Positive-displacement pump and pumping group for fluid products and method for the use thereof

Abstract

A positive-displacement pump for fluid products, in particular paints, colorants and the like, includes a pump body in which there is formed a pumping chamber, in which a piston is mounted for sliding and is controlled so as to advance and withdraw in order to vary the useful volume of the pumping chamber. The pumping chamber has an upper region located at the highest location of the pumping chamber and in the region of which the pumping chamber is placed in communication with at least one intake pipe for a fluid product.

1 .- 20 . (canceled) 
     
     
         21 . A positive-displacement pump for fluid products, the pump comprising a pump body forming a pumping chamber, a piston mounted for sliding movement within the pumping chamber and being controlled for reciprocating movement within the pumping chamber in order to vary a fluid-product receiving volume of the pumping chamber, a pumping pipe leading into an upper region of the pumping chamber and being in fluid communication therewith, the upper region being located at a highest location of the pumping chamber, an intake pipe in fluid communication with the pumping chamber, the intake pipe communicating with a tank containing fluid product and positioned at a greater height with respect to the positive-displacement pump so as to produce a hydraulic head and a fluid travel path with a constant descent from the tank to provide fluid product from the tank to the pumping chamber. 
     
     
         22 . The positive-displacement pump according to  claim 21 , further comprising a valve chamber disposed above the pumping chamber, the intake pipe of the positive-displacement pump being inclined with respect to a horizontal plane from the valve chamber as far as the tank containing the fluid product. 
     
     
         23 . The positive-displacement pump according to  claim 21 , wherein the pumping chamber is elongate in configuration and has a longitudinal axis, the longitudinal axis being inclined with respect to a horizontal plane. 
     
     
         24 . The positive-displacement pump according to  claim 21 , wherein the pumping chamber is elongate in configuration and has a non-vertical longitudinal axis. 
     
     
         25 . The positive-displacement pump according to  claim 21 , wherein the pumping chamber comprises a substantially cylindrical portion with a constricted end, the upper region being positioned near or adjacent the constricted end. 
     
     
         26 . The positive-displacement pump according to  claim 25 , wherein the constricted end is substantially frustoconical, the upper region being positioned substantially near or adjacent a transition between the substantially cylindrical portion and the constricted end. 
     
     
         27 . The positive-displacement pump according to  claim 21 , further including a discharge pipe for discharging the fluid product and a head body mounted on the pump body, the intake pipe and the discharge pipe being formed so as to be located in, and formed integrally with, the head body. 
     
     
         28 . The positive-displacement pump according to  claim 21 , further comprising a head body mounted on the pump body and an interception member provided on the intake pipe, the interception member being mounted on the head body. 
     
     
         29 . The positive-displacement pump according to  claim 21 , further comprising a discharge pipe disposed to discharge the fluid product, a head body mounted on the pump body and an interception member provided on the discharge pipe, the interception member being mounted on the head body. 
     
     
         30 . The positive-displacement pump according to  claim 21 , further including a discharge pipe disposed to discharge the fluid product and a three-way valve, the pumping chamber communicating with the three-way valve, the three-way valve being actuable for selective communication with the intake pipe and the discharge pipe. 
     
     
         31 . The positive-displacement pump according to  claim 30 , wherein the three-way valve comprises a valve chamber arranged above the pumping chamber, the intake pipe being inclined upwards with respect to a horizontal plane from the valve chamber. 
     
     
         32 . The positive-displacement pump according to  claim 21 , wherein the piston includes an outer skirt in the form of a bellows. 
     
     
         33 . The positive-displacement pump according to  claim 21 , further including a discharge pipe for discharging the fluid product, the pumping pipe comprising a single pumping pipe extending from the pumping chamber, the single pumping pipe communicating with the intake pipe and the discharge pipe, the single pumping pipe leading into the pumping chamber at the upper region thereof. 
     
     
         34 . The positive-displacement pump according to  claim 21 , wherein the positive-displacement pump further includes an adapter mounted inside the pumping chamber to reduce the product-receiving volume thereof and therefore reduce a capacity of the positive-displacement pump. 
     
     
         35 . The positive-displacement pump according to  claim 34 , wherein the pumping chamber comprises a substantially cylindrical portion with a constricted end, the adapter comprising a cylindrical portion and a constricted end, a geometry and external dimensions of the adapter corresponding substantially to a geometry and internal dimensions of the pumping chamber such that the adapter covers internal walls of the pumping chamber in order to reduce the product-receiving volume of the pumping chamber. 
     
     
         36 . A method for using a positive-displacement pump according to  claim 21 , the intake pipe being connected to the tank of fluid product, the pump comprising a discharge pipe and interception members which can be selectively controlled in order to open and close the intake pipe and the discharge pipe, the method comprising the steps of:
 controlling the interception members in order to open the intake pipe and to close the discharge pipe;   controlling the piston so as to withdraw in order to transfer a quantity of fluid product from the tank to the pumping chamber;   controlling the piston so as to advance and keeping the intake pipe open and the discharge pipe closed;   opening the discharge pipe and closing the intake pipe during the advance movement of the piston in order to discharge a quantity of fluid product.   
     
     
         37 . The positive-displacement pump according to  claim 21 , wherein the intake pipe is in fluid communication with the pumping chamber via the pumping pipe. 
     
     
         38 . A positive-displacement pump for fluid products, said pump comprising:
 a pump body forming a pumping chamber, the pumping chamber having a summit zone which includes the highest location of the pumping chamber and an opening disposed adjacent and in fluid communication with the summit zone;   a pumping pipe leading into the opening of the pumping chamber;   an intake pipe disposed to receive a fluid product from a tank positioned at a greater height than the pump to produce a hydraulic head, the intake pipe being in fluid communication with the pumping pipe to provide the fluid product from the tank thereto, the intake pipe defining a fluid travel path for the fluid product which descends from the tank; and   a piston slidably mounted in the pumping chamber, the piston being control.