WO2014040125A1

WO2014040125A1 - Pump for abrasives

Info

Publication number: WO2014040125A1
Application number: PCT/AU2013/001033
Authority: WO
Inventors: Darren John REUKERS
Original assignee: Techni Waterjet Pty Ltd
Priority date: 2012-09-11
Filing date: 2013-09-11
Publication date: 2014-03-20

Abstract

A pump for the delivery of particulate material, the pump comprising a storage chamber having a top and a bottom arranged to contain particulate material, the chamber having an outlet port and an inlet aperture, the chamber having an air inlet to facilitate entry of compressed air that in use forces the particulate material out of the outlet port, the pump having a valve upstream of the inlet aperture to control flow of particulate material into the chamber, the valve comprising a valve member within a valve chamber fed by a source of compressed air whereby pressurisation of the valve chamber displaces the valve member to close the valve and cause a seal.

Description

PUMP FOR ABRASIVES

This invention relates to a pump for abrasives especially for use with a water et cutting machine.

Background

Waterjet cutting machines use an abrasive material, typically garnet, which is mixed with ultra high pressure water to create an erosion process used to cut a variety of materials including steel, glass or stone.

It is usual for the abrasive to be stored in a large pressure vessel ranging between 100 to 1000kg. The pressure vessel feeds the abrasive under pressure through a hose to a small delivery/metering hopper which is mounted close to the cutting head of the waterjet cutting machine . The abrasive is delivered to the pressure vessels in large transport bags. The pressure vessel has to be de- pressurised and then opened to allow the abrasive to be poured from the bags into the pressure vessel. The pressure vessel then has to be re-pressurised to deliver the abrasive to the delivery/metering hopper. This is a slow process which can result in the addition of

impurities into the abrasive which can cause blocking of the cutting head. Large pressure vessels are also very expensive to manufacture and require certification.

It is these issues that have brought about the present invention .

Summary

In accordance with the present invention there is provided a pump for the delivery of particulate material, the pump comprising a storage chamber having a top and a bottom arranged to contain particulate material, the chamber having an outlet port and an inlet aperture, the chamber having an air inlet to facilitate entry of compressed air that in use forces the particulate material out of the outlet port, the pump having a valve upstream of the inlet aperture to control flow of particulate material into the chamber, the valve comprising a valve member within a valve chamber fed by a source of compressed air whereby pressurisation of the valve chamber displaces the valve member to close the valve and cause a seal.

Brief Description of the Drawings

An embodiment of the present invention will now be

described by way of example only with reference to the accompanying drawings in which:

Figure 1 is a perspective view of a frame for delivering abrasive from a transport bag to a hopper, the base of the hopper being secured to a pump in accordance with one embodiment of the invention;

Figure 2 is a cross-sectional view of the pump with a valve open; and

Figure 3 is a cross-sectional view of the pump with the valve closed.

Detailed Description

In the embodiment illustrated in Figures 1 to 3, a pump 10 is designed for use in transferring abrasive usually in the form of garnet to the cutting head of a water et cutting machine (not shown) .

As shown in Figure 1, the pump 10 is located directly below a tapered hopper 11 that is located centrally in the open mouth 12 of a rectangular table 15 fabricated in square steel sections. An L shaped hanging frame 20 extends from one end of the table 15 to have a bar 21 that extends across the table 15 at a position elevated above the table 15. The bar 21 has suspended therefrom a bulk abrasive transfer bag B that is designed to have a

capacity of between 1 and 2 tonnes of abrasive. The bag B has a cylindrical delivery chute 25 on its underside and an open top 26 and is suspended by straps 28 attached to a cross frame 27 which is in turn secured to the hanging frame 20. The delivery chute 25 of the bulk abrasive bag B extends into the open mouth of the hopper 11 and, in use, the abrasive flows under gravity, out of the bag B down into the hopper 11 to fill the hopper 11. Once the hopper 11 is full, the abrasive stacks up through the chute 25 into the hopper 11 and no further release of abrasive takes place until the hopper 11 is opened.

Release of the abrasive from the hopper 11 is controlled by the pump 10, details of which are shown in Figures 2 and 3. The pump 10 comprises a cylindrical storage chamber 50 with base 51 including an abrasive out feed port 52 that is coupled to a delivery tube 53 that directs the abrasive to the delivery/metering hopper at the cutting head (not shown) . The top of the chamber 50 supports an upper flange 55 with a central delivery aperture 56. At one side of the flange 55 is an air inlet aperture 57 which is connected to a source of compressed air so the chamber can be pressurised to a pressure approximately 40psi. A valve 60 includes a valve member in the form of rubber or plastics boot 61 with a central throughway 69 having circular end flanges 62 and 63 located within a valve housing 64 that is in turn sealed at the upper end by an adaptor panel 65. The lower end of the rubber boot 61 is secured to the valve housing 64 by an annular plate 66. The valve housing 64 defines a valve chamber 68 with the valve member 61 and the valve housing 64 has an air inlet aperture 70 which is adapted to receive compressed air at a pressure of about lOOpsi. The air pressure through the valve chamber 68 and the abrasive storage chamber 50 is controlled through a regulator (not shown) .

The pump 10 is secured to the underside of the hopper 11 so that the abrasive can flow through the central

throughway 69 of the valve 60 and into the abrasive storage chamber 50. Figure 2 shows the valve 60 in an open configuration in which there is no pressure

difference between the central throughway 69 of the valve 60 and the valve chamber 68. A lower level sensor 58 is positioned adjacent the base 51 of the chamber 50 and an upper level sensor 59 is positioned near the upper flange 55. The sensors 58, 59 could be inductive sensors or operate on electric eye principle to simply monitor the level of abrasive within the chamber 50.

To close the valve 60 compressed air at lOOpsi is passed into the valve housing 64 which pressurises the chamber 68 to cause the rubber boot 61 to distort to the position shown in Figure 3 in which the central throughway 69 is closed. The closed configuration abrasive cannot drop into the hopper 11. The upper level sensor 59 and the lower level sensor 58 ensure that the valve 60 is opened and closed as necessary to keep the abrasive chamber full of abrasive material.

When the pump 10 is full of abrasive, the upper level sensor 59 is triggered to actuate the valve 60 to direct air around the rubber boot 61 causing it to collapse on the abrasive flow causing a seal. At the same time air is directed into the pump 10 via the regulator (not shown) to reduce the pressure. The pump 10 becomes pressurised and forces the abrasive through the hose delivery/metering hopper 11. When the abrasive reaches the lower limit sensor, the valve 60 closes and the pump 10 is de- pressurised. The rubber boot 61 opens and allows abrasive to flow into the pump 10. The cycle then continues.

The pump 10 described above is a simple and reliable unit that provides regular delivery of abrasive or garnet to a water et cutting machine without the need for the very large complex and certified abrasive storage pressure chamber . In the claims which follow and in the preceding

description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

Claims

Claims :

1. A pump for the delivery of particulate material, the pump comprising a storage chamber having a top and a bottom arranged to contain particulate material, the chamber having an outlet port and an inlet aperture, the chamber having an air inlet to facilitate entry of compressed air that in use forces the particulate material out of the outlet port, the pump having a valve upstream of the inlet aperture to control flow of particulate material into the chamber, the valve comprising a valve member within a valve chamber fed by a source of

compressed air whereby pressurisation of the valve chamber displaces the valve member to close the valve and cause a seal .

2. The pump according to claim 1 wherein, the storage chamber has sensors adjacent the top and bottom to detect the presence of particulate material.

3. The pump according to either claim 1 or 2, wherein a regulator controls the pressure of the compressed air entering the storage chamber and valve chamber.

4. The pump according to any one of the preceding claims, wherein the valve member is a flexible sleeve with a central throughway located in the valve member whereby pressurisation of the valve chamber causes the sleeve to flex to close the throughway thereby closing the valve.

5. The pump according to claim 4, wherein the flexible sleeve has flanges at the top and bottom that are secured to a valve housing.

6. The pump according to any one of the preceding claims wherein the pump is used to deliver abrasive to the cutting head of a water et cutting machine.