The calculation of grease injection for forged steel gate valves requires comprehensive consideration of valve body structure, sealing characteristics, and grease performance.
The calculation of its grease injection amount is mainly based on two core dimensions: valve body volume compensation and sealing surface lubrication requirements. Valve body volume refers to the space in the valve chamber that can accommodate lubricating grease, usually calculated through geometric parameters; The sealing surface area determines the amount of lubricating grease required for coverage.
The industry standard formula is: G=V × ρ+S × k
among which
G: Total fat injection amount (g)
V: Valve body volume (cm ³)
ρ: Lubricating grease density (g/cm ³, usually 0.9-1.1)
S: Sealing surface area (cm ²)
k: Lubricating grease coefficient per unit area (0.02-0.05g/cm ²)
For standard forged steel gate valves, the valve body volume can be estimated using the following formula:
V=π× (half D): ml − citationref=”2″ data=”citationList” × L × f
among which
D: Valve seat diameter (mm)
L: Valve chamber length (mm)
f: Structural correction factor (0.7 for wedge gate valves and 0.8 for parallel valves)
The sealing surface area is related to the valve type, and the formula for rising stem gate valves is as follows:
S=π×D×H×n
H: Sealing surface width (mm)
n: Number of sealing surfaces (usually 2)
During the operation, pay attention to controlling the grease injection pressure. It is recommended to use a high-pressure grease gun (pressure ≥ 20MPa) to ensure that the lubricating grease fully fills the valve chamber dead corner.
Fat injection frequency: Supplement every six months under normal working conditions; Supplement every three months in corrosive environments. Excessive grease injection is not allowed. Exceeding the calculated value by 30% may result in excessive compression deformation of the sealing surface and increased resistance to valve stem movement.
In practical applications, it is recommended to combine the technical manual provided by the valve manufacturer for accurate calculations, and regularly check the filling status of the lubricating grease through the observation hole of the grease nozzle. For critical pipeline valves, ultrasonic testing can be used to verify the effectiveness of grease injection.