Spring safety valve opening, closing operation is medium pressure change and the spring preload to its inlet end of the spool to automatically open and close. When the medium pressure (internal pressure) rises to the lifting force is larger than the spring preload, the spool against the spring preload automatically open A28H spring safety valve, venting excess media, the internal pressure drop, and because force of the spring, when the internal pressure dropped to a safe value A28H valve, valve automatically closes the safety valve, the discharge stops. Safety valve means opening height is greater than the channel diameter equal to 1/4 of the safety valve. This part of the operating characteristics of the two-acting valve safety valve. The main parameters of the safety valve displacement, the displacement depends on the caliber of the valve seat and valve opening height, from the opening of different height, is divided into Weiqi the entire Kai two. Weiqi is the valve opening height for the seat throat diameter of 1/40 ~ l / 20. Entire Kai is the valve opening height for the seat throat diameter of 1/4. Weifang valve safety valve means opening height greater than or equal 1/4 channel diameter of the safety valve. This part of the operating characteristics of the two-acting valve safety valve. The main parameters of the safety valve displacement, the displacement depends on the caliber of the valve seat and valve opening height, from the opening of different height, is divided into Weiqi the entire Kai two. Weiqi is the valve opening height for the seat throat diameter of 1/40 ~ l / 20. Entire Kai is the valve opening height for the seat throat diameter of 1/4. A28 / H valve manufacturer, Everbright valve manufacturers, safety valve provided by Shandong China Everbright Limited valve. Valve Co., Ltd. Shandong China Everbright (www.sdgdfm.com) Shandong Weifang, ball leader, over the years, the company is implementing the scientific management, innovation and development, the principle of honesty and trustworthiness, and satisfy customer needs. Everbright valve leadership with the staff warmly welcome all inquiries negotiations to create a better future for China Everbright valve.