Quality standards for diaphragm pumps and maintenance standards for diaphragm pumps

In the use of various types of diaphragm pump products, it is common to encounter damage to diaphragm pumps due to wear or corrosion due to usage time. After damage, diaphragm pumps need to be repaired. So, what are the maintenance standards for diaphragm pumps?

① The valve seat and valve head of the inlet and outlet valve should have a good matching line, with a width of 0.25-2.00mm, and there should be no defects such as rust or pitting on them. If the requirements are not met, a combination of machining and centering tapping method can be used for repair. When the rust is severe, the valve seat should be replaced.

② The diaphragm should be smooth, without scratches, and have the required elasticity

③ The pressure regulating valve core of the control valve is tightly matched with the valve seat, and the kerosene leakage test is conducted for 5 minutes, with no more than one drop of leakage. According to the damage situation, corresponding repair methods such as machining, centering and tapping, or grinding can be adopted. If it cannot be repaired, replace it.

The quality standards and maintenance methods for the oil replenishment valve are the same as those for the pressure valve.

④ The tolerance of the fitting dimensions between the plunger and guide tube of the pump body component is H8/g8, with a roundness of 0.02mm and a straightness of 0.02mm. The surface roughness is Ra0.8 μ m and the surface hardness is 45-55HRC.

The major overhaul wear of the plunger with a coaxiality of 0.02mm between the mating shaft diameter and the positioning shaft diameter is 0.01D (D is the diameter).

⑤ The coaxiality between the inner diameter and outer diameter of the guide sleeve is 0.02mm. Fit the plunger with a tolerance surface of 1-10 on both sides. The sealing ring should have good elasticity, no aging or cracking, and no scratches or damage to the mating surface with the plunger.

⑥ The fit tolerance between the crankshaft main journal, crankshaft journal, and bearing shell is G7/h6, with a roundness of 0.02mm and a straightness of 0.02mm. The surface roughness value is Ra0.8 mm. The wear of the main journal and crankshaft during major overhaul is 0.04 times the diameter.

⑦ The mating surface between the crankshaft bearing shell and the bearing shell has no pulling or fuzzing, and the surface roughness is Ra0.8 μ m. The perpendicularity of the guide hole on the surface of the bearing shell is 0.02mm.

After the combination of the two bearing shells, the coaxiality of the guide holes at both ends is 0.02mm.

⑧ The tolerance of the fitting size between the crankshaft bearing and the bearing shell is rock, and the tolerance of the fitting size with the crankshaft neck is H7/g7, with a surface roughness of Ra1.6 μ m. The tolerance of the fit size between the bearing key groove and the positioning key is H7/g7.

⑨ The tolerance of the fitting size between the crankshaft sleeve and the main journal is rock, and the surface roughness is Ra1.6 μ m. The coaxiality between the inner and outer diameters is 0.02mm.

⑩ The tolerance of the fitting dimensions between the central shaft and the shaft sleeve is -. Roundness is 0.02mm, straightness is 0.02mm, surface roughness is Ra0.8 μ m, quenched and tempered. The coaxiality between the mating journal and the locating journal is 0.01mm. The overhaul grinding amount of zui is 0.04 times the diameter.

⑩ The surface roughness of the central shaft sleeve is Ra1.6 μ m. The coaxiality between the inner diameter and outer diameter is 0.02mm.