AU2006203229A1

AU2006203229A1 - Filter Assembly

Info

Publication number: AU2006203229A1
Application number: AU2006203229A
Authority: AU
Original assignee: Crafers Eng Pty Ltd
Current assignee: CRAFERS ENGINEERING Pty Ltd
Priority date: 2006-07-27
Filing date: 2006-07-27
Publication date: 2008-02-28

Description

P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Invention Title: "IN-LINE FILTER APPARATUS" The following statement is a full description of this invention, including the best method of performing it known to me/us: C FILTER ASSEMBLY This invention relates to a filter assembly especially adapted for use in Cdispensing systems for dispensing flowable material and in particular to hot melt adhesive dispensing systems.

Conventional hot melt adhesive dispensing systems are described in \International Publication WO 03/037591and include a tank, heater, a pump, a pump manifold and a controller which all combine to supplying heated liquid adhesive to one or more dispensing guns and heated hoses in fluid communication with the dispensing gun(s) and the pump manifold.

The heater is usually located in a base of the tank for melting and heating adhesive material received in the tank in solid or semi-solid form.

The pump manifold has an inlet connected to the tank and has multiple outlet ports adapted for connection to the heated hoses. The controller controls the power supplied to the tank heater and heated hoses to maintain the liquid adhesive at an appropriate viscosity and temperature depending on the application.

WO 03/037591 describes a pump containing a removable filterwhich is positioned between an inlet and outlet of the pump to capture particles contained in the adhesive as the adhesive flows through the-pump. The removable filter is described as having a cartridge that is removable from the pump. There is also described a filter where the filter housing or body may be removed from the cartridge such as through a press fit connection so that the cartridge is reusable.

It has been found in practice that a releasble connection between the Sfilter housing and the cartridge by use of a press fit has disadvantages because it requires specialised machinery to separate or connect mating c machinery parts in a press fit relationship and (ii) also requires a skilled operator to operate the machinery. It also requires specialised calculations as described for example in Stamenkovic et al FACTA UNIVERSITATIS I Mechanical Engineering, Vol 1, No 8 2001 pp 1057-1064 to form a press fit that is satisfactory in practice. This reference is discussed in greated detail hereinafter.

It is therefore an object of the invention to provide a filter assembly for use in a hot melt adhesive dispensing system which may at least alleviate the disadvantages of the prior art.

The filter assembly of the invention therefore includes: a filter housing formed of mesh or perforated material having a lower end which has an attachment aperture; (ii) a cartridge engageable with an upper end of the filter housing, and (iii) an elongate fastener which extends through the attachment aperture in the lower end of the filter housing and which engages in a mating bore in the cartridge.

Preferably the elongate fastener has a screw threaded upper end in use which engages with a mating screw threaded bore in the cartridge.

The cartridge is engageable with the upper end of the filter housing and such engagement need only be in abutting relationship and does not require an intimate connection which can be achieved by an interference fit Sor a press fit as described in WO 03/037591.

SReference to a preferred embodiment may be made in the attached drawings wherein: FIG 1 is a schematic view of the filter assembly of the invention in use; and (Ni \FIG 2 is an exploded perspective view of the filter assembly shown in

IND

FIG 1.

In FIG 1 there is shown filter assembly 10 in use and FIG 1 is a schematic version of FIG 2 of International Patent Publication WO 03/037591 which is incorporated herein by reference in its entirety.

As shown in FIG 1, filter assembly 10 is mounted in a pump housing 11 and is located in a filter chamber 12 between inlet passage 13 and outlet passage 14 such that particles contained in liquid adhesive may be captured by the filter assembly 10 prior to exiting a pump (not shown) located above filter assembly 10. In the present embodiment the filter assembly 10 is attached to a cartridge 15 as stated in WO 03/037591 and is removable from the pump housing 11 for cleaning or replacement. Filter cartridge 15 is retained in filter chamber 12 by screwing the cartridge into an adaptor (not shown) using screw threaded part 16 as described in WO 03/037591.

The adhesive flows from inlet passage 13 into an annular passage 17 and into filter assembly 10 through inlet apertures 18. Adhesive then flows through the hollow interior 19 of filter assembly 10 and radially outwardly through perforations 20 in housing 21 into filter chamber 12 and subsequently through outlet passage 14 as shown by the arrows. The c adhesive may then flow into manifold 22 where the flow of adhesive is split and directed to outlet ports 23 which are configured to be coupled to heated choses (not shown) whereby the liquid adhesive is supplied to a pair of adhesive guns (not shown). In a more preferred arrangement there may be provided two pairs of outlet ports 23 as shown in WO 03/037591 but FIG 1 is c- only a schematic and simplified arrangement of the hot melt adhesive system shown in WO 03/037591.

Any particulate material larger than the pore size of perforations 20 is trapped in the hollow interior 19 of filter housing 21. At relevant time intervals, cartridge 15 may be unscrewed from the adaptor (not shown) and filter assembly 10 may be removed for cleaning, maintenance and/or replacement.

In accordance with the invention as shown in FIG 2 there is provided an elongate fastener 25 in the form of a bolt having a head 26 and screw threaded bottom portion 27. Head 26 is provided with a slot 28 for engagement by a screwdriver or other suitable tool (not shown). As shown in FIG 1, screw threaded portion 27 engages with mating screw threaded aperture 29 in cartridge 15 and head 26 abuts base surface 30 of filter assembly 10. Also as shown in FIG 2 head portion 31 of filter housing engages in abutting relationship with abutment or end projection 32 of cartridge 15. Cartridge 15 is also provided with body 33 and nut 34 welded to flange The advantages of using a releasable connection between the filter housing 21 and cartridge 15 in the form of use of an elongate bolt c extending through the hollow interior 19 of filter housing 21 and in screw threaded connection with aperture 29 of cartridge 15 means that the idisconnection between housing 21 and cartridge 15 may be carried out by any unskilled person in minimal time and little effort. This also means that all that head portion 31 needs to be is in abutting relationship with abutment 32.

ciHowever in WO 03/037591 reference is made to a press fit between the filter housing and the cartridge so that the cartridge is reusable. However it will be appreciated that a press fit between mating parts can only be achieved by accurate machinery of the parts so that it is necessary to have precise calculations which involve knowledge of the precise value of the static friction co-efficient to reliably estimate the press fit joint strength. This is pointed out in Stamenkovic et al FACTA UNIVERSITATIS, Mechanical Engineering, Vol 1, No 8, 2001, pp 1057-1064.

Thus if a press fit is used it requires not only the relevant machinery but also a skilled operator to separate the mating parts. This is why the present invention clearly has substantial advantages over the prior art.

Claims

2. A filter assembly as claimed in claim 1 wherein the elongate fastener has a screw threaded upper end in use which engages with a mating screw threaded bore in the cartridge.
3. A filter assembly as claimed in claim 1 wherein the cartridge is engageable with an upper end of the filter housing in use in abutting relationship.
4. A filter assembly as claimed in claim 1 substantially as herein described with reference to the drawings.