AU655974B2

AU655974B2 - Dusting gun

Info

Publication number: AU655974B2
Application number: AU16566/92A
Authority: AU
Inventors: Ejnar Pedersen
Original assignee: MONA SKANNERUP
Current assignee: Uni-Cleaner Europa Aps
Priority date: 1991-04-17
Filing date: 1992-04-13
Publication date: 1995-01-19
Anticipated expiration: 2012-04-13
Also published as: EP0580711A1; JP2638302B2; HU9302926D0; BR9205897A; EP0580711B1; DK170523B1; CA2108543A1; AU1656692A; DK68791D0; CA2108543C; RU2107558C1; DK68791A; WO1992018260A1; HU217286B; JPH06506868A; HUT66814A; DE69206140D1; DE69206140T2; ES2081107T3

Description

OPI DATE 17/11/92 AOJP DATE 9-/11/92 APPLN. ID 16566/92 li II PCT NUMBER PCT/DK92/00122 1lllllllIII 11111111111 111 I 1111II AU9216566 INI KNAIIUNAL AFPLILAIIUIN rUILIHrt-1 UlNULK 1 lir- rAt 1 lIN 1 LUUrtKAlIUIN I K C I (I'CT) (51) International Patent Classification 5 International Publication Number: WO 92/18260 B08B 3/02, 5/02, B05B 1/08 Al (43) International Publication Date: 29 October 1992 (29.10.92) (21) International Application Number: PCT/DK92/00122 (81) Designated States: AT, AT (European patent), AU, BB, BE (European patent), BF (OAPI patent), BG, BJ (OAPI (22) International Filing Date: 13 April 1992 (13.04.92) patent), BR, CA, CF (OAPI patent), CG (OAPI patent), CH, CH (European patent). Cl (OAPI patent), CM (OAPI patent), DE, DE (European patent), DK (Euro- Priority data: pean patent), ES, ES (European patent), FI, FR (Euro- 0687/91 17 April 1991 (17.04.91) DK pean patent), GA (OAPI patent), GB, GB (European patent). GN (OAPI patent), GR (European patent), HU, IT (European patent). JP, KP, KR, LK, LU, LU (Euro- (71) Applicants (for all designated States except US): SKAN- pean patent). MC (European patent), MG, ML (OAPI NERUP, Mona [DK/DK]; Hobrevej 5. DK-6980 Tim patent). MR (OAPI patent). MW. NL. NL (European SKANNERUP, Kristian [DK/DK]: Hobrovej 5, patent), NO. PL, RO, RU. SD, SE. SE (European pa- DK-6980 Tim tent), SN (OAPI patent). TD (OAPI patent), TG (OAPI patent), US.

(72) Inventor; and Inventor/Applicant (for US onl) PEDERSEN, Ejnar [DK/ DK]; Bryndumvej 205, DK-6715 Esbjerg N. Published With international search report.

(74) Agent: KAJ HANSEN APS; ElsegArde Skovvej 5, DK- In English translation (filed in Danish).

8400 Ebeltoft (DK).

74 (54)Title: BLAST GUN FOR COMPRESSED AIR (57) Abstract The dusting gun is of the type used for removal of dirt and for cleaning purposes, for example cleaning of agricultural implenents, motor car undercarriages before treatment of the undercarriage and similar jobs where dirt, dust, oil and other loose or firmly sticking coats are removed with compressed air. The dusting gun is peculiar in that it is equipped with an oscillating presstre discharge valve, which causes a splitting up of the air flow into periodically repeated pressure discharges. The oscillation valve acts automatically under the influence of the static and dynamic pressures of the passing air flow. In practice the pulsating air flow has proved to have markedly better cleaning properties in comparison with the usual dusting guns from which the air is given off in a continuous jet. Especially in the case of firmly sticking impurities does the pulsating air jet have a distinct loosening effect. The splitting up of the air flow into separate pressure discharges (pulses) causes a saving in the consumption of compressed air.

1 The present invention relates to a dusting gun for compressed air, more specifically to a dusting gun for compressed air, in which the dynamic effect of the air can be utilized for the removal of dirt and for cleaning purposes.

The application of compressed air for removal of dirt and for cleaning purposes is a well-known and extensively used technique. In order to produce a concentrated and controllable air jet the usual design is a pistol-like tool with an oblong air nozzle and a built-in shut-off valve.

The shut-off valve is manually operated via a pawl or similar trigger mechanism mounted in connection with the handle of the dusting gun. When the trigger mechanism is activated a concentrated air jet is let out through the nozzle, and by pointing this air jet on to the object to be cleaned it is possible to loosen or blast off dirt and impurities, such as dust, earth, oily coats, etc. The ability of the air jet to loosen old dirt and sticking 20 coats of various kinds depends on the dynamic pressure exerted by the jet, i.e. primarily the jet velocity. The greater the velocity the better the cleaning effect.

However, the jet velocity is limited to the available air pressure, usually 6 bar, and consequently an 25 increase in the cleaning effect can only be achieved by increasing the air flow. Especially for the purpose of S 0 removal of thick sticking coats will the air consumption easily be disproportionately large, and the cleaning method therefore uneconomical.

The basiq of the present invention is the desire to improve the loosening and cleaning effect of the dusting gun in relation to particularly firmly sticking impurities and at the same time achieve economy in the consumption of compressed air, According to an aspect of the present invention, there is provided a dusting gun for compressed air, in which the dynamnic effect of the air can be utilized for Sthe removal of dirt and for cleaning purposes, for example in the cleaning of agricultural implements, motor car laundercarriages and similar jobs in which dirt, dust, oil and other loose or sticking coats are removed with compressed air alone or in combination with cleaning agents, such as water, cleaning fluids, sand, abrasive grit, etc., which are supplied to the air jet immediately before it is pointed on to the object to be cleaned in order for such an additive to produce an effect of dirt-dissolution and/or abrasion, said dusting gun being of a type with built-in oscillator valve for the production of a pulsating air stream with periodically repeated pressure discharges, wherein the oscillator valve is of a type which in principle corresponds to a rapid air-blasting type, which under its own power and under the influence of the static and dynamic effects of the compressed air is designed to oscillate with a frequency of the order of 2-50 Hz, thus causing the valve alternately to open and close the air flow through the dusting gun, and wherein the oscillator valve is designed as a seat valve with a longitudinally displaceable oblong .i 20 valve body whose one end may be in sealing contact against :a valve seat shutting off the air flow through the gun under the influence of a compression spring, and whose other end incudes a piston which is displaceable within a closed cylinder, one end portion of which cylinder more "i 25 specifically the end portion distal from the seat is in fluid communication with an air duct in the dusting gun S"downstream of the seat valve via a longitudinal bore S"through the valve body, and the other end portion of which S.cylinder is in fluid connection with a pressure side of D: 30 the air duct upstream of the seat valve, preferably via a duct or bore which opens immediately in front of the seat valve.

The oscillating shut-off valve in the dusting gun has the effect that the compressed air instead of being ejected as a continuous air jet through the nozzle is here split up into a series of short pressure gusts, more i specifically as a pulsating air stream with periodically repeated pressure discharges. These periodical discharges by way of example with frequencies of 10-20 Hz involve ita time-related concentration of the pressure energy of the air so that the peak value of the dynamic pressure 39 PC I Itrnation Application 14 -05- 99 -2of the air in the individual discharge is increased as compared with the dynamic pressure that would be achieved, if the same volume of air was ejected continuously through the nozzle. As already stated, the dynamic pressure in the air jet determines the ability of the air to loosen sticking impurities and coats.

In addition to the greater dynamic pressure, the pulsating air jet also has the surprising effect of almost setting the impurities in vibrating motion under the influence of the air pulses. In the case of certain types of impurities and coats, practice has shown that this effect to a high degree contributes to increasing the cleaning effect of the dusting gun, as the vibrations cooperate in loosening the substances so that the cleaning operation is much faster, more thorough and more economical with the consumption of compressed air. The dusting gun according to the invention is therefore supposed to a certain extent to be able to replace traditional high-pressure cleaning (water-based jet cleaning) with the advantages this entails, both with regard to economy and environmental protection.

The mode of operation of tha oscillating shut-off valve is as follows: In the normal starting position the valve body is held against the valve seat in its closing/sealing position by the coil spring. When compressed air is admitted (by activation of the trigger mechanism of the gun) the pressure is increased on one side of the piston. The pressure exceeds the spring power and the valve opens, which results in a momentary discharge of compressed air and a fall in the pressure. The valve therefore closes again and the cycle is repeated. Oscillation continues as long as compressed air is admitted to the valve, i.e. as long as the trigger mechanism is kept'cactivated. The valve thus gives an automatic alternating opening and closing under the influence of the static and dynamic pressures of the compressed air of the passage of air in the dusting gun.

The oscillation action of the valve body presupposes a suitable balanced condition between the valve dimension, the mass of the valve body the moving mass) and the characteristics of the spring. It is also essential 'that the valve body can move freely, i.e. with low friction. h e-r*equen- SUBSTITUTE

SHERT

2a- The frequency depends on these factors in combination with the pressure of the compressed air.

Preferably, the dusting gun according to the invention is arranged such that said piston constitutes one end of the valve body, and is furnished with a low-friction sealing ring, for example of teflon or similar material with good sliding properties, and the sealing ring is designed and embodied to give a tight seal against the cylinder wall with the lowest possible radial pressure. Furthermore, the dusting gun according to the invention is preferably arranged such that the sealing ring is composed of a relatively thin teflon ring supported on one side by an O-ring, and wherein both rings are embedded in a ring-shaped groove in the piston. In this design the sealing arrangement satisfies the demand for low friction and ease of valve movement. An expedient measure would be to supply the valve seat or the valve body itself with a rubber-elastic coating as described in claim 4 with a view to noise level and long life of the valve.

9 *9*999 9 99 *9 39 8562e The S\"edis, Patent Office PC%, K 2 0 1 2 2 PC" 'Srnatonl Appl;cation 14 -05- 1993 -3- -cy-1ndc cn thoco factor in combnbatenw Uth p oL Lhu pressed air.

According to the invention the piston seal with advantage be embodied as described in claims 2 and 3. I is design the sealing arrangement satisfies the demand for w friction and ease of valve movement. An expedient meas would be to supply the valve seat or the valve body itsel th a rubber-elastic coating as described in claim 4 with a view L. ieunoic level and-long lifv of thQ "alve The dusting gun according to the invention-scn, like any ordinary compressed air dusting gun, be combined with an ejector for the supply of liquid or grainy material together with the air, ef. laim 5. The combination of pulsating compressed air and an additive consisting of an agent for cleaning or for solution gives a powerful increase in the cleaning effect. This procedure is used in special cases where such increase in efficiency is demanded.

The invention will be explained further in connection with the drawing in which fig. 1 is a side view of a compressed air dusting gun according to the invention, fig. 2 is an enlarged sectional view of a jet nozzle of this dusting gun, fig. 3 is a separate, enlarged longitudinal section of the oscillatory shut-off valve of the dusting gun, fig. 4 shows an ejector nozzle intended for use with addition of a liquid simultaneously with the compressed air, fig. 5 is a similar ejector nozzle intended for sand blasting.

u fig. 6 is a combined ejector/mixer valve with connections for air and Stwo different liquids simultaneously.

SUBSTITUTE SHEET Tho 0:.Yh PI/ DK 2 U I 1 2 PCT internationai Appj;ci tion 14 -05- 1993 -4- In the embodiment shown in the drawing fig. 1 the dusting gun consists essentially of a handle section 1 (pistol grip) with a trigger lever 2 and trigger guard 3, an extension barrel 4, and an exchangeable nozzle pipe 5. The nozzle pipe has an exchangeable nozzle bit 6. The latter is shown separately in fig. 2. The handle section 1 contains a not shown shut-off valve, which opens by means of a trigger lever 2, and an oscillatory pressure discharge valve. The pressure discharge valve is built into the portion of the handle section marked la. The air connection to the dusting gun takes place via a hose coupling 7. The nozzle pipe 5 is mounted on the handle section 1 by means of a knurled pipe union nut 8.

Fig. 3 is a separate sectional view of the oscillatory pressure discharge valve. The main component of the pressure discharge valve is a seat valve, whose seat is designated 9, and the valve body 10. The valve body is embodied in the shape of an oblong, rotationally symmetric body with a longitudinal bore. One end of the valve body forms a cone-shaped tightening disk 11 with a tight fit against the seat 9. A rubber coating lla is vulcanized on to the cone-shaped part 11. The opposite end of the valve body 10 constitutes a piston 12 embedded in a cylinder 13. Between the piston 12 and the cone-shaped part 11 the valve body consists of an oblong cylindrical shaft portion 14.

The longitudinal bore in the valve body in the drawing designated 15 serves to connect the hindmost part of portion 13a of the cylinder 13 to the air duct 16 after the seat valve 11, i.e. to the extension barrel 4 and the nozzle pipe 5. The valve body is held home in its seat by a compression spring coil 17 inserted in the cylinder 13 behind the piston 12.

The other side 13b of the cylinder is connected via an excentrically positioned, longitudinal bore 18 to an air chamber 19, which is located immediately in front of the seat valve on the pressure side of the latter. The direction of flow through the valve is shown with arrows The piston part 12 of the valve body is fitted with a low-friction 2 tightening ring composed of a teflon disk 21 and an O-ring 22. The O-ring serves as a supporting disk for the teflon ring, which through its contact against the cylinder wall ensures the tightness of the piston.

SUBSTITUTE

SHEET

Th-i S-?dih 'P-tint Office' 1 2 PC )n 1 4 -05- 1993 Valve dimension, size and weight of the valve body, spring characteristics, the flow ducts' cross-sectional area, etc. are mutually adjusted so that the desired oscillatory effect is created by itself immediately on the opening of the air flow (by activation of the trigger lever 2).

The oscillatory effect is explained above and will not be repeated here.

During the oscillatory motion of the valve body the passage of the compressed air through the seat valve is opened and closed, and this gives rise to the desired pulse air ',ith cyclically repeated pressure discharges. The pressure impacts from the pressure discharges are transmitted from the seat valve 9,11 and continues through the extension barrel 4, the nozzle pipe 5 and the nozzle head 6.

By exchanging the nozzle pipe 5 the dusting gun can be fitted with ejectors of various kinds, cf. figs. 4, 5 and 6. Fig. 4 shows a combined ejector and mixer valve for liquid. The liquid is supplied via a hose 23.

The nozzle pipe of the dusting gun is designated 24. A shut-off valve incorporated in the mixer valve (the ejector) shuts off the liquid supply under the influence of the pressure of the liquid and opens again automatically when the supply of compressed air is opened.

The mixer valve can alternatively serve as an ejector, i.e. with pressureless supply of liquid. The liquid will then be sucked to the ejector from a not shown tank or container by normal ejector effect, when compressed air is sent through the ejector.

Both as a tixer valve and as an ejector the quantity of liquid is adjustable by means of a flow valve positioned at the intake opening of the ejector nozzle. The flow valve is operated via a finger union nut 23a.

Fig. 5 shows an ejector for use in sand blasting. The sand is sucked to the nozzle by the ejector effect via a tubular lance 25. By regulation of the suction air through the suction hose (the so-called false air) the flow of sand can be adjusted to actual needs. Regulation is done by means of an air flow valve (volume regulation valve) 25a built into the upper end of the sand lance.

Fi. 6 shows an iniector/mixer valve 26, which in addition to an air SUBSTITUTE SHEET The Svedish Pie t r'p;p.

PCT International Application DCT/ O 2 0 2 2 14 -05- 1993 admission pipe 27 has two extra openings 28 an 29 for admixture of water and liquid chemicals, respectively. The design makes it possible to mix air water chemical in one and the same jet. This combination is useful, among other things in connection with jobs requiring disinfection or cleaning for grease.

The mixer valve can be used in the following combinations: 1) air only (both liquid intakes are plugged or otherwise closed), 2) air adjustable volume of water, 3) air adjustable volume of water adjustable volume of chemicals, 4) air adjustable volume of chemicals, air water-soluble chemical adjustable (cone.) chemical 6) air-drying after cleaning with water/chemicals.

The invention is not limited to the above shown and explained embodiment. Other types of oscillatory pressure discharge valves are also possible. The primary idea of the invention is the conversion of the static energy of the compressed air into a pulsating, concentrated air jet with high dynamic energy content in the individual pressure discharges.

f SUBSTITUTE

SHEET

Claims

1. A dusting gun for compressed air, in which the dynamic effect of the air can be utilized for the removal of dirt and for cleaning purposes, for example in the cleaning of agricultural implements, motor car undercarriages and similar jobs in which dirt, dust, oil and other loose or sticking coats are removed with compressed air alone or in combination with cleaning agents, such as water, cleaning fluids, sand, abrasive grit, etc., which are supplied to the air jet immediately before it is pointed on to the object to be cleaned in order for such an additive to produce an effect of dirt-dissolution and/or abrasion, said dusting gun being of a type with built-in oscillator valve for the production of a pulsating air stream with periodically repeated pressure discharges, wherein the oscillator valve is of a type which in principle corresponds to a rapid air-blasting type, which under its own power and under the influence of the static and dynamic effects of the compressed air is designed to oscillate with a frequency of the order of 2-50 Hz, thus causing the valve alternately to open and close the air flow through the dusting gun, and wherein the oscillator valve is designed as a seat valve with a longitudinally displaceable oblong valve body whose one end may be in sealing contact against a valve seat shutting off the air flow through the gun 0 under the influence of a compression spring, and whose 0 other end includes a piston which is displaceable within a *g 30 closed cylinder, one end portion of which cylinder more specifically the end portion distal from the seat is in fluid communication with an air duct in the dusting gun downstream of the seat valve via a longitudinal bore through the valve body, and the other end portion of which cylinder is in fluid communication with a pressure side of the air duct upstrea of the seat valve.

2. A dusting gun according to claim 1, wherein said other end portion of the cylinder is in fluid communication with the pressure side of the air duct 8 upstream of the seat valve via a duct or bore which opens immediately in front of the seat valve.

3. A dusting gun according to claim 1 or claim 2, wherein said piston constitutes one end of the valve body, and is furnished with a low-friction sealing ring, for example of teflon or similar material with good sliding properties, the sealing ring being desiqned and embodied to give a tight seal against the cylinder wall with minimal radial pressure.

4. A dusting gun according to claim 3, wherein the sealing ring is composed of a relatively thin teflon ring supported on one side by an O-ring, and wherein both rings are embedded in a ring-shaped groove in the piston. A dusting gun according to any one of claims 1 to 4, wherein the part of the valve body resting against the seat includes a rubber-elastic material, preferably of polyurethane, synthetic rubber or similar elastic material *with good fatigue strength.

6. A dusting gun according to any one of claims 1 20 to 5, where the gun includes a "pistol" portion and a nozzle portion, the pistol portion including a grip, which is supplied with a trigger mechanism (shut-off valve) for the compressed air, and where the nozzle portion is exchangeable as one unit, wherein the oscillating valve is 25 built into or incorporated in the pistol portion, and wherein, in connection with the nozzle portion, it is possible to attach an ejector part for the supply of cleaning liquid, water, sand, or other kind of admixture to the pulsating compressed air to achieve the said 30 additional effect and where the volume of water is adjustable from 0 litre/min and upwards, and in such a way that the ejector preferably can function both by the injector effect proper, i.e. self-priming, and by the supply of water/liquid at positive pressure from an external pump or a pressurized reservoir.

7. A dusting gun according to claim 6 and where the ejector is designed for liquid, wherein the ejector has a built-in shut-off valve for the liquid, the said K t f shut-off valve being designed for activation, i.e.

9- opening, under the influence oL the air pressure in the ejcector or the nozzle pipe, when the dusting gun is activated. 8. A dusting gun for compressed air substantially as herein described with reference to the accompanying drawings. DATED :31 October 1994 PHILLIPS ORMONDE FITZPATRICK Attorneys for: MONA SKANNERUP, KRISTIAN SKANNERUP Ooo7 S 0 0 S S S S S S. S S 0S S. S S S. .~S S S S S 39