GB2290352A - Pumps - Google Patents

Abstract

In a pump, e.g. a drum pump, having a piston movable in a cylinder, the piston 24 has apertures 41 with peripheries 42, 42a which at least in part are non-axial, converging in the direction of delivery flow. Flow through the piston apertures is controlled by a disc valve 26. <IMAGE>

Description

PUMPS This invention relates to pumps.

The invention is concerned with improvements in pumps, for example the type of pump known as a drum pump. Such pumps have mainly been used for the discharge of petroleum products from drums either to a hose or to a free-standing vessel.

According to this invention a pump comprises a piston movable in a cylinder, the piston including aperture means, at least a part of the periphery of the aperture means being non-axial.

All the periphery may be non-axial. The periphery may converge as it extends in the delivery direction of liquid flow.

The invention also provides a piston for a pump, the piston having aperture means, at least a part of a periphery of the aperture means being non-axial.

The invention may be performed in various ways and one specific embodiment of the invention with possible modifications will now be described by way of example with reference to the accompanying drawings, in which: Fig. 1 is a perspective view of a drum pump; Fig. 2 is an axial underside view of a piston; Fig. 3 is a section on the line 3-3 of Fig. 2; Fig. 4 is an axial plan view of a modified piston; Fig. 5 is a section on the line 5-5 of Fig. 4; and Fig. 6 is a section on the line 6-6 of Fig. 4.

The pump shown has a modular nylon glass filled body 10 with an integral base 11 and a top 12 which can be screw-on or, as shown, a bayonet connection with body 10. An integral boss 13 exists at the base of the body 10 and a telescopic suction tube 14 is shown attached to an internal boss 15. The boss 13 can have two threaded portions to allow for fitting of the pump into Imperial or Metric apertures. The top 12 has an outlet neck 18 with a bayonet peg 19 and a discharge pipe 21 is shown fitted in the neck so that it extends upwardly from the body 10. The pipe 21 has a discharge nozzle 22 pointing downwardly. The substantially cylindrical inner surface 10a of body 10 has a slight internal taper so as to be wider at the top e.g. a taper of 0.15 mm.A piston 24 is made of an inert "Nylon" material and it has a feather edge 25 extending upwards designed to move to fit the cylinder bore exactly in all positions of axial movement of the piston. The piston is substantially rigid but the edge is capable of accommodating the internal taper of the body whilst providing a self-priming action. Mounted on the piston and above it, in well known manner, there is a clack valve or secondary self priming self cleaning disc 26. A bottom clack valve disc or priming check valve disc 27 is trapped loosely in a cavity by suitable means which is peened at the rim of the cavity. The cylinder part of the body 10 can have a textured outer finish to provide a non-slip grip surface for mounting the pump in a barrel by hand without the use of tools.The piston 24 is reciprocable by means of a rod 31 movable in a seal 32 and guided by a bearing in a skirt depending from the lid 12. The rod 31 is pin-jointed to a handle 34 which can pivot about a pin on a rod carried on a bracket pair, (not shown).

The bearing provides a large bearing surface and avoids concentration of stresses in the top 12.

The handle is operated to reciprocate the piston in the cylinder to effect pumping.

As can be seen from Figs. 2, 3 the piston 24 has a central aperture 40 for connected receipt of rod 31 and a plurality of apertures, as shown four apertures 41, which in the present case have boundary edges 42, 42a which are non-axial. As shown they converge upwardly from the lower end face 43. The curved boundary edges 42a, in a modification, may remain axial.

Formation of one or more or all of the edges 42, 42a as non-axial produces less turbulence in the liquid being pumped and serves to speed up the pumping action and improves the priming action.

As shown as a top plan view in Fig. 4, there could be more than four, e.g. six apertures 41. In Figs. 4 to 6, the clack disc 26 in one operating position engages surface 50; ribs 51 are tapered.

The described pump is a multi-functional hand-operated pump which can be hand-held or screwed into a drum or fixed into a wall or other fitting with supply and delivery hoses. The piston design enables the pump to operate with various liquids of a wide range of viscosity e.g. water, edible liquids, lubricants, chemicals.

Claims (6)

1. A pump comprising a piston movable in a cylinder, the piston including aperture means, at least a part of the periphery of the aperture means being non-axial.

2. A pump comprising a piston movable in a cylinder, the piston including aperture means, at least a part of the periphery of the aperture means being non-axial, and a valve member co-operable with the piston for closing the aperture means in one direction of movement.

3. A pump as claimed in Claim 1 or Claim 2, in which all the periphery is non-axial.

4. A pump as claimed in Claim 1 or Claim 2 or Claim 3, in which the periphery converges as it extends in a delivery direction of liquid flow.

5. A pump substantially as hereinbefore described with reference to and as shown in Figs. 2 and 3, or Figs. 4 to 6, of the accompanying drawings.

6. A piston for a pump, the piston having aperture means, at least a part of the periphery of the aperture means being nonaxial.