With the rise of modern industry, especially modern petroleum, chemical industry, atomic energy industry, and large-scale power stations, pressure vessels are used for high-temperature, high-pressure, high-vacuum, chemical pumping, corrosion-resistant pumps, cryogenic and large-scale equipment, and corrosion-resistant places. Sheet seals continue to put forward new requirements, and various new materials and new structures continue to appear, and their sealing performance is also very different. In addition, pressure fluctuations, temperature changes, relaxation of bolt pre-tightening force, flange inclination, misalignment, sealing surface defects, and medium corrosion will all have a great impact on the sealing effect.
Corrosion-resistant chemical centrifugal pump shaft seals generally have two types: packing seal and mechanical seal. How to correctly select the appropriate gasket according to the working conditions and how to install it correctly is the key to ensuring the sealing effect of the chemical pump. Today, the editor focuses on how to correctly install the corrosion-resistant chemical centrifugal pump sealing gasket.
The following equipment should be prepared before installation:
1. Calibrated torque wrench, hydraulic tightening wrench or other tightening tools;
2. Steel wire brush, brass brush is better;
3. helmet;
4. Goggles
5. Lubricant
6. Other factory regulations, tools, etc.
Cleaning and tightening fasteners require a variety of specific tools. In addition, standard installation equipment must always be used and good safe operation methods must be followed.
1. Check and clean up:
①Remove all foreign impurities and debris from the gasket pressing surface, various fasteners (bolts, studs), nuts and gaskets;
②Check the fasteners, nuts and gaskets for burrs, cracks and other defects;
③Check whether the flange surface is warped, deformed, radially scratched, scratched by deep tools, or other defects that affect the correct seating of the gasket; if a defective original is found, it should be replaced in time, such as whether to replace it If you have any questions, please contact the sealing manufacturer in time.
2. Align the flange:
Make the flange face and the bolt hole align, and report any situation where the front face cannot be obtained.
3. Install the gasket:
①Confirm that the gasket meets the specified size and specified material;
②Check the gasket to ensure that there are no defects;
③Carefully insert the sealing gasket between the two flanges;
④ Confirm that the gasket is in the center position between the flanges;
⑤Unless the gasket installation instructions require the use of adhesives or anti-sticking agents, it cannot be used privately;
⑥ Align the flange surface to ensure that the gasket is not punctured or scratched.
4. Lubricate the stressed surface:
① Only the specified or approved lubricants are allowed to be used in the lubrication area;
②Spread enough lubricant on the bearing surfaces of all threads, nuts and gaskets;
③Ensure that the lubricant does not pollute the flange surface or the surface of the gasket.
5. Install and tighten bolts:
① Always use the right tools;
②Use a calibrated torque wrench or other tightening tools that can control functions;
③Consult the technical department of the seal manufacturer regarding torque requirements and regulations;
④ Follow the "cross symmetry principle" when tightening the nut;
Tighten the nut according to the following 5 steps:
The first step: the initial tightening of all nuts should be done manually, and the larger nuts can be tightened with the aid of a small hand wrench;
Step 2: Tighten each nut to approximately 30% of the required total torque;
The third step: Tighten each nut to approximately 60% of the required total torque;
Step 4: Use the "cross symmetry principle" to tighten each nut again to reach 100% of the required total torque
Note: For large-diameter flanges, the above steps can be performed more times;
Step 5: Tighten all the nuts one by one in a clockwise direction at least once to achieve all the required torque.
6. Tighten the bolts again:
① Consult the technical department of the seal manufacturer for guidelines and suggestions on re-tightening the bolts;
②Non-asbestos gaskets and gaskets containing rubber components that have been used at high temperatures must not be tightened again (except as otherwise specified);
③ Fasteners that have corroded thermal cycles need to be tightened again;
④ The re-tightening operation should be carried out under ambient temperature and atmospheric pressure.
