Hydraulic piston pumps are used in equipment such as pavers, concrete mixer trucks, rollers, coal mining machinery, concrete pumps, pharmaceutical machinery, etc. The efficiency of the hydraulic system in operation mainly depends on the volumetric efficiency of the hydraulic pump. When the volumetric efficiency drops to 72%, routine maintenance is required, including replacing bearings and aging seals, and replacing or repairing friction pairs that exceed the fit clearance to improve their performance. Therefore, plunger pump manufacturers remind that in order to extend and improve the service life of hydraulic plunger pumps, the following points must be noted:

 

1、 The pumps in piston pumps are divided into two types: pressure supply type and self-priming type:

 

1. The self-priming hydraulic pump has strong self-priming ability and does not require external oil supply. The hydraulic oil tank for pneumatic oil supply must wait for the hydraulic tank to reach the required air pressure before operating the machine after each start-up.

 

2. Pressure oil supply hydraulic pumps mostly use oil tanks with air pressure, and some hydraulic pumps themselves have oil replenishment pumps to provide pressure oil to the hydraulic pump inlet.

 

The higher the cleanliness of hydraulic oil, the longer the service life of hydraulic pumps.

 

2、 Inspection and repair of friction pairs:

 

According to the replacement standard of piston pump parts, when various clearances of the parts exceed the tolerance, the plunger rod and cylinder body hole in the plunger pump can be repaired according to the following three points:

 

2. The repair method for the cylinder body and copper sleeve with fusion bonding method is as follows:

 

(a) Use grinding rods to manually or mechanically grind and repair cylinder holes.

 

(b) Use a coordinate boring machine to re bore the cylinder body hole;

 

(c) Use a reamer to repair the cylinder bore.

 

1. Adopting "surface engineering technology", the method is as follows:

 

(a) Electroplating technology: plating a layer of hard chromium on the surface of the plunger.

 

(b) Electric brush plating technology: Brush plating wear-resistant materials on the surface of the plunger.

 

(c) Thermal spraying, arc spraying, or electric spraying: spraying high carbon martensitic wear-resistant materials.

 

(d) Laser cladding: depositing high hardness and wear-resistant alloy powder on the surface of the plunger.

 

If the cylinder body is fitted with a copper sleeve, it can be repaired by replacing the copper sleeve. Firstly, trim the diameter of a set of plunger rods to a uniform size, and then polish the outer diameter with sandpaper of 1000 # or above. Three methods for installing copper sleeves on cylinder bodies.

 

(a) Cylinder body heating hot installation or copper sleeve low-temperature freezing extrusion, interference fit assembly.

 

(b) Using Loctite adhesive for assembly, this method requires a groove on the outer diameter surface of the copper jacket.

 

(c) Tap the cylinder hole, thread the outer diameter of the copper sleeve, apply Loctite adhesive, and screw it into the assembly.

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