DK179414B1

DK179414B1 - Injector rinsing function

Info

Publication number: DK179414B1
Application number: DKPA201600694A
Authority: DK
Inventors: Søren Andersen; Flemming Asp
Original assignee: Nilfisk Food As
Priority date: 2016-11-08
Filing date: 2016-11-08
Publication date: 2018-06-06
Also published as: DK201600694A1; EP3332881A1

Abstract

The present invention relates to a cleaning device a functionality for rinsing the injector from residue cleaning agents, and a method of or rinsing an injector and cleaning-agent supply channels to the injector, comprising cutting of a flow of cleaning agent to the injector and pulsing a flow of liquid through the injector.

Description

INJECTOR RINSING FUNCTION

The present invention relates to a cleaning device with a functionality for rinsing an injector of the cleaning device from residue cleaning agents. The invention also concerns a method of cleaning an injector and cleaning agents inlet channels.

Background of the invention/Background Art

In the food processing industry, in particular in heavily soiled areas, such as slaughterhouses or in the meat and fish processing industries, tenacious soiling through grease, protein and starch residues requires the application of a series of different treatments procedures, including disinfection, in order to achieve a level of cleaning that complies with official standards. Traditionally, the cleaning procedure would involve an initial flushing with water, wherein all larger debris are removed and the surfaces are made wet. Then it is customary to apply a "carpet" of foam comprising a cleaning agent over these surfaces, particularly in order to clean these surfaces from grease. Finally, the areas may be disinfected with yet another chemical agent, such as chlorine.

In connection with sucking cleaning agents into an injector of a mixing device and/or a cleaning device, residues of the cleaning agent, that are deposited in and around the injector during use. These residues may dry up and crystalize, if the injector is not used for a while. This may cause the injector to clog up and will not function correctly, until it has been dismounted and rinsed. Thus, there is a need foran integrated rinsing system.

The cleaning devices may form part of cleaning systems, where the cleaning device is connected to sources of water under pressure, pressurized air, sources of cleaning chemicals. On the output side, the cleaning device may be connected via suitable piping to points of delivery, e.g. cleaning nozzles, single or arranged on booms. These may be fixed installments in one or more rooms, in or on packing/filling machines, etc., or they may be connected via flexible hoses. US 2004/040102 discloses a foam cleaning liquid dispensing system including a cleaner cartridge, a flow control device, and an aerator. The cleaner cartridge includes a collapsible bag containing a supply of cleaning agent. The flow control device is configured to receive a flow of the cleaning agent from the cartridge and a flow of a primary cleaning liquid component. The flow control device combines the flows of cleaning agent and primary cleaning liquid component and produces an output flow of cleaning liquid at an output. The aerator includes a nozzle having an inlet fluidically coupled to the output of the flow control device, an outlet, a body having a bore extending between the inlet and the outlet, and a radial port. The nozzle is configured to receive the output flow of cleaning liquid at the inlet, inject air into the output flow of cleaning liquid through the radial port, and produce an output flow of foamed cleaning liquid through the outlet. US 2004/040102 is silent on how to rinse the cleaning liquid dispensing system itself.

Disclosure of the invention

On this background, it is an object of the present invention to provide an improved cleaning device, which is simpler in construction, and more compact, flexible and robust than the prior art cleaning devices and cleaning systems. It is a further object of the invention to provide a cleaning device where the injector may be rinsed in an easy and efficient manner.

In a first aspect, this object is achieved by a cleaning device comprising: - a mixing unit including a mixing unit housing; - at least one injector for forming foam from liquid, one or more cleaning agents, and pressurized gas; - at least one cleaning agent valve for supplying cleaning agents to said injector via a cleaning agent connection channel; - an injector valve connectable to a source of pressurized liquid and to said injector, the injector valve being operable to adjust a flow of liquid from the source of pressurized liquid; and - a control system at least configured for controlling, the at least one cleaning agent valve and the at least one injector valve, wherein the control system is further configured for closing the at least one cleaning agent valve while pulsing a water flow through the injector.

Thereby, a very simple rinsing function for cleaning device is obtained, using a minimum of components, and further a more efficient rinsing of an injector and the cleaning-agent supply channels to the injector.

Alternatively or additionally, the object of the invention may be achieved in a second aspect of the invention involving a cleaning device comprising: - a mixing unit including a mixing unit housing; - at least one injector for forming foam from liquid, one or more cleaning agents, and pressurized gas; - at least one cleaning agent valve for supplying cleaning agents to said injector via a cleaning agent connection channel; - an adjustable source of pressurized liquid in fluid communication with said injector, the adjustable source of pressurized liquid being operable to adjust a flow of liquid through the injector; and - a control system at least configured for controlling, the at least one cleaning agent valve and the at least one injector valve, wherein the control system is further configured for closing the at least one cleaning agent valve while pulsing a water flow through the injector.

In an embodiment thereof the adjustable source of pressurized liquid is a variable pump.

In a third aspect, the object is obtained by a method for rinsing an injector and cleaning-agent supply channels to the injector, said method comprising - providing a cleaning agent valve for adjusting the flow of a cleaning agent to the injector; - providing o an injector valve in a fluid connection between a source of pressurized liquid and the injector the injector valve being operable to adjust a flow of liquid from the source of pressurized liquid to the injector and/or o an adjustable source pressurized liquid, such as a variable pump; - operating the cleaning agent valve to cut-off a flow of cleaning agent to the injector, and - while the a flow of cleaning agent to the injector is cut of, operating the injector valve or the source of pressurized liquid or the adjustable source pressurized liquid to pulse a liquid flow through the injector.

Further objects, features, advantages and properties of the cleaning system and cleaning device e according to the invention will become apparent from the detailed description.

Brief description of the drawings

In the following detailed portion of the present description, the invention will be explained in more detail with reference to the exemplary embodiments shown in the drawings, in which:

Fig. 1 shows a prior art cleaning device;

Fig. 2, in a sectional view, shows a diagrammatic depiction of a mixing unit for a cleaning device according to the present invention, and with an injector mounted in the mixing unit;

Fig. 3 shows the mixing unit of Fig. 2, with an injector dismounted from the mixing unit;

Fig. 4A, in a perspective view, shows an embodiment of a mixing unit according to the invention;

Fig. 4B, in a perspective view, shows the mixing unit of Fig. 4A from a different angle;

Fig. 5, in diagrammatic form, shows a cleaning system according to one aspect of the invention including a cleaning device according to another aspect of the invention, and an extended cleaning system;

Fig. 6, in a sectional view, shows details of a mixing unit according to the invention; Fig. 7, in a partly sectional, perspective view, shows parts of a cleaning device according to an embodiment of the invention, where the rinsing system for rinsing an injector is provided;

Fig. 8, in a sectional view, illustrates an alternative method and system for rinsing an injector of a cleaning device according to an aspect of the invention; and Fig. 9 shows a section through the injector of Fig. 3.

Detailed description of the invention

In the following detailed description of the cleaning device and the method of rinsing an injector according to the invention will be described by preferred embodiments. Also, described herein is a cleaning system in which the cleaning device and the method may preferably be implemented. Further beneficial details of a cleaning device are also disclosed, although the invention may be implemented in other cleaning devices and cleaning systems. The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. The invention may however be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like reference numerals refer to like elements throughout. Like elements may therefore not be described in detail with respect to the description of each figure.

The present invention concerns a cleaning device 2 within the field of automated hygienic systems for cleaning of process-systems/apparatuses in the food processing industry. The invention further concerns an integrated mixing unit or module 10 for handling liquid (preferably water), gas (preferably air), and different chemical cleaning compounds, hereinafter called cleaning agents. The mixing unit 10 comprises a suction vacuum chamber, preferably in the form of a so-called injector 100 for mixing water, air and one or more cleaning agents.

In a further aspect of the invention, the mixing unit 9 of the cleaning device 2 may further include a function for integrated flushing or rinsing of the mixing chamber(s), i.e. the injector(s).

The mixing unit 10 varies from the mixing units of existing cleaning devices, in that all functions may be integrated in one and the same compact module/unit. This contrasts the cleaning systems available in the market for the food processing industry today. These prior art cleaning devices are typically constructed from different and independent standard components, which via tubes, weldings, fittings and valves (see e.g. Fig. 1) are connected into a cleaning manifold.

Fig. 1 shows a prior art cleaning device for room surfaces cleaning in the food processing industry. The cleaning device shown is representative of the prior art cleaning devices for surface cleaning in the food processing industry. Other types of apparatuses are used in connection with CIP cleaning.

In Fig. 1, the encircled device indicated by the reference AA is a cleaning agent valve with tubing. The cleaning agent valve AA includes an injector, which is encircled by the smaller circle inside circle AA, and with the reference “aa”. The injector aa is mounted inside the shown tubing by matching threading inside the tube and on the injector. An example of such an injector can be seen in WO 2015/067989. The injector housing, i.e. the tubing is welded together, making it difficult to access the injector for maintenance or repair.

In Fig. 1, the encircled devices indicated by the references BB and CC are further cleaning agent valves with tubing, similar to AA described above. Further, the encircled device indicated by the reference DD is a valve for supplying spraying water directly to a surface to be cleaned, without being mixed with a cleaning agent, i.e. the valve circumvents the cleaning agent valves AA, BB, CC. Further, in Fig. 1, the arrow marked with the reference Wl indicates the incoming water from a pump, delivering water under pressure. Yet further, the arrow marked with the reference OU indicates the outlet for water, wa-ter/cleaning agent mix, or water/cleaning agent/air-mix. The encircled device indicated by the reference EE is a valve for supplying air to water/cleaning agent mix in order to provide a foam. The structure encircled and named FF is a valve and tubing for supplying water for rinsing the injectors, aa, in the cleaning agent valves AA, BB, CC. In connection with an aspect of the present invention, such an additional valve may be completely spared, due to the new setup.

As is apparent from Fig. 1, the prior art system is a large and complex construction.

The cleaning device and the cleaning system according to the present invention integrates some or all the functionalities of the prior art devices in one compact module for automated surface cleaning, in order reduce the space requirements, the production time, and to improve the overall hygiene in the cleaning device 2 and system 1, based on a hygienic design without weldings and with a minimum of connections.

Fig. 5 shows a first exemplary embodiment of cleaning device 2 and a cleaning system 1, which is particular suitable for performing cleaning in the food processing industry, in particular surface cleaning (as opposed to e.g. CIP).

The cleaning system 1 comprises a cleaning device 2, and an external cleaning system 300, and a control system 200. The external cleaning system 300 may comprise a tubing 310, 311, 312, 313, in order to deliver water, foam and cleaning agents/water mix from the cleaning device 2 to the locations to be cleaned, e.g. surfaces of rooms and/or machinery of a food processing facility.

The illustrated cleaning device 2 comprises a source of liquid 49. The source of liquid 49 may include a liquid pump 41. The liquid is preferably water. The liquid pump 41 has a pump inlet 41’ to be connected to a liquid (water) supply (not shown), such as regular municipal tap water, and an outlet 41 ” for the provision of pressurized water.

The cleaning device 2 also comprises a source 51 of pressurized gas, preferably comprising a compressor 51, having an air inlet (not shown), and a gas outlet 51’ for the provision of pressurized gas, such as air. In other embodiments (not shown) other pressurized gasses may be used, e.g. O2.

The cleaning device 2 also comprises one or more sources 33, 34 of cleaning agents. In Fig. 5 two such sources are shown. However, in other embodiments there may be another number of cleaning agent sources, such as one or three or more.

It is understood that, in other embodiments (as explained in the general description above), the cleaning device 2 could be embodied without a compressor 51 or a water pump 41 or sources 33, 34 of cleaning agents, or without either. Alternatively, either the compressor 51 or the water pump 41 or the sources 33, 34 of cleaning agents could form part of the device 2, but be placed at a different location.

Furthermore, as indicated in Fig. 5, the cleaning device 2 comprises a mixing unit 9. The mixing unit 9 allows mixing of liquid, e.g. water, with a cleaning agent, and a gas, e.g. air, to provide a foam for cleaning purposes. The mixing unit 9, according to the invention may also allow spraying with water only, or spraying with a mixture of cleaning agent and water (i.e. without gas/air).

The mixing unit 9 has a liquid inlet 43, which is fluidly connectable to the outlet 41” of the water pump 41 via suitable liquid supply tubing 42. The mixing unit 9 further comprises a fluid outlet 44. The water flow through the mixing unit 9 may be controlled by an injector valve 40, which is a flow control valve, i.e. a valve for controlling the magnitude or volume of water flowing there through per unit of time. The valve may be a ball valve, or a seat valve, or any other suitable valve. The injector valve 40 is located in the mixing unit 9 in a liquid supply channel 64’, 64 forming a fluid connection between the liquid inlet 43 and an injector 100 of the mixing unit 9. Although this may not be necessary, a second flow control valve, a spraying liquid valve 80 is shown inside the mixing unit 9 in Fig. 5. The valve may be of the same type as the injector valve 40. The spraying liquid valve 80 is arranged in a fluid connection 81, 82 between the liquid inlet 43 and the liquid outlet 44 of the mixing unit 9. This spraying liquid valve 80 may be used for providing clean water for spraying in the external cleaning system 300.

Further, the mixing unit 9 has a gas inlet 53, which is fluidly connected the gas outlet 51 ’ of the source of pressurized gas/compressor 51 via suitable gas piping 52. The flow of gas (air) to the mixing unit may be controlled by a gas supply valve 50, which in the embodiment shown in Fig. 5 is provided in the fluid connection piping 52 between the source of pressurized gas/compressor 51 and the gas inlet 53 of the mixing unit 9. However, in other embodiments (not shown) the gas supply valve 50 may be arranged inside the mixing unit 9.

Yet further, the mixing unit 9 has a number of cleaning agent inlets 37, 38, 39, which are fluidly connected with the cleaning agent sources 33, 34, via cleaning agent input lines 35, 36, which as formed by suitable tubes or pipes. The flow of cleaning agents to the mixing device 9 may be controlled by cleaning agent valves 30, 31 arranged in the respective cleaning agent input lines 35, 36. In alternative embodiments (not shown) cleaning agent valves may instead be located inside the mixing unit 9.

The cleaning device 2 may further be connected to an electrical power supply (not shown) via a suitable cable (not shown) in order to supply electrical power to the water pump 41 and the compressor 51, and/or any further valves, actuators as described below, and the control system 200 for the cleaning device 2 and cleaning system 1.

The water pump 41, the compressor 50, the mixing unit 9, and further components of the cleaning device 2 may placed inside a housing, not shown. However, they may also be distributed in different locations and connected via suitable tubing.

The illustrated mixing unit 9 may be a wall or floor mountable device, but it could in alternative embodiments be placed on a wheeled chassis, whereby a mobile cleaning device 2 could be provided.

The pressurized water provided by the water pump 41, i.e. at the pump outlet 41 ”, may have has a pressure of between 3 bar and 60 bar, preferably between 10 bar and 60 bar, even more preferably between 20 bar and 60 bar. Hereby is achieved that sufficient pressure is provided by the water pump 41 in order to suck (see explanation of injector function below) a first cleaning agent and/or a second cleaning agent, even when an air pressure provided by the compressor 51 (for foaming) is supplied to an injector 100 of the mixing unit 9. This will be explained below. The air pressure provided by the compressor 51 is preferably around 5-10 bar.

Water vapor can carry contagious/infectious gems, which can pose a real health hazard to the operators performing cleaning work in for example the food industry. However, by keeping the water pressure below 60 bar or below 40 bar, it is assured that the health risk associated with water vapor carried infections is minimized, while at the same time providing sufficient pressure in order to suck up the first or second cleaning agent for cleaning or disinfection purposes. Preferably, the water provided by the water supply to the inlet 41’ of the water pump 41 has a pressure of less than 10 bar, preferably less than 8 bar.

Further, and as shown in Fig. 5, the cleaning system 1 and the cleaning device 2 comprises a control system 200, for controlling the operation of the cleaning device 2 and in some embodiments the external cleaning system 300, which may form part of the cleaning system 1 of the invention.

The control system 200 controls at least the cleaning device 2. The control system 200 comprises a control unit 201. The control unit 201 may be any suitable electronic processing unit available. The control unit 201 may be connected to various sensors and actuators via suitable cables or wirelessly.

Thus, the control unit 201 may control the operation of the pump 41, which forms part of the source of liquid/water for the cleaning device 2. The pump 41 may preferably be a variable pump driven by a motor 210, connected to and controlled by the control unit 201, via a control connection 211. As mentioned above the control connection may be a cable or a wireless connection.

The control unit 201 also may control the operation of the injector valve 40. The injector valve 40 may be controlled by an actuator 240, connected to and controlled by the control unit 201, via a control connection 241. As mentioned above the control connection 241 may be a cable or a wireless connection. In Fig. 5, the actuator 241 is represented by the symbol of a magnetic actuator, and is illustrated within the mixing unit 9. However, it must be emphasized that the actuator 240 may in other embodiments, see e.g. Figs. 4A, 4B, physically be located outside of and adjacent to the mixing unit 9 housing 10, and connected to the injector valve 40 via e.g. a shaft extending through a wall of the housing 10. Further, it must be emphasized that the actuator 240 may be of a different type than a magnetic actuator. For the injector valve the actuator may e.g. be a pneumatic actuator (which may be supplied by the compressor 51 (not shown) or by an additional source of pressurized gas or fluid (not shown)), which in itself may be controlled by an electrical actuator such as a magnetic actuator.

Further, the control unit 201 also may control the operation of the spraying liquid valve 80. The spraying liquid valve 80 may be controlled by an actuator 280, connected to and controlled by the control unit 201, via a control connection 281. As mentioned above the control connection 281 may be a cable or a wireless connection. In Fig. 5, the actuator 280 is represented by the symbol of a magnetic actuator, and is illustrated within the mixing unit 9. However, it must be emphasized that the actuator 280 may in other embodiments, see e.g. Figs. 4A, 4B, physically be located outside of and adjacent to the mixing unit 9 housing 10, and connected to the spraying liquid valve 80 via e.g. a shaft extending through a wall of the housing 10. Further, it must be emphasized that the actuator 280 may be of a different type than a magnetic actuator. For the spraying liquid valve 80, the actuator may e.g. be a pneumatic actuator (which may be supplied by the compressor 51 (not shown) or by an additional source of pressurized gas or fluid (not shown)), which in itself may be controlled by an electrical actuator such as a magnetic actuator.

Yet further, the control unit 201 may control the operation of the gas supply valve 50. The gas supply valve 50 may be controlled by an actuator 250, connected to and controlled by the control unit 201, via a control connection 251. As mentioned above the control connection 251 may be a cable or a wireless connection. In Fig. 5, the actuator 250 is represented by the symbol of a magnetic actuator, and is illustrated outside the housing 10 of the mixing unit 9, along with the gas supply valve 50. However, it must be emphasized that the actuator 250 and the gas supply valve may in other embodiments (not shown), physically be located inside the mixing unit 9 housing 10. Alternatively, in a further embodiment (not shown), the gas supply valve 50 may be located inside the housing 10 of the mixing unit 9, and the actuator 250 may be located externally of and adjacent to housing 10 of the mixing unit 9, and connected to the gas supply valve 50 via e.g. a shaft extending through a wall of the housing 10. Further, it must be emphasized that the actuator 250 may be of a different type than a magnetic actuator.

Yet further, the control unit 201 may control the operation of the each of the cleaning agent valves 30, 31. The cleaning agent valves 30, 31 may be controlled by actuators 230, 232 connected to and controlled by the control unit 201, via control connections 231, 233, respectively. As mentioned above the control connections 231, 233 may be cables or wireless connections. In Fig. 5, the actuators 230, 232 are represented by the symbol of a magnetic actuator, and are illustrated as located outside the housing 10 of the mixing unit 9, along with the cleaning agent valves 30, 31. However, it must be emphasized that the actuators 230, 232 and the cleaning agent valves 30, 31 may in other embodiments (not shown), physically be located inside the mixing unit 9 housing 10. Alternatively, in a further embodiment (not shown), on or more of the cleaning agent valves 30, 31 may be located inside the housing 10 of the mixing unit 9, and one or more of the actuators 230, 232 may be located externally of and adjacent to housing 10 of the mixing unit 9, and be connected to the cleaning agent valve 30, 31 via e.g. a shaft extending through a wall of the housing 10. Further, it must be emphasized that the actuators 230, 232 may be of a different type than a magnetic actuator.

Fig. 5 further shows that the cleaning device 2 according to the invention may be connected to an extended cleaning system 300. A suitable piping 310 of the extended cleaning system 300 may be connected to the liquid outlet 44 of the mixing unit 9. The piping 310 may extend to a plurality of locations where cleaning is expected to be necessary, e.g. different rooms or machines, such as food packing machines, etc. The piping may thus have several branches 311,312,313 supplying water, mixture of water and a cleaning agent or foam to cleaning outlets 331, 332, 333. In Fig. 5 three branches 311, 312, 313 are shown. It will however be appreciated that alternatively the tubing 310 may branch into only two, or several more branches, or not branch of at all.

Further, each cleaning outlet 331, 332, 333 may comprise delivery nozzles 340. Each cleaning outlet 331, 332, 333 may comprise a number of delivery nozzles 340. In Fig. 5 it has been shown that cleaning outlet 331 has five delivery nozzles 340, cleaning outlet 334 has three delivery nozzles 340, and cleaning outlet 333 has one delivery nozzles. It is however evident, that the number of delivery nozzles 340 may be adapted to the purpose.

The supply of water, water/cleaning agent mixture or foam to the cleaning outlet may be controlled by outlet control valves 321,322, 323. The outlet control valves 321,322, 323 may in turn be controlled by the control system 200. Thus, the control unit 201 may control the operation of the each of the outlet control valves 321, 322, 323. The outlet control valves 321, 322, 323 may be controlled by actuators 261, 262, 263 connected to and controlled by the control unit 201, via control connections 270, 271,272, 273. As mentioned above the control connections 270, 271,272, 273 may be cables or wireless connections. In Fig. 5, the actuators 261,262, 263 are represented by the symbol of a magnetic actuator. It must be emphasized that the actuators 261,262, 263 may be of a different type than a magnetic actuator.

Fig. 2 shows an embodiment of a mixing unit 9, which forms part of a cleaning device 2 according to one aspect of the invention. The mixing unit 9 comprises a housing 10. Inside the housing 10, the mixing unit 9 has a mixing chamber located inside an injector 100. The injector 100 is arranged inside the housing 10.

The mixing unit utilizes the injector principle for mixing a water and one or more cleaning agent. The injector principle utilizes that when water is under pressure is led through a channel with a decreasing and increasing cross-sectional area (in the direction of the flow of the water) and a channel is formed to intersect the water flow chamber, then a vacuum is formed in the intersecting channel. This vacuum sucks a cleaning agent into the chamber where the water flows. There, the cleaning agent starts to mix with the water. Thus, the cleaning agent may be transported into the flowing water without the use of pumps. This principle is well known and will not be discussed further. Also, known in the art, is to subsequently add gas/air under pressure to the water/cleaning agent mixture in order to provide a foam. Various principles for adding air/gas for foaming are known in the art, and provides foam of varying qualities and quantities. One principle is to let the gas/air impinge on the stream of water/cleaning agent mixture. Another, principle is inject air/gas in parallel with the flow of water/cleaning agent mixture. Both of the principles may be used in the present context. However, further below a specific embodiment of the latter principle is described.

Fig. 2 shows a cross section of an embodiment of a mixing unit 9 for supplying foam and/or water/cleaning agent mixture and/or pure water for cleaning. The illustrated mixing unit 9 comprises a housing 10 having a liquid/water inlet 43 for receiving pressurized liquid/water. The water is supplied to the water inlet 43 via a suitable pipe, liquid supply tubing 42, as described above. The liquid supply tubing 42 may be connected to the mixing unit via a connector 43’, which may secured to the mixing unit 9, e.g. by cooperating threading (not shown) on the mixing unit 9 and connector 43’, or by other fastening means. Further, the connection may be water tight by application of a suitable gasket 43” such as an O-ring.

The housing 10 also has a gas inlet 53 for receiving pressurized gas, preferably air from compressor 51 as described above. The gas inlet 53 may comprise a connector 53’, allowing easy connection to the hose, tube, or pipe forming the gas piping 52 described in connection with Fig. 5 above. The connector 53’ may be connected to the mixing device 9, e.g. by cooperating threading (not shown) on the mixing unit 9 and connector 53’, or by other fastening means. Further, the connection may be water tight by application of a suitable gasket (not shown), such as an O-ring.

The housing 10 also comprises a fluid outlet 44 for said foam and/or water/cleaning agent mixture and/or pure water. The fluid outlet 44 may comprise a connector 44’, allowing easy connection to the hose, tube, or pipe forming the tubing of external cleaning system 310 described in connection with Fig. 5 above. The connector 44’ may be connected to the mixing device 9, e.g. by cooperating threading (not shown) on the mixing unit 9 and connector 44’, or by other fastening means. Further, the connection may be water tight by application of a suitable gasket 44’” such as an O-ring.

The housing 10 also comprises at least one cleaning agent inlet 37. The cleaning agent inlet 37 may comprise a connector 37’, allowing easy connection to the hose, tube, or pipe forming the cleaning agent input line described in connection with Fig. 5 above. The connector 37’ may be connected to the mixing device 9, e.g. by cooperating threading (not shown) on the mixing unit 9 and connector 37’, or by other fastening means. Further, the connection may be water tight by application of a suitable gasket (not shown) such as an O-ring. In some embodiments, the cleaning agent connector 37’ (or connectors) may be one-way valves in order to prevent a back flow of cleaning agent.

The gas/air is supplied to the housing 10 via a suitable pipe 52, which is preferable connected with a compressor 51, and the first cleaning agent is supplied to the housing 10 via a suitable pipe 35, which is in fluid communication with a reservoir 33. The water pipe 42 is fluidly connectable to a water pump 41 for supplying pressurized water to the housing 10 of the mixing unit 9.

The mixing unit 9 further comprises an injector 100 positioned inside the housing 10. The injector is received in an injector receiving port 70 in the housing 10, as may be appreciated by comparing e.g. Figs. 2 and 3. Fig. 3 shows the injector 100 removed from the injector receiving port 70, and Fig. 2 shows the injector 100 in place in the injector receiving port 70. The injector 100 is in fluid communication with the fluid outlet 44 via a turbulence chamber 14 formed inside the housing 10 between the injector receiving port 70 and the fluid outlet 44. Preferably, and as shown in e.g. Fig. 3, the injector receiving port 70 opens into the turbulence chamber 14. Also, preferably, and as shown in e.g. Fig. 3, the turbulence chamber 14 opens into the fluid outlet 44 of the mixing unit 9. In the turbulence chamber 14 the water/cleaning agent mix is mixed with air in order to provide foam.

As shown in Figs. 2 and 3, the mixing unit further comprises an injector valve 40 formed within the housing 10. The flow of liquid (water) through the mixing unit 9 may be controlled by the injector valve 40, which is a flow control valve, i.e. a valve for controlling the magnitude or volume of water flowing there through per unit of time. The valve may be a ball valve, a seat valve, or any other suitable valve. The injector valve 40 is in fluid connection with the liquid inlet 43 via a channel 64’. The injector valve 40 is further in fluid connection with the injector 100 via a liquid supply channel 64, that opens into the above-mentioned injector receiving port 70. Thus, the injector valve 40 is located in the mixing unit 9 in a liquid supply channel 64, 64’ forming a fluid connection between the liquid inlet 43 and an injector 100 of the mixing unit 9.

As shown in e.g. Figs. 2, 3 and 5, a second flow control valve, a spraying liquid valve 80 may preferably be arranged inside the housing 10 of the mixing unit 9. The valve may be of the same type as the injector valve 40. The spraying liquid valve 80 is in fluid communication with the liquid inlet 43 via a channel 81 formed in the housing 10. Further, the spraying liquid valve 80 is in fluid communication with the turbulence chamber 14, and thereby the fluid outlet 44. Thus, the spraying liquid valve 80 is arranged in a fluid connection 81, 82 between the liquid inlet 43 and the liquid outlet 44 of the mixing unit 9. This spraying liquid valve 80 may be used for providing clean water for spraying in the external cleaning system 300.

As shown in Figs 2 and 3, the liquid inlet 43 is preferably in fluid communication with a distribution chamber 13. The distribution chamber opens into the liquid inlet 43. The channel 64’ to the injector valve 40 and the channel 81 to the spraying liquid valve 80 thus extend from the distribution camber 14.

The injector valve 40 is preferably arranged in an injector valve port 74. The injector valve port 74 is arranged within the housing 10, and adapted for receiving the injector valve 40. Thus, the above mentioned channel 64’ opens into the injector port 74 at one (downstream) end and into the distribution chamber 13 at the other (upstream) end.

The spraying liquid valve 80 is preferably arranged in a spraying liquid valve port 78. The spraying liquid valve port 78 is arranged within the housing 10, and adapted for receiving the spraying liquid valve port 78. Thus, the above mentioned channel 81 opens into the spraying liquid valve port 78 at one (downstream) end, and into the distribution chamber 13 at the other (upstream) end.

As described above, in not shown embodiments, an actuator 240 for operating the injector valve may further be arranged inside the housing, and preferably adjacent to the injector valve port 74. However, in the illustrated embodiments, see Figs 4A and B, the actuator 240 is arranged external to the mixing unit 9 housing 10, but adjacent to a sidewall thereof. A shaft (not shown) extends from the actuator 240 to the injector valve port 74 via a channel or passage (not shown) from the sidewall, where the actuator 240 is located, to the injector valve port 74.

As also described above, in not shown embodiments, an actuator 280 for operating the spraying liquid valve 80 may further be arranged inside the housing, and preferably adjacent to the spraying liquid valve port 78. However, in the illustrated embodiments, see Figs 4A and B, the actuator 280 is arranged external to the mixing unit 9 housing 10, but adjacent to a sidewall thereof. A shaft (not shown) extends from the actuator 280 to the spraying liquid valve port 78 via a channel or passage (not shown) from the sidewall, where the actuator 280 is located, to the spraying liquid valve port 78.

As shown in Figs 2 and 3, in some embodiments, a further channel 15 may extend from the distribution chamber 13 an outlet 16 formed in a sidewall of the housing 10. As shown in Figs. 4A and B, the outlet 16 may be formed through a connector 16’. The connector 16’ may allow easy mounting of a hose for manual cleaning in the vicinity of the mixing unit 9.

In further embodiments (not shown) the mixing unit may comprise more than one injector 100, such as two or three or more formed inside the housing. In this case each injector may be arranged in injector receiving port as described above and fluidly connected to a fluid outlet and to the liquid inlet as described above. In the case where the mixing unit 9 comprises more than one injector 100, the mixing unit may have one injector valve 40 per injector, each arranged in an injector valve port 74 as described above. However, it may also be possible that a plurality of injectors may be connected to a single injector valve 40 arranged in a single injector valve port 74, as described above. In this case a selector mechanism may be integrated into the housing 10 of the mixing unit 9, the selector mechanism being arranged to switch between liquid supply channel 64 in the mixing unit leading to each of the injectors 100. Such a selector mechanism may further be connected to the control system 200 via an actuator, which may be integrated inside the housing 10, or be located externally thereto.

However, an advantage of the mixing unit 9, the cleaning device 2 and the cleaning system 1 according to the invention is that one and only one injector is necessary.

Preferably, the at least one injector 100 and the injector valve 40 are integrated within the mixing unit housing 10. Preferably, the cleaning agent connection channels 61, 62, 63 for fluidly connecting the at least one injector 100 and the sources of cleaning agent 33, 34 are formed within the mixing unit housing 10. Preferably, the liquid supply channel 64 for fluidly connecting the injector valve 40 with the injector 100 is formed within the mixing unit housing 10. Preferably, the gas supply channel 65, for fluidly connecting the gas supply valve 50 and the at least one injector 100 is formed inside the mixing unit housing 10.

As also mentioned above, the injector 100 (or each injector 100) may be connected to a plurality of sources 33,34 of cleaning agents. In Figs. 2 and 3, for the sake of simplicity, only one cleaning agent connection channel 61 is shown, the leaning agent connection channel 61 extending from a cleaning agent inlet 37 of the mixing unit 9 to the injector 100. In the diagram of Fig. 5, two sources 33, 34 of cleaning agent are illustrated. As may be appreciated from Fig. 6 a cleaning agent connection channel 61, 62, 63 may extend from each cleaning agent inlet 37, 38, 39, at an outer surface of the mixing unit 9 housing 10, to the injector 100. Thus, the embodiment shown in Fig. 6, stipulates three cleaning agent connection channels 61, 62, 63. We note however, that there may be more cleaning agent connection channels. As shown, a cleaning agent connection channel 61 may either extend directly from the cleaning agent outlet 37 to the injector 100 (actually the injector receiving port 70) or two (or more) inlets 38, 39 may merge via cleaning agent connection channels 62, 63, into a common cleaning agent connection channel 60 formed inside the housing 10 of the mixing unit 9. In Fig. 6, the cleaning agent channels 61, 62, 63 in the mixing unit 9 are shown to extend from openings in different sidewalls of the mixing device. However, they may also all be formed in the same sidewall. The cleaning agent channels 61, 62, 63 may be distributed in a three dimensional pattern around the injector receiving port 70.

Fig. 2 shows the injector 100 inserted in the mixing unit 9 housing 10. Fig. 3 shows the injector when separated from the housing. Details of the injector 100 can be appreciated from Fig. 3. However, Fig. 9 show more details of the injector 100.

Fig. 9 shows a section through an injector 100 according to an aspect of the invention. The injector 100 has an injector body 101. The injector body 101 is elongate, generally cylindrical in structure. Thus, injector 100 has a longitudinal axis A. The elongate injector body 101 has first end 102 and a second end 103 opposite to the first end 102.

An elongate injector chamber 110 is formed centrally within in the injector body 101. The injector chamber 110 comprises two sections, a first section 111 and a second section 112 opening into an injector outlet 113. The injector outlet 113 is formed in an end wall 114 of the injector body 101, at the second end 103 (the outlet end of the injector 100). At the end opposite to the injector outlet 113, the first section 111 of the injector chamber 110 has an injector inlet 115. The injector inlet 115 also is in fluid connection with one or more cleaning agent bores 116,117. In Fig. 9, two cleaning agent bores 116,117 are shown in the injector body 101 extending in a direction perpendicularly to the longitudinal axis A of the injector 100. It will be appreciated, that in other, not shown embodiments, the injector 100 may comprise one or three, or four or more cleaning agent bores 116, 117. It may also be noted, that the cleaning agent bores 116, 117 does not necessarily need to be formed perpendicularly to the longitudinal axis A of the injector 100, but may more generally be formed at an angle with the longitudinal axis A, however such that the cleaning agent bores 116, 117 will intersect with the injector chamber 110 at the injector inlet 115. Each of the cleaning agent bores 116, 117 has an inlet 116’, 117’, respectively, at an outer surface 118 of the injector body 101.

It may further be appreciated, that the inlet 116’, 117’ of the cleaning agent bores 116, 117 are formed at a place where the outer surface 118 of the injector body 101 has a circumferential groove, cleaning agent groove 119. The cleaning agent groove 119 forms an annular cleaning agent channel 120 (see Fig. 2) around the injector 100 together with the inner surface of the injector receiving port 70 of the mixing unit 9 housing 10, when the injector 100 is inserted in the injector receiving port 70 as shown in Fig. 2. The annular cleaning agent channel 120 serves to distribute the cleaning agent. Further, it is clear that the cleaning agent connection channel 61 of the mixing unit housing 10 opens into the annular cleaning agent channel 120 in an inlet 121 thereto (Figs 2 and 3)·

In order to secure that cleaning agent only goes into the annular cleaning agent channel 120 not into the remainder of the injector receiving port 70 suitable gaskets, such as O-rings may be arranged in annular grooves, gasket grooves 122, 123, which are formed in the outer surface 118 of the injector body 101, and on either side of the cleaning agent groove 119. In alternative embodiments (not shown), gaskets may instead be provided in grooves formed in the surface of the injector receiving port 70.

Further, the injector comprises an injector water inlet 124. The injector water inlet 124 is formed as a bore from the outer surface 118 of the injector body 101 and into the injector body 101 in a transverse direction to the longitudinal axis A of the injector 100. The injector water inlet 124 communicates with a water inlet connection channel 125 formed in the longitudinal direction of the injector 100 (parallel to longitudinal axis A) that opens into the injector chamber 110 at the injector inlet 115.

It may further be appreciated, that the injector water inlet 124 is formed at a place where the outer surface 118 of the injector body 101 has a circumferential groove, water inlet groove 126. The water inlet groove 126 forms an annular water inlet channel 127 (see Fig. 2) around the injector 100 together with a portion of the inner surface of the injector receiving port 70 of the mixing unit 9 housing 10, when the injector 100 is inserted in the injector receiving port 70 as shown in Fig. 2. The annular water inlet channel 127 serves to distribute the water. Further it is clear that the liquid supply channel 64 in the mixing unit housing 10 opens into the annular water inlet channel 127 in an inlet 128 thereto (Figs 2 and 3).

In order to secure that water only goes into the annular water inlet channel 127, and not into the remainder of the injector receiving port 70 suitable gaskets, such as O-rings may be arranged in annular grooves, gasket grooves 122,129, which are formed in the outer surface 118 of the injector body 101, and on either side of the water inlet groove 126. In alternative embodiments (not shown), gaskets may instead be provided in grooves formed in the surface of the injector receiving port 70.

Thereby, pressurized liquid, preferably in the form of water, may be transported from the pump 141 via the liquid supply channel 64 in the mixing unit housing 10 into the annular water inlet channel 127 and further into the injector water inlet 124, and the water inlet connection channel 125 passing the injector inlet 115, and further into the injector chamber 110 and out the injector outlet 113. When the pressurized water passes the injector inlet 115, a vacuum is created in the cleaning agent bores 116, 117 and further the in annular cleaning agent channel 120. Thereby, cleaning agent will be sucked from the cleaning agent source 33, 34 into the annular cleaning agent channel 120 via the cleaning agent connection channel 61 of the mixing unit housing 10. In the injection chamber 110, water and cleaning agent is thereby mixed.

The injector outlet 113 is fluidly connected to the fluid outlet 44 of the housing 10 via a turbulence chamber 14 formed within the housing 10. As illustrated in e.g. Fig. 9, the injector inlet 115 has a narrower cross section than the cross section of the injector outlet 113.

As will be further appreciated from Fig. 3 and Fig. 9, the outer surface 118 of the injector body 101 has a further circumferential groove, gas groove 130. The gas groove 130 forms an annular gas inlet channel 131 (see Fig. 2) around the injector 100 together with a portion of the inner surface of the injector receiving port 70 of the housing 10 of the mixing unit 9, when the injector 100 is inserted in the injector receiving port 70 as shown in Fig. 2. The annular gas inlet channel 131 serves to distribute the gas (air). Further it is clear that gas supply channel 65 in mixing unit housing 10 opens into the annular gas inlet channel 131 in an inlet 132 thereto (Figs 2 and 3). When the injector 100 is in place in the injector receiving port 70 in the mixing unit 9, the annular gas inlet channel 131 is in fluid communication with the turbulence chamber 14, via one or more helical grooves 133 formed in the outer surface 118 of a portion 134 of the injector body 101, and via a gap 135 between a cylindrical end portion 136 at the second (outlet) end 103 of the injector body and the inner surface of the injector receiving port 70. The one or more helical grooves 133 formed in the outer surface 118 forms a helical channel 137 between the helical groove 133 and the inner surface of the injector receiving port 70, when the injector is in place in the injector receiving port 70 as shown in Fig. 2.

Thereby, the helical grooves 133 and the gap 135 forms a swirling stream of air around the stream of water and cleaning agent mixture exiting from the injector outlet 113. Experiments has shown that this provides an improved foaming effect.

We note that the helical grooves 133 are only used in certain aspects of the invention. In other aspects of the invention an acceptable foaming effect may be obtained using other types of air injection as mentioned above.

We also note, that in principle, the helical grooves may alternatively be formed in the surface of the injector receiving port 70 (not shown).

When, as described above, the injector 100 has an injector water inlet 124 formed in a direction transverse to a longitudinal axis A of the injector 110 it allows the insertion and retraction of the injector 100 from the housing 10 of the mixing unit 9, through a wall 22 thereof. This means that instead of the cleaning device comprising numerous injectors, with various capacities for providing foam and/or water/cleaning agent mixture, the injector may instead easily be exchanged with another injector 100 with a different capacity.

The interchangeability of the injectors 100 is further supported by the above described cleaning device 2 where the injector 100 has an elongate injector body 101 with a first end 102 and an outlet end 103 opposite to the first end 102; the outlet end 103 has smaller maximum dimension d2, than a maximum dimension d1 of the injector body at the first end 102; wherein the injector body 101 only has a decreasing maximum dimension from the first end 102 to the outlet end 103, wherein the injector body 101 comprises means for releaseably connecting the injector to a portion 70 of the housing 10 of the mixing unit 9.

The maximum dimension d1 and d2 of the injector body 101 at the first end 102 and at the outlet end 103 is the largest cross sectional extent (perpendicular to the longitudinal axis A) of the injector body at those locations. Preferably, the injector body 101 is cylindrical, or formed from generally cylindrical portions 134,136,143,144,145. In that case the maximum dimensions corresponds to diameters. In the shown embodiments the maximum dimension d1 at the first end 102 is the dimension (diameter) of the portion 145 of the injector body. In the shown embodiments the maximum dimension d2 at the outlet end 103 is the dimension (diameter) of the portion 134 of the injector body 101, wherein the helical grooves 133 are formed.

By the injector body 101 only having a decreasing maximum dimension from the first end 102 to the outlet end 103, is meant that none of the portions 144, 143, in between the two maximum dimension d1 and d2 exceeds that of a previous portion as seen from the first end 102 to the outlet end 103. In this context, the above-mentioned grooves 119, 126, 130 and the gasket grooves 122. 123, 129 are not counted with. Further, the gaskets (O-rings) 138,139, 140 are not counted either as these are at least partly compressible.

By the injector body 101 comprising means for releaseably connecting the injector 100 to a portion 70 of the housing 10 of the mixing unit 9 is meant e.g. that one or more of the cylindrical portions 143, 144, or 145 may be provided with means such as a threading (141, not shown in Fig. 9), which is configured to cooperate with connection means, such as corresponding threading (142 not shown in Fig. 9) in a section of the injector receiving port 70 in the mixing unit 9. Apart from threading, other connection means known in the art may be used e.g. latches, bayonet fixtures, etc.

We note that, corresponding to the maximum dimensions of the cylindrical portions 135, 143, 144, or 145, the injector receiving port 70 comprises sections 70-1, 70-2, 70-3 and 70-4 of increasing maximum dimensions from the end at the turbulence chamber 14 to the opposite end.

As mentioned above the mixing unit housing 10 is preferably formed as a solid block 11 of material, and the at least one injector 100 is arranged in an injector receiving port 70 which is formed as a bore in the block 11. Further, the injector valve 40, is arranged in an injector receiving port 74 formed as a bore in the block 11). Yet further, the cleaning agent connection channels 61,62, 63, the water supply channel 64 and the gas supply channel 65 are preferably formed as bores in the block 11.

Thus, preferably, the housing 10 is formed from a solid block 11 of a uniform material as an integrated unit. The illustrated mixing unit 9 may preferably be manufactured from a metal alloy, e.g. stainless steel. Hereby, a robust mixing unit 9, which can withstand pressures up to 60 bar without malfunction or any noticeable leakage may be obtained. Also, it is obtained that weldings may be omitted or reduced in relation to the fluid connections of the cleaning device 2.

The block 11 may as shown in Figs 4A and B be an elongate box shaped structure, having two end surfaces 20, 21 and four side surfaces 22, 23, 24, 25. However, in not shown embodiments, the block 11 may have other shapes e.g. cylindrical.

The injector 100 may be arranged in a bore of stepwise decreasing maximum dimension (injector receiving port 70) in the block 11, this bore being provided in one side surface (a bottom surface) 22 of the block 11. The fluid outlet 44 of the mixing unit 9 may be provided through an opposite side surface 23 (top surface). The turbulence chamber 14 is preferably provided as a bore through this side surface 23.

The cleaning agent connection channel 61,62, 63, and the gas supply channel 65 may preferably be formed as bores through on or both of further sidewalls 24, 25, as are the bores for shafts for connecting the actuators 240, 280 to the injector valve 40 and the spraying liquid valve 80, respectively.

The injector valve 40 and the spraying liquid valve 80 are, as described above, arranged in an injector valve port 74 and a spraying liquid valve port 78, respectively. These ports 74, 78 may, in not shown embodiments, be formed as bores through one of the free sidewalls 22, 23, 24, 25.

However, in a preferred embodiment, and as shown in Figs. 2 and 3, the block 11 may preferably comprise a main block portion 11’ and a lid block portion 11”. The lid block portion 11 ’’may be provided in extension of an end wall 20’ of the main block portion 11’. The lid block portion 11” is preferably formed in the same material as the main block portion 11’. The distribution chamber 13, the liquid inlet 43, and the channels 81 and 64’ are preferably provide as bores in the lid block portion 11”. The injector valve port 74 and a spraying liquid valve port 78 are then formed as bores in through the main block portion 11’, and the lid block portion 11” is then used to secure the injector valve 40 and the spraying liquid valve 80 in the injector valve port 74 and a spraying liquid valve port 78. The lid block portion 11” may be connected to the main portion 1T by use of suitable fasteners, such as bolts (not shown).

Returning now to Fig. 9, the injector 100 may preferably comprise a tool receiving lock 146 arranged at the portion 145 of the injector 100 at the first end thereof. The tool receiving lock 146 is preferably formed as a depression in the end wall 104 of the injector 100, opposite the injector outlet 113. Preferably, the tool receiving lock 146 has a polygonal cross sectional shape (in a plane perpendicular to the longitudinal axis A), e.g. a hexagonal shape. The tool receiving lock 146 may thereby allow rotation of the injector by a tool (not shown) having a correspondingly shaped cross-sectional shape. Thereby, the injector may be secured in the injector receiving port 70 - or released therefrom.

Fig. 7, in a partly sectional, perspective view, shows an embodiment of the housing 10 of the mixing unit 9 according to a further aspect of the invention, where the cleaning device 2 further comprises means for rinsing the inlet 121 of a cleaning agent connection channel 61,62, 63 of the mixing unit 9 housing 10, where the cleaning agent connection channel 61, 62, 63 opens into the injector receiving port 70, or more particularly, where the cleaning agent connection channel 61, 62, 63 opens into the annular cleaning agent channel 120 formed between the injector receiving port 70 and cleaning agent groove 119, when the injector is inserted in the injector receiving port 70, as described above.

In connection with sucking cleaning agents into the injector 100, residues of the cleaning agent, that are deposited in and around the injector 100 during use, may dry up and crystalize, if the injector is not used for a while. This may cause the injector to clog up and will not function correctly, until it has been dismounted and rinsed. Thus, there is a need for an integrated rinsing system as indicated.

Fig. 7 shows that the housing 10 of the mixing unit 9 may be substantially as described above. Fig. 7 also shows an injector 100, which is partly released from the injector receiving port 70. Also shown in the figure are three cleaning agent connectors 37’, 38’, 39’ corresponding to those described above and arranged in inlets 37, 38, 39 of cleaning agent connection channels 61, 62, 63, respectively. In Fig. 7, the cleaning agent connection channels 61,62, 63 converge into a common cleaning agent connection channel 60 as is described above in connection with Fig. 6. However, the rinsing system may also be applied to embodiments, where the cleaning agent connection channels 61,62, 63 are individual channels. Fig. 7 further discloses a rinsing channel 66 for providing rinsing water to the area around the connection 121. The water is provided via a source of water 49, which is preferably the same pump 41 as described above. The pump 41 has a fluid connection to a rinsing valve (not shown in Fig. 7), which may be provided inside the housing 10, or externally. This rinsing valve is operated by an actuator 290, which may be connected to the control unit 201 of the control system either by suitable cable or wirelessly (not shown in Fig. 5). Thereby, areas exposed to cleaning agents can be rinsed by water entering through the rinsing channel 66 and out through the injector 100.

Fig. 8 illustrates a more preferred embodiment of a rinsing function for a cleaning device according to this aspect of the invention. Fig. 8 shows a section through a mixing device 9 with an injector 100, basically as described above in connection to Figs. 2-7 and Fig. 9. A cleaning agent connector 37’ is arranged in a cleaning agent inlet 37 of the mixing unit 9. The cleaning agent connector 37’ is preferably connected to a cleaning agent valve 30 as described in connection with Fig. 5 above, and via a suitable tubing, such as a rubber or plastic tubing. Thus, the rinsing function according to this embodiment does not require any further channels (bores, tubing) or valves and actuators. Instead, the rinsing function is provided by the cleaning device 2 having the function build into a control system 200 as described above, wherein the control system 200 is connected to the actuators 230, 232 of the cleaning agent valve 30, 31, and wherein the control unit 201 is connected to the actuator 240 of the injector valve 40, and where the control system 200 is configured to shut of the cleaning agent valve 30, 31, while - at the same time - controlling the actuator 240 of the injector valve 40 to pulse the water flow through the injector 100, i.e. to turn on and off the water flow through the injector 100. This provides a flow back and forth in the cleaning agent connection channels 61,62, 63.

When the injector 100 is considered to need to be rinsed, the one or more cleaning agent valves 30, 31 are closed. Consequently, the cleaning agent(s) is prevented from flowing to the injector 100, while water is still allowed to flowthrough the injector 100 (in pulses). Thereby, a pulsing suction is provided in the cleaning agent connection channels 61,62, 63 inside the mixing unit 9, but possibly also in the tubing 35, 36, and a part of the cleaning agent residues in the cleaning agent connection channels 61, 62, 63 and/or in the tubing 35, 36, will be sucked into and through the injector 100, and into the tubing 310 of external cleaning system 300. This may occur because of a flexibility of the tubing 35, 36, which, when a suction is provided, may become marginally thinner. The volume of the tubing 35, 35 thus becomes smaller. When the water flow through the injector 100 is cut of, the vacuum will disappear and the tubing return to it’s normal volume. Thereby, cleaning agent residues, in and around the injector 100 will be withdrawn to the tubing 35, 36. By repeating this process (i.e. pulsing) a number of times, the channels and the chamber 120 (i.e. the annular cleaning agent channel between the injector receiving port 70 and cleaning agent groove 119) around the injector 100 will be emptied completely from cleaning agent residues, and only water will remain..

In a further aspect, the previously described rinsing function may be implemented in a method for operating a cleaning device 2 as described above, and where the method comprises the steps of closing a cleaning agent valve 30, 31, while controlling the actuator 240 of the injector valve 40 to pulse the water flow through the injector 100.

It is a challenge, when shutting down a high velocity, high pressure liquid flow through a valve, to avoid pressure shocks backwards in the system. The phenomenon is also called water hammering, or simply hammering. In the case of cleaning systems 1 as described above, pressure shocks, or hammering, will have an impact on the life expectancy of pump 41, sensors, gaskets and other components in the effected location.

According to a further aspect of the invention, hammering may be reduced by shutting down valves such as the injector valve 40 slowly. But, since users of a cleaning system 1, may freely exchange valves as they see fit, a manufacturer of a cleaning system 1 may not control the closing rate of all valves. Consequently, the water hammering may be significant in practical systems. The injector valves 40 and outlet valves 321, 322, 323, described in connection with the cleaning system 1 above, may be adapted to minimize water hammering when leaving the factory. But, if the valves are replaced at the customer side, water hammering may again become a problem. Therefore, there is a need to build-in a function that may reduce water-hammering in cleaning systems 1, such as described above. The problem may be solved by a suitable control implemented in the control system 200 of the cleaning system 1 described above. In this control system 200, knowledge of the times at which the individual valves are to be opened and closed is built-in. As a consequence, it will be possible to regulate the pressure a short interval of time before a scheduled or intended closing of a particular valve.

The control involves regulating the pressure provided by pump 41, alternatively stopping the pump 41 all-together, a number of seconds, such as 1-10 seconds, preferably such as 1-5 seconds, before a valve is to be closed. By this regulation it will be possible to reduce the velocity of the water flow in a branch 310, 311,312, 313 of a fluid distribution system, such as the extended cleaning system 300 of Fig. 5. Thereby, the water hammering is minimized, and a prolonged life of the components of the cleaning system may be obtained.

Although the teaching of this application has been described in detail for purpose of illustration, it is understood that such detail is solely for that purpose, and variations can be made therein by those skilled in the art without departing from the scope of the teaching of this application.

The term "comprising" as used in the claims does not exclude other elements or steps. The term "a" or "an" as used in the claims does not exclude a plurality. The single processor or other unit may fulfill the functions of several means recited in the claims.

List of reference numbers A longitudinal axis of injector 1 cleaning system 2 cleaning device 9 mixing unit 10 housing of mixing unit 11 block 11’ main part of block 11 ” lid part of block 13 distribution chamber of mixing unit 14 turbulence chamber of mixing unit 15 channel from distribution chamber 16 outlet of channel from distribution chamber 16’ connector at outlet of channel from distribution chamber 20 end surface (outer surface) of housing of mixing unit 21 end surface (outer surface) of housing of mixing unit 22 side surface/bottom surface (outer surface) of housing of mixing unit 23 side surface/top surface (outer surface) of housing of mixing unit 24 side surface (outer surface) of housing of mixing unit 25 side surface (outer surface) of housing of mixing unit 30 cleaning agent valve - valve for regulating flow of cleaning agent from a 1st source of a cleaning agent 31 cleaning agent valve - valve for regulating flow of cleaning agent from a 2nd source of a cleaning agent 32 valve for regulating flow of cleaning agent from a 3rd source of a cleaning agent 33 1st source of a cleaning agent, reservoir 34 2nd source of a cleaning agent, reservoir 35 cleaning agent input line 36 cleaning agent input line 37 cleaning agent inlet of mixing unit 37’ cleaning agent connector 38 cleaning agent inlet of mixing unit 38’ cleaning agent connector 39 cleaning agent inlet of mixing unit 39’ cleaning agent connector 40 injector valve 41 source of liquid, pump 41’ pump inlet 41” pump outlet 42 liquid supply tubing 43 liquid inlet of mixing unit 43’ connector, liquid connector 43” gasket 44 fluid outlet of mixing unit 44’ connector, gas connector 44” gasket 49 source of liquid 50 gas supply valve 51 source of pressurized gas, compressor 52 gas piping 51 ’ gas outlet of source of pressurized gas/compressor 53 gas inlet of mixing unit 53’ connector, gas connector. 61 first cleaning agent connection channel in mixing unit 62 second cleaning agent connection channel in mixing unit 63 third cleaning agent connection channel in mixing unit 64 liquid supply channel in mixing unit 65 gas supply channel in mixing unit 66 rinsing channel 70 injector receiving port in mixing unit 74 injector valve receiving port in mixing unit 78 spraying liquid valve receiving port in mixing unit 80 spraying liquid valve 81 fluid connection between the liquid inlet 43 and the spraying liquid valve 80 in mixing unit 82 fluid connection between the spraying liquid valve 80 and the liquid outlet 44 in mixing unit 100 injector 101 injector body

Claims

A purifier (2) comprising: - a mixing unit (9) comprising a mixing unit housing (10); - at least one injector (100) for forming foam from liquid, one or more pressurized cleaners and gases; and - at least one detergent valve (30, 31) for delivering detergent to the injector via a detergent connecting channel (61, 62, 63); characterized in that the purifier further comprises - an injector valve (40) which can be connected to a source of pressurized liquid (41, 49) and to the injector (100), wherein the injector valve is adapted to adjust a flow of liquid from the source of pressurized liquid (41.49); and - a control system (200) arranged at least to control the at least one cleaner valve (30, 31) and the at least one injector valve (40), the control system further being adapted to close the at least one cleaner valve (30, 31) while controlling the injector valve (40) to pulse a fluid flow through the injector (100).

A purifier (2) comprising: - a mixing unit (9) comprising a mixing unit housing; - at least one injector (100) for forming foam from liquid, one or more pressurized cleaners and gases; and - at least one detergent valve (30, 31) for delivering detergent to the injector via a detergent connecting channel (61, 62, 63); characterized in that the purifier further comprises - an adjustable source of pressurized fluid (41,49) which is in fluid communication with the injector (100), wherein the adjustable source of pressurized fluid (41, 49) can be adjusted to adjust a fluid flow through the injector (100); and - a control system (200) at least adapted to control the at least one detergent valve (30, 31) and the at least one injector valve (40), the control system further being arranged to close the at least one detergent valve (30, 31) while the fluid flow through the injector (100) is pulsed.

A purifier (2) according to claim 2, wherein the adjustable source of pressurized fluid (41, 49) is an adjustable pump (41).

A method of purifying an injector (100) and detergent channels (61.62, 63) for the injector (100), the method comprising: - providing a detergent valve (30, 31) for controlling a flow of a detergent to an injector (100); - providing an injection valve (40) for fluid connection (42, 64 ', 64) between a pressurized source of fluid (41, 49) and the injector (100), wherein the injector valve is adapted to control a fluid flow from the source to pressurized liquid (41, 49) for the injector (100); and / or o an adjustable source of pressurized fluid (41, 49), such as an adjustable pump (41); characterized in that the method comprises - controlling the cleaner valve (30, 31) to shut off a flow of cleaner to the injector (100), and - while the flow of cleaner to the injector (100) is closed off, controlling the injector valve or the source of pressurized liquid (41, 49) or the adjustable source of liquid vacuum (41, 49) to pulse a fluid flow through the injector (100).