Comparison of main manufacturers of domestic safety valves and selection of connection sizes

There are many manufacturers of safety valves in China, and the connection sizes are mostly not uniform. Mainly divided into the following major categories:


(1) The general category based on JB/T2203-1999 "spring-type safety valve structure length". At present, most domestic safety valve manufacturers are designed and produced according to this standard. However, this standard is not perfect, the specifications are not complete, the micro-open safety valve Zui large nominal diameter is D NI 00, full-open safety valve zui large nominal diameter DN200, the lack of DN65, DN125 two specifications. According to the specifications of the safety valve produced by our factory and the information we have mastered, the nominal diameter of the micro-opening safety valve is DN250, and the nominal diameter of the full-open safety valve is DN400. According to my research, the connection sizes of various manufacturers are not uniform, such as the DN150 full-open safety valve, which is different. In order to have a uniform standard, the user can exchange the same specifications during the selection and installation. It is recommended that the Hefei General Machinery Research Institute revise the JB/T2203-1999 "Spring-type Safety Valve Structure Length". It is recommended that the design institute and users select according to the standard, and the safety valve manufacturer designs and manufactures according to the standard.

(2) The American standard system based on API526 "Flanged Steel Safety Relief Valve". The safety valve connection size of domestic imported chemical equipment is generally in accordance with this standard, as shown in Figure 5. The nominal diameter of this standard is DN25~ DN200( l"~ 8"), the nominal pressure is 2~42MPa, and the throat diameter is from D-T (9.5~146mm). This standard is more scientific and standardized, and considers pressure, materials, temperature, and throat diameter. According to the throat diameter to determine the specifications, the same throat diameter can have several specifications, on the contrary, the same specification may have several throat diameters to choose from. For example, DN100~DN150 (4"~6") throat diameters are available in L, M, N and P. With the continuous advancement of international trade and the localization of imported equipment, the standard will be greatly promoted in China. The standard has not yet been converted into a national standard.

(3) Pilot Operated Pressure Relief Valves series based on the internationally influential Anderson Greenwood & Co.. Domestically referred to as a pilot-operated safety valve, as shown in Figure 6, the pilot-operated safety valve consists of a main valve and a pilot valve, and the pilot valve operates the main valve to open and close. The valve has a large displacement; it is not affected by the back pressure; it can be operated at a very close to the opening pressure; the opening and closing pressure difference is small. Generally applicable to natural gas pipelines, etc. At present, there is no pilot safety valve standard and connection size standard in China. And this type of valve has just been developed and has not been widely promoted. According to the experience of our factory and the information we have, most domestic manufacturers design and manufacture according to the company's data.
(4) The safety valve designed and developed by the 11th Research Institute of China Aerospace Industry Corporation is a self-contained system. The HT series safety valve developed by Aerospace Eleven has many varieties, including HTO ordinary safety valve (as shown in Figure 1), HTB balanced bellows type safety valve, HTR bleed valve, HTN special safety valve, HTGS high performance steam safety valve. . HTXY liquid pressure relief valve, HTXD pilot safety valve, etc., and good performance. However, except for the HTXD series pilot-operated safety valve and the connection size of Anderson Greenwood, the rest is different from the American standard and the national standard. Please be careful when choosing this.

(5) The A-type and TA-type closed full-opening spring-type safety valves designed and developed by Lanzhou Refinery are a system. The series diameter is DN25~DN150 (1”~6'), the nominal pressure is 1.6~4.0MPa, and the throat diameter is D~R(9.5-115mm). The connection size of the system is different from the American standard and the national standard. Lanlian special.

(6) A series of impulse safety valves for boilers, power station equipment, and temperature and pressure reducing devices (as shown in Figure 8). Such as Harbin Boiler Factory, Dongfang Boiler Factory, Wuhan Boiler Factory, Qingdao Power Station Auxiliary Machine Factory and other special safety valves. These types of valve structures and connection sizes are generally different from manufacturer to manufacturer and may be partially identical. When choosing, be sure to pay attention to the difference between the throat diameter and the connection size.