AU736969B2

AU736969B2 - Low volume puffer stem

Info

Publication number: AU736969B2
Application number: AU55422/98A
Authority: AU
Inventors: John McCarron
Original assignee: AMALGAMATED PEST CONTROL Pty L
Current assignee: AMALGAMATED PEST CONTROL Pty Ltd
Priority date: 1998-02-23
Filing date: 1998-02-23
Publication date: 2001-08-09
Anticipated expiration: 2018-02-23
Also published as: AU5542298A

Description

7- 6, P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT

S

a. Invention Title: "LOW VOLUME PUFFER STEM" The following statement is a full description of this invention, including the best method of performing it known to me/us: "LOW VOLUME PUFFER STEM" FIELD OF THE INVENTION THIS INVENTION relates to a low volume puffer stem for delivering insecticidal dust formations and other materials. In particular, the invention relates to a stem for use with a hand puffer.

BACKGROUND TO THE INVENTION 10 It is known to use insecticidal dust to treat areas against insect infestation. Typically, the dust is delivered to an area by a skilled tradesman who directs the dust into locations which have a high probability of insect activity, such as inside cupboards, under floors o• and in roof spaces.

•:15 The most common method of delivering dust is to fill a hand puffer with the dust and deliver the dust through a hollow stem connected to the puffer. A typical puffer is a generally elongate, resiliently deformable bulb having an open mouth at one end. A hollow stem is removably sealed to the open mouth for dispensing of the dust. Compression of the puffer dispenses the dust through the stem.

It has been known to produce a puffer stem from brass tube.

The prior art puffer stem comprises a double ended inlet tube that is positioned within the puffer bulb and outlet tube which extends through a plug that is fitted into the mouth of the puffer. The inlet tube is bonded to the outlet tube and a port is formed between the tubes for passage of the dust. Compression of the puffer forces dust into the inlet tube which passes to the outlet tube and is delivered to the desired area.

The brass puffer stems suffer from a number of deficiencies including difficulty of manufacture. Accurately sized inlet and outlet holes are essential for controlled delivery of powder but this can be Sodifficult to achieve and maintain with the brass tubes. Furthermore, the brass corrodes, which can erode the inlet and outlet holes making o• them larger. The corrosion can also result in blocking of the holes or the tubes.

OBJECT OF THE INVENTION It is an object of the present invention to provide a low volume puffer stem which overcomes one or more of the identified deficiencies in the known prior art. Further objects will be evident from the following description.

4 DISCLOSURE OF THE INVENTION In one form, although it need not be the only or indeed the broadest form, the invention resides in a low volume puffer stem comprising: an inlet tube having a first inlet end and second inlet end; an outlet tube communicating with said inlet tube, said outlet tube being open at one end; communication means between said inlet tube and said outlet tube for allowing passage of material from said inlet tube to said outlet :10 tube; and entry restriction means removably located on each end of said S•inlet tube; wherein said puffer stem is formed from tubular plastics **.material.

S"BRIEF DETAILS OF THE DRAWINGS To assist in understanding the invention, preferred embodiments will now be described with reference to the following figures in which: FIG. 1 is a sketch of a low volume puffer stem; FIG. 2 is a side view of the low volume puffer stem of FIG. 1 showing the dust flow path; FIG. 3 is a cut-away view of the low volume puffer stem of FIG.

1 in combination with a hand puffer; and FIG. 4 shows the hand puffer and low volume puffer stem of FIG. 3 in an inverted position.

DETAILED DESCRIPTION OF THE DRAWINGS In the drawings, like reference numerals refer to like parts.

Referring to FIG. 1, there is shown a low volume puffer stem, generally indicated at 1. The low volume puffer stem comprises a S" plastic inlet tube 2 with a small hole 3 formed intermediate its ends 4 and 5. The inlet tube 2 is bonded to outlet tube 6 using hot melt glue 7 and shrink wrap 8. An aperture 9 is formed in the outlet tube 6 approximal one end. The hole 3 in the inlet tube 2 is aligned with the aperture 9 in the outlet tube 6 to allow passage of dust from the inlet tube to the outlet tube.

Alignment of the apertures is conveniently achieved by applying ~15 the hot melt glue 7 and shrink wrap 8 to the tubes to assemble the first stage of the low volume puffer stem. Once the two tubes are positioned and bonded together, a hole may be drilled through both tubes. This process leaves undesired holes in the walls of the inlet tube and outlet tube opposite the points of communication between the tubes. A sheath 10 is positioned over the joined tubes to block the undesired outer holes. The sheath 10 may conveniently be shrink wrap material.

Alternately, the apertures 3 and 9 may be formed in the tubes prior to assembly. In this case, careful attention must be given to achieving alignment of the apertures 3 and 9.

It would also be suitable to bevel and flare one end of the outlet tube so that it covered a hole made in the inlet tube. The tubes could then be joined such that the hole in the inlet tube communicated directly with the flared and bevelled end of the outlet tube. This arrangement requires more processing than the aforementioned arrangements and is therefore not preferred.

In order to obtain an appropriate flow through the low volume puffer stem, it is desirable to restrict the inlet diameter to approximately 1mm. In the prior art, this has been achieved by drawing down the inlet tube however accurate formation of an inlet restriction is problematic with this approach. Furthermore, if any 15 blockage occurs cleaning is extremely difficult. The inventor has found that there is great advantage in providing a ferrel 11 on each end of the inlet tube 2. The ferrule 11 has an internal diameter approximately of the same size as the external diameter of the inlet tube so that the ferrel will be frictionally retained on the inlet tube but with the application of moderate force may be removed. The ferrule 11 is closed at one end but for an aperture 12 of the desired diameter.

The aperture 12 restricts the flow of dust into the low volume puffer stem. In the event that the inlet tube 2 becomes blocked, the ferrule 11 can be removed and the blockage easily cleared.

The inlet tube 2 is formed from resiliently deformable plastics material which allows the inlet tube 2 to be bent away from the outlet tube 6 to facilitate positioning of the ferrule 11 on the end of the inlet tube which is adjacent to the outlet tube 6. It will be appreciated that the prior art puffer stems formed from brass tubes do not allow this deflection and it is therefore not possible to apply ferrules as in the present invention. This makes the restriction of flow and cleaning of 0. 0.

the inlet tubes of the prior art, quite difficult.

The outlet tube 6 may have a reduced diameter at the outlet end 13. This reduced diameter can be achieved by inserting a smaller diameter tube 14 into the outlet tube 6. The smaller diameter tube 14 may be fixed in the outlet tube 6 using an adhesive or alternatively may be retained by frictional fit. Frictional engagement allows the 15 reduced diameter tube 14 to be removed from the outlet tube 6 to S"facilitate easy cleaning of the outlet tube 6, should it become blocked.

The flow of dust through the low volume puffer stem is shown most clearly in FIG. 2. Dust flows in through inlets 12 as indicated by arrows 15. The dust passes through the communicating port 3, 9 as indicated by arrows 16. The dust is then dispensed through the end of the outlet tube 6 and reduced diameter tube 14 as indicated by arrows 17.

8 The method of use of the low volume puffer stem is shown in FIG's. 3 and 4. The low volume puffer stem 1 is used in conjunction with a hand puffer 18. The hand puffer 18 is a resiliently deformable bulb having a mouth at one end. The mouth is blocked by a plug 19 which suitably screws into the mouth of the puffer 18. A bore 20 is formed in the plug 19 to receive the outlet tube 6 of the puffer stem.

The bore 20 is just smaller than the outside diameter of the outlet tube 6 so that the outlet tube 6 makes an interference fit in the bore 20. If desired, the outlet tube 6 may be fixed in the bore 20 with suitable :o 10 adhesive.

As shown clearly by FIG's. 3 and 4, powder 21 in puffer bulb 18 will settle at the lowest point of the puffer bulb. When the hand puffer is being held upright, the dust is drawn through one inlet as shown in FIG. 3. When inverted, the dust is drawn through the other inlet as shown in FIG. 4.

To manufacture the low volume puffer stem of FIG. 1, a length of appropriate diameter tube is cut to form the inlet tube 2. A slightly larger diameter tube is cut to an appropriate length to form the outlet tube 6. The inlet tube 2 and outlet tube 6 are positioned so that one end of the outlet tube is adjacent the middle of the inlet tube. Hot melt glue is forced into the end of the outlet tube and around the adjacent inlet tube. A piece of shrink wrap is then placed over the central region of the inlet tube and the end of the outlet tube. Heat is 9 applied to set the hot melt glue and shrink the shrink wrap thereby holding the tubes in position with the end of the outlet tube being completely blocked.

A small diameter drill is used to bore a hole through the inlet tube and the outlet tube. Any waste material which falls inside the tubes is blown or tapped out of the tubes. An appropriately diameter tube is forced over the inlet and outlet tubes to cover the hole formed e• in the previous step. This sheath can be glued in place if desired or shrunk using heat.

10 Ferrule 11 are manufactured with internal diameter to match the outside diameter of the inlet tube and appropriate sized aperture formed in the closed end. The inlet and outlet tubes are spread apart to allow positioning of the ferrule on one end of the inlet tube and •o another ferrule is placed on the opposite end of the inlet tube. If 15 desired, a reduced diameter tube is fitted to the outlet of the outlet tube.

Compared to the prior art, the present invention provides a low volume puffer stem which is simple to manufacture and maintain. It is not subject to problems of corrosion and therefore does not become blocked as easily. In the event that the inlet tube does become blocked, the ferrule can be removed for ease of cleaning.

Furthermore, the ferrules allow accurate control of material to the puffer stem.

Throughout the specification, the aim has been to describe the preferred embodiments of the invention without limiting the invention to any one embodiment or specific collection of features. The description has been in terms of the use of the low volume puffer stem for delivering insecticidal dust but it will be appreciated that other fluid or fluidised materials may be delivered.

oo a.i

Claims

1. A low volume puffer stem comprising: an inlet tube having a first inlet end and second inlet end; an outlet tube communicating with said inlet tube, said outlet tube being open at one end and closed at an opposite end; communication means between said inlet tube and said outlet tube for allowing passage of material from said inlet tube to said outlet tube; and entry restriction means removably located on each end of said inlet tube; wherein said puffer stem is formed from tubular plastics material.

The low volume puffer stem of claim 1 wherein the outlet tube has a reduced internal diameter at the open end.

3. The low volume puffer stem of claim 1 wherein the communication means comprises aligned ports formed in the inlet tube "and the outlet tube.

4. The low volume puffer stem of claim 1 wherein each entry restriction means comprises a ferrule having an internal diameter approximal the external diameter of the inlet tube such that the ferrule is retained on the inlet tube by frictional engagement.

The low volume puffer stem of claim 4 wherein the ferrule includes a reduced diameter aperture for restricting the amount of 0 12 The low volume puffer stem of claim 4 wherein the ferrule includes a reduced diameter aperture for restricting the amount of material entering the inlet tube.

6. In combination, a low volume puffer stem comprising: an inlet tube having a first inlet end and second inlet end; an outlet tube communicating with said inlet tube, said outlet tube being closed at one end and open at an opposite end; communication means between said inlet tube and said outlet S° tube for allowing passage of material from said inlet tube to said outlet tube; and entry restriction means removably located on each end of said entry tube; wherein said puffer stem is formed from tubular plastics material; and 15 a hand puffer comprising a resiliently deformable bulb having a mouth receiving a plug, the plug having a bore therein with a diameter approximal the outside diameter of the outlet tube.

7. A method of forming a low volume puffer stem including the steps of bonding a first plastic inlet tube to a second plastic outlet tube such that an end of the outlet tube is bonded adjacent a middle portion of the inlet tube; blocking the end of the outlet tube bonded to the inlet tube; 13 forming a communication port between the inlet tube and the outlet tube; forming a pair of ferrules, each ferrule having a restrictive aperture in one end and an internal diameter approximal the outside diameter of the inlet tube; and fitting the ferrules to the ends of the inlet tube.

8. The method of claim 7 wherein the ferrules are retained on the inlet tube by frictional engagement. 10 DATED this Twenty-Third day of February 1998 AMALGAMATED PEST CONTROL PTY LTD By Its Patent Attorneys FISHER ADAMS KELLY .o e