Pump for dispensing a liquid

Abstract

A pump comprises: a plurality of pistons each of which is slidable inside a cylinder so as to vary volume of a corresponding chamber, a plurality of suction valves, each of which is associated with a chamber and is operable to allow a liquid to enter the chamber, the suction valves being arranged in a first sequence, a plurality of delivery valves, each of which is associated with a chamber and is operable to allow said liquid to exit from the chamber, the delivery valves being arranged in a second sequence, an adjusting valve for adjusting pressure of the liquid exiting from the pump. The adjusting valve is interposed between two consecutive valves of a sequence chosen from said first sequence and said second sequence. The pump further comprises: an outlet conduit arranged downstream of the delivery valves, a shutter device interposed between an initial portion of the outlet conduit and a final portion of the outlet conduit, so as to put the initial portion in fluid communication with the final portion, or alternatively separate the initial portion from the final portion, a connecting hole for connecting a portion of the outlet conduit arranged downstream of the shutter device with the adjusting valve.

1 . A pump comprising:
 a plurality of pistons each of which is slidable inside a cylinder for varying volume of a corresponding chamber,   a plurality of suction valves, each of which is associated with a chamber and is operable to allow a liquid to enter the chamber, the suction valves being arranged in a first sequence,   a plurality of delivery valves, each of which is associated with a chamber and is operable to allow said liquid to flow out of the chamber, the delivery valves being arranged in a second sequence,   an adjusting valve for adjusting pressure of the liquid exiting from the pump,   
       wherein the adjusting valve is interposed between two consecutive valves of a sequence chosen between said first sequence and said second sequence, the pump further comprising:
 an outlet conduit arranged downstream of the delivery valves, 
 a shutter device interposed between an initial portion of the outlet conduit and a final portion of the outlet conduit, so as to put the initial portion in fluid communication with the final portion, or alternatively separate the initial portion from the final portion, 
 a connecting hole for connecting a portion of the outlet conduit arranged downstream of the shutter device with the adjusting valve. 
 
     
     
         2 . A pump according to  claim 1 , wherein the adjusting valve is interposed between two consecutive delivery valves of said second sequence. 
     
     
         3 . A pump according to  claim 1 , wherein the suction valves extend along respective axes, the adjusting valve extending along an axis which is oblique with respect to the axes of the suction valves. 
     
     
         4 . A pump according to  claim 3 , wherein the axes along which the suction valves extend are mutually parallel. 
     
     
         5 . A pump according to  claim 1 , wherein the adjusting valve is configured to selectively put a delivery of the pump in fluid communication with a suction of the pump, so that a quantity of liquid can be recirculated from the delivery to the suction in order to vary flow rate of the liquid exiting from the pump, 
     
     
         6 . A pump according to  claim 5 , wherein the adjusting valve comprises a shutter at least partially positioned in a housing, the pump further comprising a connecting conduit which connects the housing to the delivery of the pump, the shutter being configured to isolate or alternately connect the housing with a communication conduit, the communication conduit being in fluid communication with the suction of the pump, 
     
     
         7 . A pump according to  claim 6 , wherein the connecting conduit connects the housing with a delivery valve of said plurality of delivery valves, the communication conduit selectively connecting the housing with an outlet manifold, the outlet manifold being configured to send the liquid to the suction valves. 
     
     
         8 . A pump according to  claim 6 , wherein the shutter has a position inside the housing, said position being determinable as a function of the liquid pressure inside the housing and of a force exerted by a spring on the shutter, the adjusting valve further comprising a control element operable by a user to adjust the force exerted by said spring, 
     
     
         9 . A pump according to  claim 1 , wherein said outlet conduit has a narrowing of its cross-section. 
     
     
         10 . A pump according to  claim 9 , and further comprising an adding device facing said narrowing, the adding device being openable by virtue of a suction action generated by a flow of liquid passing through the outlet conduit, so that the adding device introduces an additive into said flow of liquid.