GB steel gate valve
The opening and closing part of the GB gate valve is a gate. The direction of movement of the gate is perpendicular to the direction of the fluid. The gate valve can only be fully opened and fully closed, and cannot be adjusted and throttled. The gate valve has low fluid resistance, and the sealing surface is less washed away and eroded by the medium. , It is more labor-saving to open and close, the flow direction of the medium is not restricted, does not disturb the flow, does not reduce the pressure, the shape is simple, the structure length is short, the manufacturing process is good, and the application range is wide.
The types of national standard cast steel gate valves can be divided into wedge gate valves and parallel gate valves according to the sealing surface configuration. Wedge gate valves can be divided into: single gate, double gate and elastic gate; parallel gate The disc type gate valve can be divided into single disc type and double disc type. According to the thread position of the valve stem, it can be divided into two types: bright stem gate valve and dark stem gate valve.
The operation methods of cast steel gate valve are: manual, gear transmission, electric, pneumatic, etc.
The GB gate valve is suitable for pipelines in various working conditions such as the petroleum, chemical, pharmaceutical, fertilizer, and power industries with a nominal pressure of PN1.6 ～ 6.4MPa and an operating temperature of -29 ～ 600 ℃. Regulation and throttling. Applicable media: water, oil, steam, acid media, etc.
Structural characteristics and advantages:
The structural design of the gate valve is reasonable, the seal is reliable, the passage is smooth, and the flow resistance coefficient is small.
The sealing surface of the gate and valve seat is made of iron-based alloy or Stellite cobalt-based hard alloy, which is wear-resistant, high-temperature resistant, corrosion-resistant, good abrasion resistance and long service life.
It adopts wedge-type elastic brake plate or steel wedge-type single brake plate structure. Rolling bearings are installed in medium and large calibers. The switch is flexible and easy to open and close.
The valve stem is quenched and tempered and the surface is nitrided to have good corrosion resistance, abrasion resistance and abrasion resistance.
Various piping flange standards and flange sealing surface types can be used to meet various engineering needs and user requirements.
The valve body has a full range of materials, and the packing and gasket can be reasonably selected according to the actual working conditions or user requirements, which can be applicable to various pressure, temperature and medium working conditions.
The installation and maintenance of gate valve should pay attention to the following matters:
Handwheels, handles and transmission mechanisms are not allowed for lifting, and collision is strictly prohibited.
The double-gate gate valve should be installed vertically (that is, the valve stem is in the vertical position and the handwheel is at the top).
The gate valve with the bypass valve should be opened before opening (to balance the pressure difference between the inlet and outlet and reduce the opening force).
The gate valve with transmission mechanism shall be installed in accordance with the instructions of the product instruction manual.
If the valve is used frequently, lubricate at least once a month.
Installation and use of national standard gate valve
1. Before installation, check the valve cavity and sealing surface, etc. No dirt or sand particles are allowed to adhere;
2. The bolts at each connection part should be evenly tightened;
3. Check that the packing parts are tight, not only to ensure the tightness of the packing, but also to ensure that the gate can be opened flexibly;
4. Before installing the valve, the user must verify the valve model, connection size and media flow direction to ensure consistency with the valve requirements;
5. When installing the valve, the user must reserve the necessary space for the valve drive;
6. The wiring of the driving device must be performed according to the wiring diagram;
7. The gate valve products must be maintained regularly, and must not be bumped and squeezed at will, so as not to affect the seal.
Design and manufacturing standard: GB / T 12234-2007
Structure length standard: GB / T 12221-2005
Connecting flange standard: GB / T 9113
Pressure temperature grade: GB / T 12224-2005
Test inspection standard: GB / T 13927-2008
| Nominal pressure |
|Test pressure (MPa)||Applicable temperature (℃)||Applicable medium|
|Strength test||Seal test||WCB||Cr5Mo||1Cr18Ni9Ti|
|1.6||2.4||1.8||≤425||≤540||≤600||Water, oil, steam, acid medium|
Parts materials and working conditions:
|Part Name||Material grade|
|Valve body||WCB||ZGCr5Mo||CF8|| CF8M |
|cap||WCB|| 12CrMoV |
| 304 |
| 316 |
|CF3|| CF3 |
|Gasket, gasket ring, sealing ring||Covering gasket, 304, reinforced flexible graphite|
|filler||Reinforced flexible graphite|