Plunger-type measuring pump

Abstract

A plunger-type measuring pump in which a pump head 9 can be correctly attached to a pump body 1 with a reduced amount of time and labor is provided. The plunger-type measuring pump according to the present invention includes: a pump body 1 supporting a plunger 2 while allowing a reciprocating motion of the plunger 2; a cylindrical head-attachment portion 82 provided at one end of the pump body 1, the head-attachment portion 82 having a male-thread portion 83 formed on an outer circumference thereof; a pump head 9 having a pump chamber 91 inside, the pump head 9 being designed to be attached to the head-attachment portion 82 with a seal 4 therebetween; and a sleeve-like fixing part 7 to be fitted onto the outer circumference of the pump head 9, the sleeve-like fixing part 7 having an inner circumferential wall on which an engaging portion 74 to be engaged with the pump head 9 and a female-thread portion 72 to be screwed onto the male-thread portion 83 are formed. Since a single sleeve-like fixing part 7 is used to fix the pump head 9 to the cylindrical head-attachment portion 82 provided on the pump body 1, it is unnecessary to pay attention to the evenness in the tightening force applied to bolts 6.

1 . A plunger-type measuring pump for sending liquid by reciprocating a plunger in a pump chamber, comprising:
 a pump body for supporting the plunger while allowing a reciprocating motion of the plunger;   a cylindrical head-attachment portion provided at one end of the pump body, the head-attachment portion having a thread portion on an outer circumference thereof;   a pump head having the pump chamber inside, the pump head being designed to be attached to the head-attachment portion with a seal therebetween; and   a sleeve-like fixing part to be fitted onto the outer circumference of the pump head, the sleeve-like fixing part having an inner circumferential wall on which an engaging portion to be engaged with the pump head and a thread portion to be screwed onto the thread portion of the cylindrical head-attachment portion are formed.   
     
     
         2 . The plunger-type measuring pump according to  claim 1 , wherein the pump head has a flange with which the engaging portion is to be engaged. 
     
     
         3 . The plunger-type measuring pump according to  claim 1 , wherein:
 the sleeve-like fixing part has a large-hole section having a large inner diameter and a small-hole section having a small inner diameter; and   the engaging portion is a boundary section between the large-hole section and the small-hole section.   
     
     
         4 . The plunger-type measuring pump according to  claim 2 , wherein:
 the sleeve-like fixing part has a large-hole section having a large inner diameter and a small-hole section having a small inner diameter; and   the engaging portion is a boundary section between the large-hole section and the small-hole section.