Lance pump with a ram

摘要

An improved lance pump is disclosed for pumping a pumpable product, particularly lubricant including grease, from a lubricant supply. The pump comprises a head for placement above the supply, a tubular lance structure affixed to the head and extending down into the supply, and a pump tube inside the lance structure that is reciprocated up and down for pumping lubricant from the supply on both upstrokes and downstrokes of the tube. A ram at a lower end of the lance structure is positioned for forcing lubricant up into the tube and past an inlet check valve on a downstroke of the tube.

主权项

1. A lance pump for pumping a pumpable product from a supply thereof, said pump comprising:
a head adapted for placement above said supply; an elongate member constituting a plunger extending down from the head having an upper end and a lower end; said plunger being fixed at its upper end with respect to the head; an elongate tube surrounding the plunger extending down from adjacent the upper end of the plunger to and below the lower end of the plunger and reciprocable up and down through a pump stroke relative to the plunger; a motor-driven mechanism associated with the head for reciprocating the tube through said pump stroke between a raised position relative to the plunger and a lowered position relative to the plunger; said tube having an upper end closure slidable up and down on an upper portion of the plunger; said tube having a lower end closure slidable up and down on a lower portion of the plunger; an elongate annular pump chamber between the plunger and the tube; said tube having an inlet check valve adjacent an open lower end of the tube and below a lower end of the plunger defining in conjunction with the lower end of the plunger an expansible and contractible lower end chamber; the inlet check valve opening on a downstroke of the tube for entry of the pumpable product to said lower end chamber; said plunger having a first passage for outflow of pumpable product from said elongate annular pump chamber to and through an outlet in the head on a downstroke and also on an upstroke of the tube; said plunger having a second passage with a check valve therein adapted to open on each upstroke of the tube with the inlet check valve closed for delivery of pumpable product from said lower end chamber to said elongate annular pump chamber; a tubular lance structure affixed to the head and surrounding the tube; and a ram attached to a lower end of the lance structure, said ram being positioned and oriented to enter into the open lower end of the tube on each downstroke of the tube to force lubricant up into the tube past said inlet check valve and to withdraw from the open lower end of the tube on each upstroke of the tube.