Analysis of measures taken against external causes of mechanical seals for hydraulic pumps

In the above, the external reasons affecting the mechanical seals for hydraulic pumps for hydraulic pumps have been analyzed. In this paper, Dalan Hydraulics will specifically analyze how to eliminate the external causes of mechanical seals for hydraulic pumps:

1. Due to the existence of unbalanced axial force, the whole shaft is swayed to the suction port, causing the mechanical seal to lose its sealing effect. Commonly used measures are:

1 open the balance hole on the impeller;

2 The pump body is equipped with a balance tube and the like.

2. Common measures for unreasonable design or no auxiliary flushing system are:

1 Design an auxiliary flushing system as far as practicable. The flushing pressure is generally required to be higher than the sealing chamber pressure by 0.107~0.11MPa. The sealing chamber pressure should be calculated according to the structural form of each pump and the system pressure.

When the pressure of the 2-axis seal chamber is very high or the pressure is close to the highest limit of the seal, the liquid can be led to the low pressure zone by the seal chamber, so that the shaft seal liquid flows to take away the friction heat.

3 Properly configure piping and accessories according to the operating conditions of each pump. Such as coolers, orifices, filters, valves, flow indicators, pressure gauges, temperatures, etc.

4 In fact, the reliability and life of the seal depend to a large extent on the configuration of the seal assist system, and the sealing effect of the mechanical seal on the cause of insufficient machining precision of the pump shaft, bushing, pump body and seal cavity. It is also very unfavorable, and strict checks should be made in these areas.

3. Measures to eliminate pump vibration: When the auxiliary equipment such as hydraulic pump, motor, base, and on-site pipeline are installed on site, it is necessary to strictly control and eliminate the vibration source.

4. The measures to eliminate cavitation at the inlet of the pump are as follows:

1 Improve the cavitation performance level of the pump to meet the cavitation performance requirements of the field device.

2 The pump should be operated below the allowable aspiration height to ensure safe and reliable operation of the entire unit.

3 The impeller is made of anti-cavitation material, such as: 2Cr13, rare earth alloy cast iron, high nickel-chromium alloy material, etc., which is much better than ordinary cast iron.

----- Editor-in-Chief: Dalan Oil Pump Motor 02-Procurement Consultant

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Pyrite as Fillers Used in Grinding Wheels/ Abrasive Tools

Ablation grinding wheel / abrasive( filling agent )

PYRITE__As fillers used in grinding wheels/ abrasive tools


Place of Origin: Henan Luoyang, China

Pyrite, Iron pyrites, pyrites lump, Ferro sulphur, Pyrites powder.

Product Description

Detailed introduction:  is filling agent for ablating grinding wheel abrasive, which can effectively reduce the grinding wheel temperature during ablation, improve the heat resistance, and prolong the service life of the grinding wheel.

Formation of a protective layer 
(1)The reaction absorbing oxygen occurs between 400 and 475 degrees, thereby reducing the oxidation of resin, reducing the oxidation burn of workpieces, and prolonging the working life of grinding wheels at high temperature.

4 FeS2 + 11 O2→2 Fe2O3 + 8 SO2 
(2) 4 FeS + 7 O2→4 Fe2O3 + 4 SO2 

400-475 degrees is a limit that the grinding wheel can easily reach. The above reaction creates an oxygen-free and hypoxic environment for the grinding wheel at the micro level, thereby improving the high-temperature performance of the grinding wheel.
Decomposition reaction occurs at 650-degree heat absorption, thereby reducing the working temperature of the grinding wheels.

FeS2→FeS + S 
(3) It enters the melting state at about 1100 degrees, which becomes a good lubricant to protect the grinding wheel FeS(s)→FeS(l).

(4)Sulfur, sulfur dioxide and sulfur trioxide react with the workpiece surface to form FexSy:


S: 48%min, FE: 42%min, SIO2: 3.0%max, PB: 0.1%max,

ZN: 0.1%max, AS: 0.1%max, . C: 0.3%max, CU: 0.2%max,

H20: 1.0%max, SIZE: 95%min

Granularity: (0-3)mm/(3-8)mm/(3-15)mm/(15-50)mm or other particle size.

Packing: 25KG/500KG/1000KG/BAG or 1000KG/BAG or other packaging.

Note: if there are special requirements, the product can be customized according to clients` requirements.

Iron Sulphide For Resin Grinding Wheel---LHT(SL)

Iron sulphide for resin grinding wheel Pyrite, Iron pyrites, pyrites lump, Ferro sulphur, Pyrites powder