CNC machine tools ,large vertical lathes, drill press, milling lathe grinding machine , Welding machine , separate metal working workshops and many general machine tool etc.
Material analysis, PMI Material analysis. Chemical analysis. Low temperature test, Tensile Test ,Impact test, Hardness test. Wall thickness test, roughness test. Torque test. NDT Inspection (MT,PT,UT,RT). HIC test ,SSC test . Intercrystalline corrosion Test ,Uniform corrosion Test.
The company is the first one to pass ISO 9001(2008),ISO 14001 ,OHAS 18001 international quality system certificate, China pressure pipe safety registration certificate (AZ), European Union safety registration certificate (CE0036), and American Petroleum Institute Certificate (API 6D) and (API607) .
We are one of the member unit of China Valve Association as well as China Gas Association, member unit of first class supplying network of CNPC and member unit of fittings supplying network of State Power Corporation.
EDVC VALVE CO.,LTD.is a specialized in valve manufacturing enterprise with more than 15 years of history.We main produce Top Entry Ball Valve, Fully Welded Ball Valve, Arc Valve, Aluminum Bronze Valve, Automatic Recirculation Valve, Orbit Ball Valve, Safety Valve, Globe Valve, Tilting Disc Check Valve and Rising Stem Ball Valve etc.
The products have been exported to Austria, France, Germany, United Kingdom ,America, Middle East and Asia, Africa . areas and countries. Moreover, the products are widely used in the fields of oil & gas, Oil refinery, Petrochemical,power station ,Sewage treatment, pharmacy, Paper mills, pipeline industry , mining industry , chemical industry and environmental protection.
We are a professional manufacturer of valves in China, with the aim of "providing the first class products and services". On behalf of all of the members at EDVC Valve, we thank you for the opportunity to earn your business.
In order to prevent the water temperature from rising to a certain level, it will vaporize and form cavitation. Cause damage to the water pump. Install a recirculation system between the outlet of the feedwater pump and the water tank of the deaerator (or condenser). The recirculation system can be opened when the feedwater pump is just started or when the water supply is small to a certain extent. Part of the water is returned to the water tank of the deaerator to ensure that a certain amount of water (usually about 30% of the rated flow) passes through the pump without causing the water temperature in the pump to rise and vaporize. When the water supply is under normal conditions, the recirculation system is closed.
The centrifugal pump converts mechanical energy into pressure energy through the centrifugal force generated by the rotation of the impeller acting on the fluid in the pump. The pump requires minimum liquid flow to prevent overheating. If the predetermined minimum flow rate is not maintained, the pump may be permanently damaged.
Depending on the main flow rate, the main valve disc of the recirculation valve will be determined to be in a certain position. The stem of the main check valve passes a lever to transfer the action of the main disc to the bypass, and the bypass system is controlled by the bypass. At the same time, the flow rate of the circuit reduces the pressure to the value required by the outlet. When the main valve disc returns to the seat closed state, all the flow passes through the bypass (backflow). When the main valve disc rises to the top position, the bypass is completely closed and all pumps The flow rate flows to the process system.
1. When the main valve is completely closed and the bypass is in the fully open position, the pump is at the minimum continuous flow condition, which can effectively protect the pump from "cavitation";
2. As the main circuit check valve is gradually opened and the bypass is gradually closed, the sum of the process flow and the recirculation flow is greater than the minimum continuous flow of the pump;
3. As the process flow increases, when the main valve is in the fully open position, the bypass is completely closed.
Automatic recirculation valves, sometimes referred to as pump protection valves or minimum flow valves are installed on the outlet of a centrifugal pump discharge line. Their purpose is to prevent the pump from overheating by ensuring that there is a minimum flow through the pump at all times.
An automatic recirculation valve is a multifunctional valve whose primary purpose is to ensure that a pre-determined minimum flow is assured through a centrifugal pump at all times. This is important as centrifugal pumps suffer from over heating and cavitation and can be permanently damaged if they run dry.
If a high pressure pump is deadheaded, significant damage results for the pump or the system.Recirculation lines provide a means of relief for high pressure pumps when operated against a closed valve or other system obstruction.