EP0064695B1 - Spray pistol - Google Patents

Abstract

This invention relates to an improved sprayer means wherein the improvement comprises (a) a pressurized water feed, having a minimum pressure valve unit and leading to the mixing chamber of the nozzle spray head, which water feed is fed first to a water motor provided with a drive piston driven by the pressure of the inflowing water and then to a double-action metering pump having a metering piston coupled with said drive piston of the water motor, the cross-sectional area of the metering piston and the cross-sectional area of the drive piston being in a predetermined ratio; (b) a flexible container for chemicals residing in a detachable rigid vessel connected to a metering outlet line of the metering pump, said flexible container being connected by the mixing chamber of the nozzle spray head by a container outlet valve and a container line, the chemicals being displaced from the flexible container by water metered through the metering outlet line into the vessel; and (c) a feedback line leading from the cylinder of the metering pump to a pressure water connection valve that is capable of closing in the event of overpressure in the metering pump to shut off inflowing pressurized water.

Description

The invention relates to a spray device for metering in a chemical concentrate with a pressurized water connection, nozzle spray head with a mixing chamber and an outlet valve to be opened by a trigger, as well as a rigid container placed in a metering outlet line and displaced with the aid of the water to be metered in via a concentrate outlet valve and a concentrate line into the mixing chamber of the nozzle spray head to be emptied, flexible chemical container.

Spray devices of conventional type, for example injector sprayers or orifice metering devices, meter relatively imprecisely, that is to say that when the water flow rate changes and also when the water flow pressure changes, the percentage admixture of the metering chemical changes. The devices also lack a shutdown in the event of a lack of chemicals or a drop in water pressure.

In the case of portable sprayers specially used for crop protection, a chemical mixture in a pressure container is sprayed by air pressure through a hand nozzle. The disadvantage here is that the container must be cleaned thoroughly with water when changing chemicals. Due to the large inner surface of the containers and the pesticide residues adhering to them, a relatively large amount of the chemicals are thrown away during cleaning. This means not only a considerable loss of expensive materials, but also pollution of the groundwater.

In practice, electrical and mechanical metering pumps are also used for proportionally adding a concentrate to a water stream. A disadvantage of these pumps is that the pump elements, such as pistons and diaphragms, that is to say dynamically loaded parts, come into direct contact with the respective concentrate. In addition, the power consumption of the pumps, especially at high concentrations, is very high, since the chemical has to be brought from atmospheric pressure to the water system pressure for metering.

From US-A-2 153 240 is finally a sprayer with a pressurized water connection, a nozzle spray head with a mixing chamber and an outlet valve to be opened by a trigger, as well as a rigid container placed in a metering outlet line and by displacement with the aid of the water to be metered in via a concentrate outlet valve and a concentrate line Flexible chemical container to be emptied into the mixing chamber of the nozzle spray head.

• 1. eine vorgegebene Konzentration muß bei Druckschwankungen und Wasserdurchflußschwankungen konstant bleiben; auch die Vermischung Konzentrat/Wasser muß ohne Dosierabstand zu jedem Zeitpunkt konstant sein;
• 2. das Gerät darf erst bei dem Wasserdruck in Betrieb gesetzt werden können, bei dem ein einwandfreies Sprühbild mit dem Düsensprühkopf zu erzeugen ist;
• 3. bei Chemikalienmangel muß das Gerät automatisch abschalten;
• 4. nicht verbrauchtes Chemikalienkonzentrat muß wieder zu entnehmen sein;
• 5. die zum Dosieren erforderliche Kraft soll so klein wie möglich gehalten werden, um den Gesamt-Druckverlust des Gerätes zu verbessern und die Dosierenergie soll dem vorhandenen Wasserdruck zu entnehmen sein;
• 6. bei Chemikalienwechsel muß das Gerät problemlos zu reinigen, insbesondere mit Wasser zu spülen, sein;
• 7. das Gerät soll mobil oder stationär ausgeführt werden können;
• 8. das Konzentratgebinde muß bei Betrieb des Gerätes vollkommen zu entleeren sein;
• 9. die Dosierpumpenelemente sollen mit dem Chemikalienkonzentrat nicht in Berührung kommen; und
• 10. die Dosiervorrichtung soll ohne aufgesetzten zur Aufnahme von Chemikalien vorgesehenen Behälter nicht in Betrieb zu nehmen sein.

In contrast, the invention is based on the object of providing a device of the type mentioned at the outset with which spraying agents, such as crop protection agents and disinfectants, can be metered and sprayed independently of pressure and flow, in proportion to the quantity. In particular, the following requirements should be met:

• 1. a given concentration must remain constant with pressure fluctuations and water flow fluctuations; the mixture of concentrate and water must also be constant at all times without a dosing interval;
• 2. The device must only be able to be operated at the water pressure at which a perfect spray pattern can be generated with the nozzle spray head;
• 3. If there is a lack of chemicals, the device must switch off automatically;
• 4. unused chemical concentrate must be removed again;
• 5. the force required for dosing should be kept as small as possible in order to improve the overall pressure loss of the device and the dosing energy should be taken from the existing water pressure;
• 6. when changing chemicals, the device must be easy to clean, especially with water;
• 7. the device should be mobile or stationary;
• 8. The concentrate container must be completely emptied when operating the device;
• 9. the dosing pump elements should not come into contact with the chemical concentrate; and
• 10. The metering device should not be able to be put into operation without a container provided to hold chemicals.

For the spray device mentioned at the outset, the overall solution according to the invention is characterized by the combination of the features of the characterizing part of the independent claim.

The minimum pressure valve unit preferably contains a valve piston which blocks the water inflow from the pressurized water connection below a predetermined water pressure by the force of an elastic spring. The pressure of the water connection or the water system pressure generally does not need to be reduced within the sprayer. The rigid container containing the chemical, in particular in a flexible bladder, preferably in a disposable design, can therefore be subjected to the water system pressure during operation.

Especially with the help of the water motor that drives the dosing pump and is itself driven by water pressure, as well as by separating water and chemical in the dosing pump arrangement and by the feedback line blocking the main water connection in the dosing pump in the event of excess pressure, dosing that is independent of pressure and flow is therefore proportional to the quantity and spraying achieved.

The pressurized water supply preferably contains a multi-way valve, in particular a 4/2-way valve, with a common outlet to the nozzle spray head and to the metering pump and with further - alternately acting - outlets on the two sides of the drive piston of the water motor. As such, the suction line of the metering pump, i.e. H. the branch line leading to this pump is connected to the pressurized water supply before or after the multi-way valve. When connecting after the multi-way valve, in particular 4/2-way control unit, the differential pressure built up during operation of the device cannot influence the metering either; this circuit is therefore preferred.

The schematic representation of an exemplary embodiment explains in the following how the object on which the invention is based and its parts are solved in detail.

In the drawing, a spray gun is shown in section as an exemplary embodiment. These include a pressurized water connection 1 on the handle 2, a spray head connection 3 with mixing chamber 4 and actuating valve 5 with linkage 6 and trigger 7, as well as a metering pump, designated overall with 8, with a pump drive designed as overall with 9 designated water motor for metering proportionally one from a as Disposable bladder 10 formed chemical container coming chemical concentrate via a concentrate outlet valve 11 and a line 12 into the mixing chamber 4.

In the handle 2, the water coming from the direction of the arrow 13 (with an interposed fine sieve 14) is opposed by a piston 15 by the force of the spring 16 so that the pressurized water can only flow into the device when a certain threshold or minimum pressure is exceeded. The details of the minimum printing unit, denoted overall by 17, result directly from the drawing.

Following the minimum pressure valve unit 17, the feed water line 19 leads to a 4/2-way valve 20. The valve 20 has a first outlet 21 with a branch line 23 containing a branch 18 and a check valve 22 to the mixing chamber 4 as well as two further outlets to be acted upon alternatively 24 and 25 to the two sides of the drive piston 26 in the cylinder 27 of the water motor 9. The 4/2-way valve 20 can be switched over by a piston 28 by means of the piston 26 during the reciprocating movement of the piston.

From the branch 18 in the pressurized water inlet, a second branch line 29 leads via a check valve 30 to the double-acting metering pump 8. The metering piston 31 of the metering pump 8 is firmly coupled to the piston 26 of the water motor. It should be noted that the area ratio of the piston 26 of the water motor to the piston 31 of the metering pump must be predetermined. The remaining details of the metering pump 8 result from the accompanying drawing.

Furthermore, a rigid container 33 (which has solid walls) is placed in a metering outlet line 32 of the metering pump 8 which contains a valve 38 and is displaced with the aid of the water to be metered in (displacement principle) via the concentrate outlet valve 11 and the line 12 with the mixing chamber 4 of the Spray head connector 3 coupled flexible chemical container provided as a disposable bladder 10. The valve 38 placed in the metering outlet line 32 is closed when the container 33 is removed and is opened by plugging the container on.

Another feature of the invention explained with the aid of the spray gun is that of the pressure water supply line from the metering cylinder 34 to a rigid container 33 to be pressurized in the metering pump 8 or in the case of a rigid container 33 to be pressurized with water by the pump or when the valve 38 is blocked 36 leading feedback line 37.

• Zu 1:
  • Eine eingestellte Konzentration bleibt bei Druckschwankungen konstant, weil der Antriebskolben 26 des Wassermotors 9 und der Dosierkolben 31 der Dosierpumpe 8 in einem bestimmten Flächenverhältnis, z. B. in der Zeichnung etwa 50:1, stehen. Bei dem Umsteuern über das Gestänge 28 mit Hilfe des 4/2-Wegeventils 20 werden Druck- und Wasserdurchflußschwankungen durch langsamere bzw. schnellere Gangart des Hubantriebs ausgeglichen. Die Vermischung Konzentrat/Wasser ist zu jedem Zeitpunkt ohne Dosierabstand konstant, weil bei dem festen Kolbenverhältnis und der starren Kopplung zwischen Antriebskolben 26 und Dosierkolben 31 wegen der doppelt wirkenden Dosierpumpe 8 die zugehörige Dosierung von Wasser in dem Behälter 33 über das Ventil 38 der Leitung 32 bei jeder Bewegung des Antriebskolbens 26 erfolgt und damit das in der Blase 10 enthaltene Chemikalienkonzentrat der eindosierten Wassermenge proportional verdrängt wird.
• Zu 2:
  • Mit Hilfe der im wesentlichen aus dem Kolben 15 und der Spiralfeder 16 bestehenden Mindestdruckventileinheit 17 wird erreicht, daß das Sprühgerät erst bei einem definierten Mindestdruck mit Wasser zu beaufschlagen und demgemäß in Betrieb zu setzen ist. Entsprechend wird das Gerät bei Wasserdruckabfall unter den Schwellendruck selbsttätig durch die Einheit 17 außer Betrieb gesetzt.
• Zu 3:
  • Das Gerät schaltet auch bei Chemikalienmangel ab, weil bei entleerter Chemikalien- Blase 10 im Behälter 33 ein Überdruck entsteht, der über die Leitung 32, den Dosierzylinder 34 und die Rückkopplungsleitung 37 auf das Membranventil 35 so einwirkt, daß die Wasserzuleitung 36 gesperrt wird.
• Zu 4:
  • Da eine nicht entleerte Chemikalien-Blase 10, z. B. durch Abnehmen des gezeichneten, ein Entlüftungsventil aufweisenden Deckels des Behälters 33, jederzeit aus dem Behälter 33 zu entnehmen ist, kann bei Betrieb des Gerätes nicht verbrauchtes Chemikalienkonzentrat wieder einem Vorrat zugeführt werden.
• Zu 5:
  • Die zum Dosieren erforderliche Kraft ist sehr gering, da das Chemikalienkonzentrat in dem Behälter 33 ersichtlich bei Betrieb unter dem Wassersystemdruck steht und damit beim Dosieren nur in einen druckgleichen Raum Wasser einzubringen ist; wegen des doppelt wirkenden Antriebs der Dosierpumpe 8 wird die Dosierenergie dem vorhandenen Wasserdruck entnommen.
• Zu 6:
  • Das Gerät kann mit aufgesetztem Behälter 33 (Kartusche) problemlos gespült werden, wenn die Chemikalienkonzentratblase 10 nicht eingesteckt wird, weil das eindosierte Wasser dann unter anderem die Chemikaliendosierleitung 12 spült.
• Zu 7:
  • Die Darstellung in der Zeichnung bezieht sich auf ein als Spritzpistole ausgebildetes Handgerät, auf dessen Druckwasseranschluß 1 beispielsweise ein Wasserschlauch aufzusetzen ist; selbstverständlich kann die Vorrichtung aber auch als stationäres Gerät konzipiert werden.
• Zu 8:
  • Da der starre Behälter 33 bei Betrieb des Gerätes durch das Eindosieren von Wasser über die Leitung 32 allmählich ganz mit Wasser zu füllen ist, wird die Einwegblase 10 entsprechend allmählich ganz zusammengefaltet, so daß ein vollständiges Entleeren der eingesetzten Chemikalienblase gewährleistet ist.
• Zu 9:
  • Wie sich aus der vorhergehenden Beschreibung und der Zeichnung zweifellos ergibt, kommen die Elemente der Dosierpumpe 8 nur mit Wasser in Berührung, da das Dosieren indirekt nach dem Verdrängerprinzip - ähnlich wie bei einer Membranpumpe - erfolgt; die Trennung zwischen Wasser und Chemikal, d. h. die »Membran«, wird durch die, insbesondere als Einweggebinde darzustellende, Blase 10 bewirkt.
• Zu 10:
  • Das in der Leitung 32 zwischen Dosierpumpe 8 und Behälter 33 vorgesehene Ventil 38 wird zweckmäßig so ausgebildet, daß es erst nach Aufstecken des Behälters 33 zu öffnen ist. Die Dosiervorrichtung kann dann ohne den Behälter 33 nicht in Betrieb genommen werden; ist nämlich der Behälter 33 nicht aufgesteckt, baut die Dosierpumpe 8 in ähnlicher Weise wie bei vollständig mit Wasser gefülltem Behälter 33 und zusammengefalteter Blase, bei geschlossenem Ventil 11 einen Überdruck auf, der über die Rückkopplungsleitung 37 und das Membranventil 35 zum Absperren der Wasserzuflußleitung 36 führt.
    

The subtasks mentioned at the outset are accordingly solved by the invention in the following way:

• To 1:
  • A set concentration remains constant with pressure fluctuations, because the drive piston 26 of the water motor 9 and the metering piston 31 of the metering pump 8 in a certain area ratio, for. B. in the drawing are about 50: 1. When changing over the linkage 28 with the help of the 4/2-way valve 20, pressure and water flow fluctuations are compensated for by slower or faster gait of the linear drive. The mixing of concentrate / water is constant at all times without a metering distance, because with the fixed piston ratio and the rigid coupling between drive piston 26 and metering piston 31, due to the double-acting metering pump 8, the associated metering of water in container 33 via valve 38 of line 32 with each movement of the drive piston 26 and thus the chemical concentrate contained in the bladder 10 is displaced proportionally to the amount of water metered in.
• To 2:
  • With the aid of the minimum pressure valve unit 17 consisting essentially of the piston 15 and the spiral spring 16, it is achieved that the sprayer is only to be acted upon with water at a defined minimum pressure and is accordingly to be put into operation. Accordingly, the unit is automatically put out of operation by the unit 17 when the water pressure drops below the threshold pressure.
• To 3:
  • The device also switches off when there is a lack of chemicals, because when the chemical bladder 10 is empty, an excess pressure is created in the container 33, which acts on the diaphragm valve 35 via the line 32, the metering cylinder 34 and the feedback line 37 so that the water supply line 36 is blocked.
• To 4:
  • Since a chemical bubble 10 not emptied, e.g. B. by removing the drawn, a vent valve lid of the container 33, can be removed from the container 33 at any time, chemical concentrate which is not used up can be returned to a supply during operation of the device.
• 5:
  • The force required for dosing is very low, since the chemical concentrate in the container 33 is evidently operating under the water system pressure during operation and therefore water can only be introduced into a pressure-equal space during dosing; because of the double-acting drive of the metering pump 8, the metering energy is taken from the existing water pressure.
• 6:
  • The device can be easily rinsed with the container 33 (cartridge) attached, if the chemical concentrate bubble 10 is not inserted, because the water metered in then rinses the chemical metering line 12, among other things.
• To 7:
  • The illustration in the drawing relates to a handheld device designed as a spray gun, on the pressurized water connection 1 of which, for example, a water hose is to be placed; of course, the device can also be designed as a stationary device.
• To 8:
  • Since the rigid container 33 is gradually to be completely filled with water by metering water through the line 32 during operation of the device, the disposable bladder 10 is gradually folded up accordingly, so that a complete emptying of the chemical bubble used is ensured.
• 9:
  • As is evident from the preceding description and the drawing, the elements of the metering pump 8 only come into contact with water, since the metering takes place indirectly according to the displacement principle - similar to a diaphragm pump; the separation between water and chemical, ie the "membrane", is brought about by the bubble 10, which is to be represented in particular as a disposable container.
• To 10:
  • The valve 38 provided in the line 32 between the metering pump 8 and the container 33 is expediently designed such that it can only be opened after the container 33 has been plugged on. The metering device can then not be put into operation without the container 33; if the container 33 is not plugged in, the metering pump 8 builds up an overpressure in a similar manner to when the container 33 is completely filled with water and the bladder is folded up, with the valve 11 closed, which leads via the feedback line 37 and the diaphragm valve 35 to shut off the water supply line 36 .
    

Claims (6)

1. Spray pistol, for the metering-in of a chemical concentrate, with pressure water connection (1), nozzle spray head with mixing chamber (4) and an outlet valve (5) to be opened through an outlet (5) as well as a flexible chemical container (10), which is placed into a rigid container (33) connected to a metering output duct (32) as well as to be emptied into the mixing chamber of the nozzle spray head through a concentrate outlet valve (11) and a concentrate duct (12) by displacement with the aid of the water to be metered in, characterised by a metering pump (8) with pump drive (9) for the metering, proportionally to quantity, of the chemical concentrate coming from the chemical container (10) into a water current in the mixing chamber as well as a pressure water feed, to be controlled by way of a minimum pressure valve unit (17) to the nozzle spray head connection (3), to a water motor (9) to be controlledly driven by the pressure of the inflowing water and to the double-acting metering pump (8) with metering piston (31) coupled with a driving piston (26) of the water motor (9) and standing in predetermined ratio to its area, and by a feedback duct (37) leading from a metering cylinder (34) to a pressure water connection valve (35), which is to be closed in the case of excess pressure in the metering pump (8).

2. Spray pistol according to claim 1, characterised by a piston (15), which through the force of an elastic spring (16) blocks the water inflow out of the pressure water connection (1) below a predetermined water pressure, as minimum pressure valve unit (17).

3. Spray pistol according to claim 1 or 2, characterised thereby, that the rigid container (33) contains the chemical concentrate in a flexible bubble (10), particularly a disposable bubble.

4. Spray pistol according to one or more of the claims 1 to 3, characterised thereby, that the chemical concentrate in the container (33) in operation stands under the system pressure of the water connection (1).

5. Spray pistol according to one or more of the claims 1 to 4, characterised thereby, that a valve (38), which is closed when the container is taken off, is inserted into the connecting duct (32) between metering pump (8) and rigid container (33).

6. Spray pistol according to one or more of the claims 1 to 5, characterised by a multi-way valve (20), particularly a 4/2 way valve, which is connected into the pressure water feed or the feed duct (19) and has an outlet (21) on the one hand to the nozzle spray head (3) and on the other hand to the metering pump (8) as well as further outlets (24, 25) to the inlets of the water motor (9), which are in a given case to be acted on alternately.

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