-specific diverter valve, designed to improve the efficiency of paste backfill operations, is experiencing significant interest in the South African market after being launched in the country at the Electra Mining Africa trade show, which was held from...
PVC VALVE The polyvinyl chloride union ball valve is a compact type of valve featuring full flow and axial pipe load block
Continuous development in the design and manufacture of plastic valves has created an opportunity for these valves in the potable-water market that was previously dominated by metal valves, says Cape Town-based piping systems company Alprene Plastic Products.
More
 
 
Latest News
Two influential US senators, central to the so-called ‘chicken war’, have announced their intention to pursue amendments to the African Growth and Opportunity Act (Agoa) to secure greater access for US poultry into the SA market. “We believe passionately in Agoa’s...
The Independent Communications Authority of South Africa (Icasa) on Friday published the findings of a discussion document on South Africa’s television and radio local content environment. Icasa last year requested industry input as it reviewed and revamped...
Buying the catering unit of cash-strapped state airline South African Airways (SAA) could work for Bidvest Group, its chief executive said on Friday. SAA is considering selling some of its units including its inflight and airport lounge catering business, Air Chefs,...
More
 
 
Recent Research Reports
Steel 2015: A review of South Africa's steel sector (PDF Report)
Creamer Media’s Steel 2015 report provides an overview of the key developments in the global steel industry and particularly of South Africa’s steel sector over the past year, including details of production and consumption, as well as the country's primary carbon...
Projects in Progress 2015 - First Edition (PDF Report)
In fact, this edition of Creamer Media’s Projects in Progress 2015 supplement tracks developments taking place under the Renewable Energy Independent Power Producer Procurement Programme, which has had four bidding rounds. It appears to remain a shining light on the...
Electricity 2015: A review of South Africa's electricity sector (PDF Report)
Creamer Media’s Electricity 2015 report provides an overview of State-owned power utility Eskom and independent power producers, as well as electricity planning, transmission, distribution and the theft thereof, besides other issues.
Construction 2015: A review of South Africa’s construction sector (PDF Report)
Creamer Media’s Construction 2015 Report examines South Africa’s construction industry over the past 12 months. The report provides insight into the business environment; the key participants in the sector; local construction demand; geographic diversification;...
Liquid Fuels 2014 - A review of South Africa's Liquid Fuels sector (PDF Report)
Creamer Media’s Liquid Fuels 2014 Report examines these issues, focusing on the business environment, oil and gas exploration, the country’s feedstock supplies, the development of South Africa’s biofuels industry, fuel pricing, competition in the sector, the...
Water 2014: A review of South Africa's water sector (PDF Report)
Creamer Media’s Water 2014 report considers the aforementioned issues, not only in the South African context, but also in the African and global context, and examines the issues of water and sanitation, water quality and the demand for water, among others.
 
 
 
 
 
This Week's Magazine
Today’s organisations execute projects within increasingly complex environments – particularly in the engineering sector. The ability to successfully execute these projects is what drives the realisation of successful projects and, ultimately, the achievement of...
SMART DISTRIBUTION Providing funds to introduce smart grid technologies in the absence of a clearly defined strategy will not result in the desired outcome
South Africa’s distribution grid is a twentieth-century relic, which must be changed to serve the country’s modern electricity needs, says South African National Energy Development Institute (Sanedi) Smart Grid Programme manager Dr Minnesh Bipath. “What we are...
There is a disparity in government funding provided to integrated transport networks – bus rapid transit (BRT) networks ¬¬– and that given to conventional bus services, says Putco executive director Thys Heyns. “We have neglected and strangled conventional bus...
The Johannesburg Social Housing Company (Joshco) is building 502 rental housing units, valued at R200-million, in Dobsonville, Soweto, which are scheduled for completion in June 2016.
Automotive component manufacturer and distributor Metair is centralising its research and development (R&D) work in Turkey, in an attempt to bolster the company’s ability to produce affordable start/stop batteries. The new R&D centre is part of an expansion plan in...
 
 
 
 
 
 
 
 
 
Alert Close
Embed Code Close
content
Research Reports Close
Research Reports are a product of the
Research Channel Africa. Reports can be bought individually or you can gain full access to all reports as part of a Research Channel Africa subscription.
Find Out More Buy Report
 
 
Close
Engineering News
Completely Re-Engineered
Experience it now. Click here
*website to launch in a few weeks
Subscribe Now for $96 Close
Subscribe Now for $96