Geared positive-displacement pump with self-compensating gear chamber

Abstract

A positive-displacement pump ( 10 ) of the type comprising a driving gear ( 12 ) and a driven gear ( 14 ) perfectly coupled together and each mounted on a respective support shaft ( 16, 18 ). The driving gear ( 12 ) is operatively connected to a motor ( 20 ) to set the driven gear ( 14 ) in rotation and generate the pumping action on a fluid. The gears ( 12, 14 ) are contained in a chamber ( 40 ) provided with a closing plate ( 42 ). The support shafts ( 16, 18 ), the central body ( 38 ) of the pump ( 10 ), the chamber ( 40 ) that contains the gears ( 12, 14 ), the closing plate ( 42 ) of such a chamber ( 40 ), an inner magnet ( 36 ) and the base of the rear body ( 28 ) of the pump ( 10 ) are in turn housed inside a casing ( 30 ) of the pump ( 10 ).

1 . Positive-displacement pump ( 10 ) of the type comprising a driving gear ( 12 ) and a driven gear ( 14 ) perfectly coupled together and each mounted on a respective support shaft ( 16 ,  18 ), the driving gear ( 12 ) being operatively connected to a motor ( 20 ) to set the driven gear ( 14 ) in rotation and generate the pumping action on a fluid, said gears ( 12 ,  14 ) being contained in a chamber ( 40 ) provided with a closing plate ( 42 ), the support shafts ( 16 ,  18 ), the central body ( 38 ) of the pump ( 10 ), the chamber ( 40 ) that contains said gears ( 12 ,  14 ), the closing plate ( 42 ) of said chamber ( 40 ), an inner magnet ( 36 ) and the base of the rear body ( 28 ) of the pump ( 10 ) in turn being housed inside a casing ( 30 ) of the pump ( 10 ), characterised in that said chamber ( 40 ) and the relative closing plate ( 42 ) are mounted in a mobile manner with respect to one another and both with respect to other components of the pump ( 10 ) as a function of the pressure of the fluid contained in said pump ( 10 ), so as to allow the adaptability of said chamber ( 40 ) and of the relative closing plate ( 42 ) as the clearances vary due to the wearing of the internal components of the pump ( 10 ) that are moving, or that are in contact with other moving components. 
     
     
         2 . Positive-displacement pump ( 10 ) according to  claim 1 , characterised in that between the support base ( 38 A) of the central body ( 38 ) and the support edge ( 40 A) of the chamber ( 40 ) at least one elastic component ( 50 ) is interposed, that allows the relative displacement, with respect to said central body ( 38 ), of said chamber ( 40 ) as a function of the pressure of the fluid contained in it. 
     
     
         3 . Positive-displacement pump ( 10 ) according to  claim 2 , characterised in that said at least one elastic component ( 50 ) consists of an O-ring. 
     
     
         4 . Positive-displacement pump ( 10 ) according to  claim 1 , characterised in that between the chamber ( 40 ) and the base of the rear body ( 28 ) there is, in non-operative conditions of the pump ( 10 ), a space (D) to allow said chamber ( 40 ) to be brought towards and away from said base of the rear body ( 28 ) as a function of the pressure of the fluid. 
     
     
         5 . Positive-displacement pump ( 10 ) according to  claim 4 , characterised in that between the outer surfaces of the gears ( 12 ,  14 ) and the inner surfaces of the chamber ( 40 ) and of the relative closing plate ( 42 ) there are clearances (P, T, V) that can vary based on the pressure of the fluid contained in the gaps (M, R) formed between the inner magnet ( 36 ), the central body ( 38 ) and said chamber ( 40 ). 
     
     
         6 . Positive-displacement pump ( 10 ) according to  claim 5 , characterised in that the elastic component ( 50 ) is configured to push the chamber ( 40 ) towards the rear body ( 28 ) as a function of the pressure of the fluid contained in said gaps (M, R), contributing to decreasing at least part of said clearances (T, V) and said space (D), the pressure of the fluid contained in said gaps (M, R) also causing the displacement of the closing plate ( 42 ) inside said chamber ( 40 ) and the approach of said chamber ( 40 ) to the side surface of the gears ( 12 ,  14 ). 
     
     
         7 . Positive-displacement pump ( 10 ) according to  claim 1 , characterised in that the motor ( 20 ) is able to transmit the rotary motion to an external magnet ( 52 ) that in turn transmits the motion to the inner magnet ( 36 ) through magnetic drive. 
     
     
         8 . Positive-displacement pump ( 10 ) according to  claim 7 , characterised in that the inner magnet ( 36 ) is equipped with a recess ( 54 ) suitable for the insertion inside it, in shape coupling, of a protuberance ( 56 ) formed in the driving gear ( 12 ), so that the motion generated by the motor ( 20 ) is transmitted directly to said driving gear ( 12 ) 
     
     
         9 . Positive-displacement pump ( 10 ) according to  claim 8 , characterised in that the support shafts ( 16 ,  18 ) of the gears ( 12 ,  14 ) are fixed, because they are planted in respective seats ( 58 A,  58 B) of the rear body ( 28 ), in this way making the use of bushings superfluous.