The wear parts of the Gear Oil Pump mainly include the drive shaft and bushing wear, the passive gear center hole and the shaft pin, the pump casing inner cavity and gear, the gear end face and the pump cover. After the lubricating oil pump wears, it should be disassembled and decomposed, the wear parts and extent should be found out, and the corresponding measures should be taken to repair it.
First, the repair of the drive shaft and bushing after wear
After the drive shaft and bushing of the gear pump wear out, the matching clearance increases, which will affect the pump oil quantity. In this case, the normal fit clearance can be restored by repairing the drive shaft or bushing. If the drive shaft wears slightly, simply press the old bushing and replace it with a standard size bushing. The clearance can be restored to the allowable range. If the drive shaft and the bushing are severely worn and the clearance is seriously exceeded, the bushing must be replaced, and the drive shaft should be chromed or vibrated to increase its diameter, then ground to the standard size, and the bushing is restored. Coordination requirements.
Second, the repair of the lubricating oil pump casing repair of the crack: the shell crack can be repaired by casting 508 nickel-copper welding rod. The weld must be tight and the air hole is not more than 0.05 mm.
Repair of the drive shaft bushing hole and the driven shaft hole wear: After the drive gear shaft bushing hole is worn, the wear marks can be used to eliminate the wear marks, and then the bushing is enlarged to the corresponding size. The driven shaft hole wear also eliminates the wear marks by reaming, and then the driven shaft is prepared according to the actual size of the reamed hole.
Repair of the inner cavity of the pump casing: After the inner cavity of the pump casing is worn, it is generally repaired by the inner cavity inserting method, that is, the inner cavity is required to be inlaid with cast iron or steel bushing. After the insert is set, the inner cavity is pulled to the required size, and the bushing of the extended end face is ground to make it flush with the pump casing joint surface.
Valve seat repair: The pressure limiting valve has two kinds of ball valve and plunger valve. After the spherical seat gear pump is worn, a steel ball can be placed on the valve seat, and then the steel ball is gently tapped with a metal rod until the ball valve is in close contact with the valve seat. If the seat is severely worn, it can be reamed to remove the wear marks, and then the upper method is used to make it close. After the plunger seat is worn, a small amount of valve sand can be placed for grinding until it is tight.
Third, the repair of the pump cover
Repair of the working plane: If the working plane of the pump cover is less worn, the wear marks can be eliminated by manual grinding, that is, put a little valve sand on the platform or thick glass plate, and then put the pump cover on it for grinding until the wear marks are eliminated. The working surface is flat. When the working surface of the pump cover wears more than 0.1 mm, it should be repaired by turning and grinding first.
Repair of the drive shaft bushing hole: Repair of the drive shaft bushing hole wear on the pump cover is the same as the repair of the housing drive shaft bushing hole wear.
Fourth, the use of gears to flip
The gear pump gear wear is mainly in the tooth thickness, while the gear end face and the tooth top wear are relatively light. The gears are worn on one side in the tooth thickness, so the gear can be turned 180 degrees. When the gear end face is worn, the end surface can be flattened and the lubricating oil pump casing joint surface is ground to ensure that the gap between the gear oil pump end face and the pump cover is within the standard range.

The process of reassembly after disintegration:
(1) The parts must be cleaned with kerosene and lubricated when loading the parts in the gear pump body.
(2) Parts must not be brought into any debris and pollution.
(3) When assembling the upper and lower bearing housings and the main and passive gears, the difference between the gears of each pair of bearing seats and each pair of gears shall not exceed 0.005mm.
(4) The paper pad is adjusted on both sides of the gear. The gap is too large to be easily returned, which reduces the efficiency. If it is too small, the temperature of the oil pump will rise or the oil pump will die.
(5) Assemble the flexible graphite ring or mechanical seal “O” ring with a special sleeve gear pump. The flexible graphite ring must be handled gently, and it is strictly forbidden to bump and smash to prevent chipping or deformation.
(6) After the assembly is completed, it is used to rotate the driving gear to check whether there is any unevenness or sudden jump. And the input shaft is rotated by the hand gear pump, which should be flexible and without blockage.

(1) KCB gear pump body castings and end cover brackets shall have no defects such as air holes, blisters, slag inclusions and cracks.
(2) The machining surface of the KCB gear pump body should be smooth and free of scratches and grooves. If there is slight pulling and scratching, it can be repaired by semi-circular oil stone; the center line of the inner hole and the two end faces become 0.02% vertically.
(3) The hydraulic pressure test of the KCB gear pump is 1.5 times of the working pressure, and it is kept for 5 minutes without leaking.
(4) Measuring the parallelism of the two axes of the end cap, it should be no more than 0.01%; the deviation of the hole and the center distance is ±0.04mm. The center line of the two holes of the end cover is perpendicular to the processing end face, and the value is not more than 0.03%.
(5) When assembling the KCB gear pump, the tightening bolts should be symmetrically and evenly unidirectionally, and the rotor should be moved tightly when the rotor is tight. If the rotor is not moving, the adjustment gap should be loosened and re-tightened.

Stainless steel gear pump material selection:
Common stainless steel gear pumps are mainly made of stainless steel such as 304, 316 and 316L. All stainless steel gear pump parts are all processed by special process chemistry, which has high corrosion resistance, wear resistance and pressure resistance. The main products of stainless steel gear pump are forging products, ordinary sand casting products, precision casting products and silica sol casting products. The appearance is exquisite, beautiful, low noise and long service life. It is the first choice for chemical and corrosive equipment. KCB series stainless steel gear pump gear adopts involute helical gear structure, which is assembled with corrosion-resistant fluorine rubber skeleton oil seal and polytetrafluorocarbon high temperature packing seal. It has good sealing effect and high temperature resistance. Stainless steel corrosion-resistant mechanical seals can be used for special working conditions.
The SS gear pump is suitable for lubricative liquids with mild corrosive or hygienic conditions without solid particles and fibers, temperature not exceeding 280 ° C and viscosity not exceeding 2000 cst. In order to adapt to different working conditions, a variety of stainless steel pump products can be designed for use with different corrosive media.
Model 316—After 304, the second most widely used steel grade is used primarily in the food industry and surgical equipment, adding molybdenum to give it a special structure that resists corrosion. It is also used as “ship steel” because it has better resistance to chloride corrosion than 304. SS316 is commonly used in nuclear fuel recovery units. 18/10 grade stainless steel also generally meets this application level.
Advantages of stainless steel gear pumps:
1. Stainless steel gear pump has excellent corrosion resistance.
2. The device is repaired. The small stainless steel gear pump can be self-contained, and the large stainless steel gear pump is usually equipped with automatic coupling to stop the automatic device, and the device and maintenance are quite convenient.
3. Continuous operation time is long. Since the stainless steel gear pump is coaxial with the pump and the motor, the shaft is short, and the rotating parts are light in weight, the load (radial) received on the bearing is relatively small, and the life is much longer than that of the ordinary pump.
4. Compact structure and small air volume. Because the stainless steel pump works under submerged liquid, it can be directly installed in the sewage tank. It does not need to build a special pump room to install pumps and machines, which can save a lot of land and infrastructure costs.

NYP Stainless Steel Rotary Gear Pump is a kind of new positive displacement pump, and is designed according to the different fields of petroleum, chemical industry, paint, medicine, foodstuff and so on. It widely applies to a variety of mediums with different property and viscosity because of special structure and selected different pumps’ materials.If pumping hazardous, hard-to-handle liquids and for applications, the pump can be fitted with a magnetic driver – NYP Mag-Drive Internal Gear Pump.
The SS Gear Pump non pulsating constant flow, therefore no vibrations on fittings, valves or couplings. Full performances are available in either direction of rotation. It can also be requested with heating jackets, with ports at 90° or 180°.

Model:NYP
Flow:0.5-250m³/h.
Max.pressure:1.0Mpa
Temperature:≤300℃
Manufacturer:China Saiken pumps
Viscosity:1.0-300000cst
Pump speed:60-1450r/min
Material:Cast iron,cast steel,ductile iron,SS304,SS316,SS316L
Medium:Resins, molasses, glue, bitumen……

Heavy-duty construction optimized for rare maintenance. Produced in different versions depending on the specific application. Used by transfer, dosage, processing, load and unload. In chemical, ink, paint, construction, chocolate and oil-industry, in refineries and storage facilities.

Advantages:
* Self-priming.
* The capacity is directly proportional to the rotation speed.
* Non pulsating constant flow, therefore no vibrations in fittings, valves or coupling.
* No foaming or churning of the liquid.
* Only one shaft seal or with magnetic coupling.
* Heating jacket around the casing in one cast.
* Full performance is available in either direction of rotation.
* The casing can be rotated and delivered with 90° or 180° (in-line) ports.
* Relief valve against over-pressure incorporated in the pump.
* Heavy-duty construction optimized for rare maintenance

When conveying the non-lubricating and low-viscosity medium, the gear oil pump should choose the material of the over-current part of the gear and the shaft according to the corrosiveness of the conveying medium, and choose the reasonable quenching and tempering problem, such as whether the gear is quenched or nitrogen. Or hard chrome plating and so on. The sealing can be combined with a PTFE skeleton oil seal and a PTFE packing seal, or a hard alloy mechanical seal or a silicon-to-ink mechanical seal. It is also necessary to use a high pressure, large spring, mechanical seal with a large compression. The key is that the gear and shaft are selected under reasonable conditions. The material of the bushing is also very important. Generally, when the gear pump is used to transport high-viscosity and non-lubricating medium, the bushing should be made of silicon carbide or zirconia ceramic or tin bronze. Material. Different from conveying high-viscosity and non-lubricating medium, the key of the gear oil pump in conveying the viscosity medium is that the matching clearance of each part inside the pump must be reasonable, and the matching clearance must be small. If the matching clearance is too large, the gear oil pump will not be pumped. The medium, or the flow is not enough, the pressure is not enough, etc., the clearance is too small, and it is particularly easy to cause the gear pump to lock up.