JPS58122395A - Non-leakage pump - Google Patents

Abstract

PURPOSE:To prevent leakage by submerging the interior of a motor in the oil with a pressure equal to that of a pump working fluid so as to have no pressure difference in a penetration shaft section. CONSTITUTION:A rotor 7 is rotated in the oil with lubricating ability, therefore a normal bearing can be used. In addition, since the oil with lubricity is used, no adverse effect is expected to the stator winding 6 and the cooling is superior to air cooling. Bearings 8, 9 are lubricated with the oil for sealing. The leading terminal 10 of the stator winding 6 penetrates the winding air-tightly against the oil pressure, thereby no pressure difference is present at the penetration shaft section and leakage can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION In recent years, there has been an increasing demand for leak-free pumps in all fields. Conventionally, as this type of pump, a canned pump has been used in which the rotor portion of the electric motor is airtightly separated from the stator portion of the electric motor by a can made of a thin stainless steel plate. A disadvantage of this type of pump is that since the motor rotor rotates in the working fluid of the pump, solids, corrosive liquids, etc. in the working fluid can act on the motor rotor. It is also necessary for bearings to rotate in such liquids without lubricating oil. For this reason, special materials such as ceramics are used for bearings. However, the bearings wear out in a short period of time, causing problems such as play. Also,
Normally, the can is made of a non-magnetic but conductive material such as austenite or stainless steel, so there is a loss of magnetic lines of force, which reduces the efficiency of the motor.

The present invention solves these eight problems by sealing oil with electrical insulation and lubricating properties inside the electric motor.
The pressure of this oil is balanced with the pressure of the working fluid of the pump, eliminating the differential pressure at the seal part of the penetrating shaft (using a 61! type fluid seal, etc.), preventing leakage, and allowing the use of ordinary bearings. This is an attempt to obtain a highly efficient and leak-free pump.

To explain this with reference to the drawings, in FIG. 1, which is a longitudinal cross-sectional view of the present invention, 1 is a pump body, 2 is an impeller, and 3 is a pump drive shaft. Reference numeral 4 denotes the S-motor main body, which is a pressure vessel that is balanced with the pressure of the pump working fluid and that can withstand the injection hydraulic pressure. 5 is a stator core of an electric motor (usually an AC induction motor), and 6 is a stator winding. 7 is a rotor.

This rotor 7 rotates in lubricating oil, so
Ordinary bearings will suffice and there will be no problem.

Furthermore, since the oil has insulating properties, it has no adverse effect on the stator windings 6, and cooling is better than air cooling. 8.9 is a bearing, and H? due to sealing oil. Because I will be
Ordinary bearings are used, no special Vj such as a canned pump is required, and therefore there are no troubles. 10
is a terminal for taking out the stator winding 6, and is a portion that penetrates the conductor in an airtight manner against hydraulic pressure. Reference numeral 11 is a pressure balancer which balances the hydraulic pressure and the working fluid pressure of the pump. Reference numeral 12 is a pressure balance bellows, which may be a piston or a diaphragm depending on the case.

Reference numeral 13 is a nozzle holder that guides the hydraulic pressure of the shaft seal.

Reference numeral 14 indicates piping for the working fluid pressure of the pump. 15 is a seal that separates the working fluid and sealing oil. This uses a magnetic fluid seal for high temperature and high pressure, and a regular oil seal for low temperature and low pressure. Reference numeral 16 denotes a cooling water passage that cools the shaft portion when the working fluid of the pump is at a high temperature.

[Brief explanation of drawings]

FIG. 1 shows a longitudinal cross-sectional view of the invention.

Claims (1)

[Claims] A leak-free pump that prevents leaks for 1 hour by immersing the inside of the motor in oil with the same pressure as the pump working fluid to eliminate differential pressure at the penetrating shaft.