Valve grinding includes the cleaning and inspection process, grinding process and inspection process.
1. The Cleaning And Inspection Process
Cleaning the sealing surface in the oil pan, using professional cleaning agent, while washing the damage of the sealing surface inspection. Micro-cracks which are difficult to be determined by naked eye can be detected by coloring method.
After cleaning, check the sealing surface of disc or gate valve with seat, check with red and pencil. Test Red Red, check the SEAL surface photocopying, seal surface seal; or with a pencil in the disc and seat sealing surface on a few concentric circles, then disc and seat close rotation, check the Pencil Circle Rub off, make sure the sealing surface is sealed properly. If the seal is not good, the standard plate can be used to test the disc or gate sealing surface and body sealing surface, determine the location of grinding.
2. Grinding Process
Grinding process is essentially a cutting process without a lathe. The depth of pits or small holes on the valve head or seat is generally less than 0.5 mm, which can be repaired by grinding method. The grinding process is divided into coarse grinding, medium grinding and fine grinding.
Rough grinding is to eliminate the sealing surface of the scratch, indentation, pitting and other defects, so that the sealing surface to get a high flatness and a certain degree of smoothness, for the sealing surface of the foundation. Rough grinding uses grinding head or grinding tool, using coarse abrasive paper or coarse abrasive paste, its particle size 80 #-280 # , coarse particle size, cutting volume, high efficiency, but deep cutting lines, sealing surface is rough. Therefore, the rough grinding as long as the head or seat of the valve can be removed smoothly.
Medium grinding is to eliminate the sealing surface of the coarse grain, further improve the sealing surface of the smoothness and smoothness. Using fine sand paper or fine grinding paste, the particle size is 280 #-W5, the particle size is fine, the cutting amount is small, which is helpful to reduce the roughness, at the same time should replace the corresponding grinding tool, grinding tool should be clean. After intermediate grinding, the valve contact plane should be bright. If you use a pencil in the valve head or seat to draw a few, the valve head or seat against the light rotation of a circle, the pencil line should be erased.
Fine grinding is the last process of valve grinding, mainly to improve the sealing surface finish. Fine grinding can be used w 5 or finer and oil, kerosene and other dilution, with the valve head against the valve seat grinding, without drama, this is more conducive to sealing surface. When grinding the general clockwise direction about 60-100, then the reverse direction about 40-90, gently grinding for a while, must be checked, to be polished shiny, and in the valve head and seat can see a circle of very thin line When the color reaches black and bright and black and bright, grind gently a few times with engine oil again, wipe with clean gauze can. After grinding, and then to eliminate other defects, that is, should be assembled as soon as possible, so as not to damage a grinding good valve head.
Manual grinding, whether rough or fine, is always through the lifting, down, rotation, reciprocating, tapping, reversing and other operations combined grinding process. Its purpose is to avoid the abrasive track repeat, so that the lapping tool and sealing surface to get uniform grinding, improve the smoothness and smoothness of the sealing surface.
3. Inspection Phase
In the grinding process is always through the inspection stage, its purpose is to grasp the grinding situation at any time, to make sure that the grinding quality meets the technical requirements. It should be noted that different valve grinding should be used to adapt to a variety of seal surface grinding tools to improve the efficiency of grinding, grinding quality assurance.
Valve grinding is a very careful work, need in practice to constantly experience, grope, improve, sometimes grinding very well, but after installation or leakage of steam, this is because in the grinding process there is the imagination of grinding partial Do Not hold the grinding rod vertical, askew, or lapping tool size angle error caused.
Post time: Jul-28-2021