WO2002064263A1

WO2002064263A1 - Valve for washing gun

Info

Publication number: WO2002064263A1
Application number: PCT/DK2001/000101
Authority: WO
Inventors: Flemming Asp; Kenneth Christensen
Original assignee: ALTO DANMARK AS
Current assignee: ALTO DANMARK AS
Priority date: 2001-02-14
Filing date: 2001-02-14
Publication date: 2002-08-22
Anticipated expiration: 2003-08-14

Abstract

The invention relates to a valve to be used in a washing gun where said valve is provided with an inlet for the washing fluid and an outlet to be connected to a nozzle, and a trigger mechanism for controlling the flow of fluid through the valve, the valve being provided with means such that the force necessary to be exerted on the trigger by the hand and fingers of the operator is independent of the static pressure of the washing fluid provided to the washing gun, whereby a more user-friendly operation with less fatigue of the muscles of the hand and the fingers of the user is obtained, and such that when said force on the trigger is removed, for instance by the operator unintentionally dropping the washing gun during operation hereof, the fluid flow from said inlet chamber to said nozzle is automatically interrupted, thus preventing possible damages caused by the washing fluid.

Description

VALVE FOR WASHING GUN

TECHNICAL FIELD

The present invention relates to washing guns used in connection with cleaning, distribution of cleansing agents etc. in industry and more particularly to the design and functioning of a valve to be used in such guns.

DESCRIPTION OF PRIOR ART

Important design considerations for valves to be used in washing guns are on the one hand to minimise that force which must be exerted by the users hand/fingers on the trigger mechanism in order to maintain the valve in an open state during operation of the washing gun and at the same time to ascertain, that if the trigger is released, for instance by the user unintentionally dropping the washing gun during operation hereof, the valve instantaneously assumes a closed state, thus avoiding possible damages to the surroundings caused by the washing fluid.

A valve of the above kind is disclosed in WO 98/47623 "Spray device with nozzle and valve", which valve comprises a tubular nozzle holder in the longitudinal direction through which a spindle can be displaced, the spindle being provided with a longitudinal, cylindrical bore receiving the washing fluid extending from one end of the spindle, and a similar longitudinal, cylindrical bore extending from the other end of the spindle and leading the fluid to the nozzle of the washer. The above-mentioned two bores are separated from each other but are each connected to the circumferential surface of the spindle, so that with a certain position of the spindle relative to the nozzle holder a fluid passage can be established between the two bores via passages suitably provided in the surrounding tubular nozzle holder. Between one end of the spindle, i.e. that end of the spindle which is connected to the nozzle, and the nozzle holder there is provided a compression spring biasing the nozzle in a direction away from the nozzle holder i.e. in the direction of the jet of fluid leaving the nozzle during operation of the washing gun. The valve is activated by the user displacing the nozzle holder in the direction towards the nozzle, i.e. against the force from said compression spring. At a certain relative displacement of the nozzle holder relative to the nozzle and to the spindle fluid communication is established between the two bores in the spindle, and fluid is ejected from the nozzle. The jet of fluid leaving the nozzle produces a reaction force on the spindle which force tends to compress the compression spring and thus keeping the valve in an open position as long as the user maintains his grip on the nozzle holder. If the user drops the washing gun, the compression spring is no longer being held in a compressed state, but returns rapidly to its original state, hence closing the valve.

It is a problem with many prior art washing guns that the force on the trigger required to activate the valve and to maintain it in a given activated state during operation of the washing gun depends on the static pressure of the washing fluid provided to the washing gun. Thus, a high static pressure will necessitate that the activation force exerted by the operator's fingers on the trigger will be stronger than in the case of a lower static pressure of the washing fluid. Furthermore, sudden changes in the static pres- sure will be felt by the operator. It is hence desirable to provide a valve for a washing gun where the control of fluid flow through the washing gun and the activation force exerted on the trigger will be independent on the static pressure of the fluid provided to the washing gun.

DISCLOSURE OF THE INVENTION

It is an object of the present invention to provide a valve to be used in a washing gun where the force necessary to activate the valve, i.e. to bring it from a closed to an open state, is independent of the static pressure of the fluid provided to the washing gun.

It is a further object of the present invention to provide a valve which automatically and rapidly closes, i.e. turns the flow of fluid off, when the user of the washing gun releases the trigger mechanism, thus avoiding damages caused by the fluid jet, if the washing gun for instance is incidentally dropped during operation hereof.

According to the invention, the first of the above objects is attained by means of a valve comprising a valve house with a longitudinal axis and provided with a fluid inlet, a fluid outlet, a control means for controlling the fluid flow between said inlet and said outlet positioned within said valve house, so that said control means can be displaced along said longitudinal axis, where said control means is characterised in that the resultant force acting on said control means in the direction of said longitudinal axis caused by the static pressure of the fluid present within said valve house is zero for any displacement of said control means within said valve house.

According to one embodiment of the present invention, there is thus provided a valve to be used in a washing gun, said valve essentially comprising a valve house subdivided into two chambers by a piston, which piston by the aid of a suitable trigger mechanism can be displaced in said valve house, such that this displacement causes the volume of one of said chambers to increase when the volume of the other chamber decreases and vice versa, where one of said chambers serves as an inlet chamber in communication with the supply of washing fluid and where there in said valve house is provided a transversal outlet opening from said valve house, such that when said trigger mechanism assumes an initial position the fluid passage from said inlet chamber to said transversal opening is completely blocked by said piston whereas said passage as the piston is being displaced away from said initial position in said valve house becomes gradually more open, thus providing increased flow of fluid from said inlet chamber to the nozzle of the washing gun, which nozzle is in fluid communication with said transversal opening, and where there is furthermore provided a fluid passage between said first and second chambers, which passage is independent of the displacement of said piston, and which passage provides the same static fluid pressure on either of the two end faces of said piston, these end faces being of equal areas, whereby the resultant force from said static fluid pressure acting on said piston in the direction of displacement hereof is always zero, no matter what static pressure of the fluid is provided by the fluid source.

The embodiment described above in principle will be described in detail in the following detailed description of the invention, where a second embodiment also based on the same inventive principle of cancellation of the static forces due to the presence of the washing fluid in the valve acting on the control means will furthermore be described.

According to the invention, said valve furthermore comprises a trigger mechanism connecting the trigger, being positioned at a suitable place for instance on the hand grip of the washing gun, with said piston in said valve house, such that a displacement of said trigger in a first direction causes a displacement of said control means in that direction in the valve house which will increase the passage between said inlet chamber and said outlet, and where a movement of said trigger in the opposite direction will cause said control means to be displaced in the opposite direction, thereby decreasing the passage between said inlet chamber and said outlet.

According to the invention, there is furthermore provided biasing means acting either on said control means or on said trigger mechanism or on both, such that the only force to be overcome by the hand/fingers of the user during activation of said trigger is caused by said biasing means and not by the static pressure of the washing fluid. The only other forces to be overcome by the hand/fingers during operation are caused by friction between the fluid flowing through the control means during operation as well as by inevitable friction between movable parts of the valve.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in more detail with reference to the accompanying drawings, in which

figure 1 is a schematic representation of the functional principle of a first embodiment of the invention;

figure 2a is a schematic representation of the functional principle of a second embodiment of the invention with the valve shown in a closed state;

figure 2b is a schematic representation of the functional principle of a second embodiment of the invention with the valve shown in an open state;

figure 3 is a first embodiment of the valve according to the invention operating accord- ing to the functional principle shown in figure 1 ;

figure 4a is a second embodiment of the valve according to the invention operating according to the functional principle shown in figure 2a, i.e. with the valve in the closed state; and figure 4b is the second embodiment of the valve according to the invention operating according to the functional principle shown in figure 2b, i.e. with the valve in an open state.

DETAILED DESCRIPTION OF THE INVENTION

In the following a detailed description of specific embodiments of the invention is given. The functional principle of a first embodiment is shown in figure 1. The valve according to this embodiment comprises essentially a tubular valve house 3, closed at one end and provided with an inlet 5 for washing fluid under a given static pressure from a suitable reservoir, not shown in the figure. Between said closed end face of the valve house 3 and the opposite end containing said inlet 5 there is in the circumferential wall of the valve house provided a lateral fluid outlet 6 for delivering the washing fluid to the nozzle of the washing gun (not shown). The flow of fluid within the valve house 3 is controlled by means of a cylindrical piston 4, sealingly displaceable within the valve house in the longitudinal direction (X) hereof. When the piston 4 is positioned in an initial position within the valve house 3, the fluid flow from the inlet 5 to the outlet 6 is blocked by the piston as shown in figure 1. When the piston is longitudinally displaced in the direction of the arrow A, a fluid passage is gradually established from the interior of the valve house 3 to the outlet 6, this passage - and thereby the flow of fluid - increasing, the further the piston 3 is displaced in the direction of the arrow A. The displacement of the piston 4 is effected by means of a suitable trigger mechanism 7, which is only schematically indicated in figure 1.

The piston 4 is provided with a longitudinal passage 8 connecting a first end face 9 of the piston 4 with a second end face 10 of the piston 4. When the valve house 3 during operation of the washing gun is filled with fluid, the static fluid pressure acting on said two end faces of the piston 4 will thus be equal, and as the projection of the areas of the end faces 9 and 10 on a plane perpendicular to the longitudinal axis X of the valve house 3 and the piston 4 are equal (said projections in this case corresponding to the actual physical areas of the end faces), the resultant force acting on the piston 4 in the longitudinal direction X caused by the static pressure of the fluid in the valve house will be zero. The only forces to be overcome during an initial displacement of the piston 4 from its initial position where the fluid flow through the valve is zero is thus inevitable frictional forces between the piston 4 and the inner circumferential surface of the valve house 3 plus forces deliberately introduced by biasing means (12) between the valve house 3 and the piston 4, as will be described below and in connection with actual embodiments of the valve shown in figure 3 and 4. When the piston does not block the lateral outlet 6 completely, a flow of fluid will take place from the inlet chamber 11 over a part of the surface of the piston 4 and through the outlet 6. This flow of fluid will give rise to a force on the piston 4 due to friction between this and the fluid, which frictional force will also have to be overcome by a force of equal magnitude and opposite direction exerted on the piston 4 by the trigger mechanism 7. When the piston becomes entirely displaced relative to the outlet 6, this force will again disappear.

Finally, there is in figure 1 shown a biasing means 12 schematically represented by a compression spring acting on the piston 4, thus biasing the piston 4 in a direction towards said initial position, in which position the flow of fluid between the inlet 5 and the outlet 6 is completely blocked. The purpose of this biasing means 12 is to ensure, that if the washing gun during operation hereof is for instance incidentally dropped, the valve automatically closes, thereby preventing possible damage to the surroundings caused by the washing fluid.

Referring to figure 2a and figure 2b there is shown the functional principle of a second embodiment of the valve according to the invention. According to this embodiment, the valve again comprises a tubular valve house 3 provided with the inlet 5 in one longitudinal end face of the valve house 3 and the outlet 6 provided in the opposite end face. Within the valve house 3 a tubular fluid control means 4 is located longitudinally dis- placeable with the aid of the trigger 7 and as in the first embodiment described in figure 1 acted upon by a biasing means 12 provided for the same purpose as before. The control means 4 comprises two cylindrical portions 4' and 4", the first portion having an outer diameter corresponding to the inner diameter of the valve house 3, so that the control means 4 can slide sealingly within the valve house 3. It is generally understood that suitable sealing means may be provided anywhere between the various parts of the elements of the valve, in cases where such sealing means are necessary in practical implementations of the invention. Such sealing means are however not shown in the figures. The second portion 4" of the control means 4 has a somewhat smaller diameter than the first portion 4', so that a circumferential passage 18 is obtained be- tween the outer surface of the second portion 4" and the corresponding inner surface of the valve house 3. The control means 4 is furthermore provided with a central passage 13 communicating with said circumferential passage 18 through an opening 14. In the valve house 3 adjacent the outlet 6 there is provided a cylindrical extension 17 of the outlet 6, the outer diameter of said extension 17 being such that it corresponds to the inner diameter of the second portion 4" of the control means 4. The second portion 4" is thus able to slide sealingly in the longitudinal direction over said extension 17. The extension 17 ends in a wall 15, and between this wall 15 and the extension 17 there is provided an opening 16. It is understood that a number of openings 14 and 16 can be distributed circumferentially around the longitudinal axis X through the valve house 3 and control means 4.

With a valve according to this embodiment, the fluid path from the inlet 5 to the outlet 6 through the valve house 3 is established via the central passage 13, from this via the opening 14 to the circumferential passage 18 and from this passage 18 via the second opening 16 to the extension 17 and hence to the outlet 6 from the valve house 3. This fluid path is shown in the blocked state in figure 2a, where the second portion 4" of the control means 4 blocks the second opening 16, and in an open state in figure 2b, where the second opening 16 is no longer blocked due to the control means 4 having in this state been displaced longitudinally in the direction indicated by the arrow A in the figure.

The fundamental principle of the invention, i.e. that the resultant force caused by the static fluid pressure on the control means in the longitudinal direction should always remain zero is also complied with in this second embodiment of the invention due to the fact that the static forces acting on the end faces b1 and d in the longitudinal direction cancels as do the forces acting in the longitudinal direction on the end faces b2 and c2. The forces to be overcome by the trigger is thus also in this embodiment the forces exerted on the control means 4 by the biasing means 12 and the various frictional forces between the valve house 3 and the control means 4 and between the control means 4 and the fluid flowing over those parts of the control means which forms part of the fluid path through the valve respectively.

Referring to figure 3, there is shown a practical embodiment of the valve according to the invention corresponding to the functional principle shown in figure 1. The valve house is in this embodiment at one longitudinal end hereof provided with an inlet chamber 11 against the inner end wall 21 of which the piston 4 is pressed by means of the biasing means 12, when the piston is located in the initial position, where the flow of fluid through the valve is blocked. The end face of the piston opposite the inlet chamber 11 is provided with a cylindrical recess for accommodation of the compres- sion spring 12 acting as the biasing means. The spring 12 is located in the spring chamber 19, which chamber is in fluid communication with the inlet chamber 11 through the central passage 13 through the piston 4. The outlet 6 is provided via a circumferential outlet chamber 20 that serves to reduce the velocity of the fluid at the contact surfaces between the fluid and the piston 4. The reduction of this velocity re- suits in reduced frictional forces between the fluid and the piston and hence a reduction of the force on the trigger 7 required to maintain the valve in a given open state.

Referring to figure 4a and figure 4b there is finally shown a practical embodiment of the valve according to the functioning principle shown in figure 2a and figure 2b. Apart from minor structural modifications the functioning of this embodiment is explained with reference to figures 2a and 2b. The length of the extension 17 of the outlet 6 is in this embodiment reduced compared to that of figure 2a and 2b, the extension being in this embodiment implemented as a groove cut in the end wall of the outlet portion of the valve house. The end face c2' corresponding to c2 in figure 2a and 2b is inclined a certain angle relative to the plane perpendicular to the longitudinal axis X through the valve house, but the projection on this plane still corresponds to the area of the end face b2 so that the static forces acting on these to faces cancels. The valve house is provided with a circumferential opening through the wall for engagement of the trigger with the control means 4', 4". A corresponding opening is of cause also provided in the valve house in the embodiment shown in figure 3 above.

Although two specific embodiments of the present invention have been shown and described in the preceding parts of the detailed description, it is understood that a person skilled in the art may conceive other embodiments of the invention without departing from the scope of the invention as defined by the following claims. Thus, for instance the passage 8 through the piston 4 according to the first of the above embodiments could be replaced by groves cut in those parts of the circumferential surface of the piston which are not brought into contact with the outlet to the nozzle, said groves providing fluid communication between said inlet chamber 11 and said spring chamber 19. PART LIST

1. washing gun

2. valve 3. valve house

4. piston

5. fluid inlet

6. fluid outlet

7. trigger 8. longitudinal passage through piston

9. first end face of piston

10. second end face of piston

11. inlet chamber

12. biasing means 13. central passage through control means

14. first opening

15. end wall of extension

16. second opening

17. extension of the outlet 18. circumferential passage

19. spring chamber

20. outlet chamber

21. inner end wall of inlet chamber

22. circumferential opening in the wall of the valve house X longitudinal axis

4' first portion of control means 4" second portion of control means

Claims

CLAIMS:

1. Valve for a washing gun said valve comprising a valve house (3) with a longitudinal axis (X) and provided with a fluid inlet (5), a fluid outlet (6), a control means (4) within said valve house (3) for controlling the flow of fluid between said inlet (5) and said outlet (6) within said valve house (3), where said control means (4) can be displaced along said longitudinal axis (X) by means of a suitable trigger mechanism (7), characterised in that the resultant static force on said control means (4) in the direction of said longitudinal axis (X) caused by the static pressure of the fluid acting on said control means (4) within said valve house (3) is zero.

2. Valve according to claim 1 , characterised in that said control means (4) has a first resultant end face (9) in a first direction of said longitudinal axis (X) and a second resultant end face (10) in the opposite direction of said longitudinal axis (X), and that there is provided a fluid passage (8) between said first end face and said second end face of said control means (4), so that the static fluid pressure on said first end face (9) is equal to the static fluid pressure on said second end face (10).

3. Valve according to claim 1 or 2, characterised in that the area of the projection of said first end face (9) on a plane perpendicular to said longitudinal axis (X) is equal to the area of the projection of said second end face (10) on a plane perpendicular to said longitudinal axis (X).

4. Valve according to any of the preceding claims, characterised in that said flow of fluid between said inlet (5) and said outlet (6) depends on the relative displacement of said control means (4) along said longitudinal axis (X).

5. Valve according to claim 4, characterised in that when said control means (4) is located in an initial position along said longitudinal axis (X) the flow of fluid between said inlet (5) and said outlet (6) is completely blocked, whereas as said control means is moved away from said initial position along the longitudinal axis (X) said flow of fluid between said inlet (5) and said outlet (6) gradually increases.

6. Valve according to claim 4 or 5, characterised in that there is provided biasing means (12) such that said control means (4) if it has been displaced away from said initial position along the longitudinal axis (X) by an activation of said trigger mechanism

(7) said control means (4) automatically resumes said initial position when the trigger mechanism (7) is no longer activated.

7. Valve according to claim 6, characterised in that said biasing means (12) is a compression spring.

8. Valve according to any of the preceding claims, characterised in that said control means (4) is a cylindrical piston comprising a first end face (9; b1 , b2) and a second end face (10; d , c2) and sealingly accommodated within said valve house (3), so that said piston is coaxially displaceable along said longitudinal axis (X) within said valve house (3).

9. Valve according to claim 8, characterised in that said fluid passage (8) between said first end face (9) and said second end face (10) of said piston (4) is formed as a canal

(8) through said piston (4).

10. Valve according to claim 8, characterised in that said fluid passage is established via a plurality of grooves provided in the circumferential surface of the piston (4).

11. Valve according to any of the preceding claims, characterised in that said fluid passage is established via one or more channels provided in the valve house (3) thereby providing fluid communication between said first end face and said second end face regardless of the longitudinal displacement of said control means (4) within said valve house (3).

12. Valve according to any of the preceding claims, characterised in that said valve house (3) is formed as a tubular body with said fluid inlet (5) provided at one longitudinal end of said tubular body, the opposite end of said tubular body being closed, and with said fluid outlet (6) provided as a lateral opening in the circumferential wall of said tubular body.

13. Valve according to any of the preceding claims 1 to 7, characterised in that said valve house (3) is formed as a tubular body with said fluid inlet (5) provided at one Ion- gitudinal end of said tubular body and with said fluid outlet (6) provided at the opposite longitudinal end of said tubular body.

14. Valve according to claim 13, characterised in that said control means (4) comprises a central passage (13) communicating with said inlet (5) and also communicating with a circumferential passage (18), where said circumferential passage (18) communicates with said outlet (6) via an opening (16) which when said control means (4) is located in said initial position along the longitudinal axis (X) is completely blocked, and which opening (16) as the control means (4) is displaced longitudinally away from said initial position becomes gradually more open as the control means (4) is displaced further away from said initial position.