Patent Description:
Food product powders may be used to produce various food products. Using such product powders are advantageous in that the powder may be stored for long periods of time without being spoiled, compared to liquid food products. The food powder may also be easily dissolved in a liquid to form the desired food product. Food products formed by powders may include dairy beverages, such as milk, non-dairy beverages, such as soft drinks, and other dairy products such as ice cream, yogurt, or cheese. Product powders may include raw materials such as sugar, milk powder, salt, or flour, and finished products such as instant formula, instant drinks, or dry broth. In producing a milk alternative that resembles fresh dairy milk, raw milk powder may be used. The raw milk powder dissolves easily in water to form a reconstituted liquid milk that may undergo further processing, including filtration, homogenization, and heat treatment, to form the final food product.

Product powders may require a mixing process which typically occurs in a sealable container including a stirring arrangement, paddle mixers, or other suitable mixing devices. After mixing occurs and the product mixture is removed from the sealable container, a residual powder may remain on the interior walls of the sealable container. A conventional method for cleaning the interior walls includes maintenance personnel manually removing the powder using compressed air. The conventional cleaning method is deficient in that the cleaning process is labor-intensive. The conventional cleaning method may also require opening the container, thereby causing the container interior to be susceptible to contamination.

Related prior art is described in patent documents <CIT> and <CIT>.

It is an object of the invention to at least partly overcome one or more limitations of the prior art. In particular, it is an object to more efficiently remove food product powder from an apparatus that is arranged to handle food product powder.

According to an aspect of the invention, an apparatus for handling a food product powder according to claim <NUM> is provided.

Accordingly, the described cleaning is not done in the traditional way, i.e. by opening the container and manually using compressed air to remove the powder from the interior surface and out of the container. Instead, the powder is removed from the interior surface using the jet nozzle that directs the air towards different surfaces of the interior, such as the ceiling and side wall, and the removed powder and air may be drawn out of the container. The apparatus for handling a food product powder described herein is advantageous in that the apparatus enables cleaning in a very efficient and sanitary manner. The container may remain closed during the cleaning process. The apparatus may include more than one jet nozzle that is arranged to direct the flow of air towards different interior surfaces of the container. The arrangement of the jet nozzles is advantageous in ensuring that the powder is removed from the different interior surfaces of the container and directed to a location to be drawn out of the container.

A method for cleaning is also described, which is used for an apparatus for handling a food product powder that includes a sealable container having an interior surface defining a volume in which the food product powder is handled, and a powder outlet. The method includes feeding air into the sealable container using a jet nozzle that is attached to the sealable container, with the air being directed by the jet nozzle towards the interior surface to remove product powder from the interior surface, directing air towards a ceiling of the interior surface using a ceiling spray opening formed on a first side of the jet nozzle, and towards a side wall of the interior surface using a side wall spray opening formed on a second side of the jet nozzle opposite the first side, and drawing air out from the sealable container, such that air and the removed product powder may flow out of the sealable container via the powder outlet.

This method may include the same features as the apparatus for handling a food product powder and shares the same advantages.

Features of the invention will now be described, by way of example, with reference to the accompanying schematic drawings.

Embodiments of the invention will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all, embodiments of the invention are shown. The invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

With reference to <FIG>, an exemplary apparatus <NUM> for handling a food product powder is shown. The apparatus <NUM> includes a sealable container <NUM> having an interior surface <NUM> that defines a volume <NUM> in which the food product powder is handled, and a powder outlet <NUM>. The apparatus <NUM> may be oriented horizontally such that the powder outlet <NUM> is arranged at a bottom of the apparatus <NUM>. One or more jet nozzles <NUM> are attached to the container <NUM> and are configured to feed air into the container <NUM> for removing residual food product powder from the container <NUM> during a cleaning process that occurs after a bulk of the food product powder is removed from the container <NUM>. The bulk of the food product powder is removed from the container <NUM> for further processing to produce a food product. Each jet nozzle <NUM> is configured to direct the air towards different surfaces of the interior surface <NUM> to remove the product powder from the interior surface <NUM>. The different surfaces include at least a ceiling <NUM> and a side wall <NUM>. After the product powder is removed from the interior surface <NUM>, the air and the removed product powder exit the container <NUM> via the powder outlet <NUM>.

Handling the food product powder in the container <NUM> may include stirring or mixing the food product powder. The food product powder may be any combination of milk powder, sugar, salt, or flour, or powder mixtures such as infant formula, cake and baking mixtures and similar food product powders.

The apparatus <NUM> may be any apparatus that handles food product powder, such as a storage tank or mixers. In the illustrated example the apparatus <NUM> is a mixer. The apparatus <NUM> has then a rotatable stirring device <NUM>, <NUM> for stirring or mixing the product powder mounted to a back wall <NUM> of the container <NUM>. The rotatable stirring device <NUM>, <NUM> extends through the volume <NUM> of the container <NUM> when the apparatus <NUM> is assembled. The rotatable stirring device <NUM>, <NUM> may include one or more rotatable shafts <NUM> that include mixing paddles <NUM>. If more than one rotatable shaft <NUM> is provided, the rotatable shafts <NUM> may be arranged to counterrotate relative to each other. The shape of the container <NUM> may be formed to accommodate rotation of the one or more rotatable shafts <NUM> and mixing paddles <NUM>.

The interior surface <NUM> of the container <NUM> is defined by the side wall <NUM>, the ceiling <NUM>, the back wall <NUM>, and a front wall arranged opposite the back wall <NUM>. The front wall may be formed as a pivotable door <NUM>. The door <NUM> may be attached to the container <NUM> via hinges and handles 12a. The ceiling <NUM> extends from the side wall <NUM> to another side wall <NUM> arranged opposite to the side wall <NUM>, and between the back wall <NUM> and the door <NUM>. The side walls <NUM>, <NUM> may be angled relative to the ceiling <NUM> that is substantially planar and extends horizontally.

The jet nozzles <NUM> are mounted to the ceiling <NUM> of the container <NUM> at a portion of the container <NUM> at which the ceiling <NUM> transitions to the side wall <NUM>. Each of the jet nozzles <NUM> are positioned to direct a flow of air towards one or more of the ceiling <NUM>, the side wall <NUM>, the rotatable stirring device <NUM>, <NUM>, and the door <NUM>. An actuator <NUM> is connected to each jet nozzle <NUM> and configured to actuate the jet nozzle <NUM> by displacing the jet nozzle <NUM> along its axis to push it into the volume <NUM>.

Any number of jet nozzles <NUM> may be provided and the arrangement of the jet nozzles <NUM> is dependent on the shape of the container <NUM>. Between two and eight, or even more jet nozzles may be provided. Six jet nozzles <NUM> may be provided including one set of three jet nozzles <NUM> being arranged on the ceiling <NUM> proximate the side wall <NUM> and a second set of three jet nozzles <NUM> being arranged on the ceiling <NUM> proximate the opposite side wall <NUM>. The two sets of jet nozzles <NUM> may be arranged tangentially relative to the ceiling <NUM> and angled inwardly toward a center of the container <NUM>. Each jet nozzle <NUM> in a same set may have a same orientation. The jet nozzles <NUM> are arranged to ensure coverage of an entire area of the interior surface <NUM>, such that product powder may be removed from the entire surface area of the interior surface <NUM>.

<FIG> shows a stem <NUM> that is connected to the actuator <NUM> of <FIG> and to the jet nozzle <NUM>. The jet nozzle <NUM> positioned in a housing <NUM> that is mounted to the container <NUM> via a flange <NUM> which may be welded to the housing <NUM>. The jet nozzle <NUM> includes inlets <NUM> that are fluidly connected between an air supply <NUM> and inlets <NUM> of the jet nozzle <NUM>, which are shown in <FIG>. The air supply <NUM> may be a pressurized tank. Four inlets <NUM> may be provided for the jet nozzle <NUM>. Fewer than four or more than four inlets may be provided and the number of inlets may correspond to the number of spray openings formed on the jet nozzle <NUM>. Each inlet <NUM> may be connected to a respective fluid supply line <NUM> and a respective control valve <NUM> such that the air supply to each inlet <NUM> may be independently controlled. The control valves <NUM> may be solenoid valves or any other suitable control valve.

<FIG> and <FIG> show the jet nozzle <NUM> having a cylindrical body <NUM> with a first cutout <NUM> formed in a first side <NUM> of the cylindrical body <NUM> and a second cutout <NUM> formed in a second side <NUM> of the cylindrical body <NUM> that is opposite the first side <NUM>. The cylindrical body <NUM> includes a first end surface <NUM> that defines the inlets <NUM>, as shown in <FIG> and a second end surface <NUM> that is opposite the first end surface <NUM>, as shown in <FIG>. When product powder is to be removed from the interior surface <NUM> of the container, the actuator <NUM> pushes the jet nozzle <NUM> into the volume <NUM> defined by the container <NUM> and air is fed through the jet nozzle <NUM>. When the product powder has been removed from the interior surface <NUM>, the actuator <NUM> retracts the jet nozzle <NUM> to a position in which the second end surface <NUM> is flush with the interior surface <NUM> of the container <NUM>.

The jet nozzle <NUM> includes a ceiling spray opening <NUM> formed on the first side <NUM> of the jet nozzle <NUM> proximate the second end surface <NUM>. When the jet nozzle <NUM> is attached to the container <NUM> and the jet nozzle <NUM> is actuated by feeding air into it when inside the volume <NUM>, the ceiling spray opening <NUM> is directed towards the ceiling <NUM> of the interior surface <NUM> to direct air towards the ceiling <NUM> shown in <FIG>.

<FIG> shows the jet nozzle <NUM> including a side wall spray opening <NUM> formed on the second side <NUM> of the jet nozzle <NUM> proximate the second end surface <NUM>. When the jet nozzle <NUM> is actuated, the side wall spray opening <NUM> is directed toward the side wall <NUM> to direct air toward the side wall <NUM> shown in <FIG>. The ceiling spray opening <NUM> and the side wall spray opening <NUM> are offset relative to a center of the respective first side <NUM> and second side <NUM>. The ceiling spray opening <NUM> and the side wall spray opening <NUM> are offset in opposite radial directions such that the ceiling spray opening <NUM> and the side wall spray opening <NUM> are positioned opposite relative to each other on the cylindrical body <NUM>.

As shown in <FIG>, the jet nozzle <NUM> may also include a shaft spray opening <NUM> that is directed downwardly toward the rotatable stirring device <NUM>, <NUM> (shown in <FIG>). The shaft spray opening <NUM> is configured to provide a fan-shaped spray pattern and may be formed on the first side <NUM> of the jet nozzle <NUM> above the ceiling spray opening <NUM>. As shown in <FIG>, the jet nozzle <NUM> may include a door spray opening <NUM> that is directed towards the door <NUM> of the container <NUM> (shown in <FIG>). The door spray opening <NUM> is inclined relative to a longitudinal axis L of the cylindrical body <NUM> and may be formed on the second side <NUM> of the jet nozzle <NUM> above the side wall spray opening <NUM>.

Advantageously, the spray openings <NUM>, <NUM>, <NUM>, <NUM> are formed in a same unitary cylindrical body <NUM> of the jet nozzle <NUM> such that one jet nozzle <NUM> is able to direct air at different surfaces of the interior of the container <NUM>. Each of the ceiling spray opening <NUM>, the side wall spray opening <NUM>, the shaft spray opening <NUM>, and the door spray opening <NUM> may be configured to provide different flow rates and different flow patterns.

In operation, when the stem <NUM> shown in <FIG> is actuated to push the jet nozzle <NUM> into the volume <NUM> of the container <NUM>, the jet nozzle <NUM> is displaced relative to the housing <NUM> that is secured to the container <NUM>. The jet nozzle <NUM> then extends out of the housing <NUM> and into the volume <NUM> of the container <NUM> to enable passage of air from the air supply <NUM> through the jet nozzle <NUM> into the container <NUM>. The jet nozzle <NUM> may be displaced to a position in which the ceiling spray opening <NUM> and the side wall spray opening <NUM> are spaced between <NUM> and <NUM> millimeters from the interior surface <NUM> of the container <NUM>. When the jet nozzle <NUM> is retracted by the stem <NUM>, the jet nozzle <NUM> is moved back into the housing <NUM> such that the housing <NUM> blocks the spray openings <NUM>, <NUM>, <NUM>, <NUM>.

<FIG> shows each of the first cutout <NUM> and the second cutout <NUM> including an upwardly directly directed surface <NUM>, <NUM>, a downwardly directed surface <NUM>, <NUM>, and a side surface <NUM>, <NUM> that extends between the upwardly directly directed surface <NUM>, <NUM> and the downwardly directed surface <NUM>, <NUM>. The side surface <NUM>, <NUM> may be substantially planar. The upwardly directed surfaces <NUM>, <NUM> and the downwardly directed surfaces <NUM>, <NUM> are angled relative to the side surface <NUM>, <NUM>. Each upwardly directed surface <NUM>, <NUM> may be angled at an angle θ that is greater than an angle α at which each downwardly directed surface <NUM>, <NUM> is angled relative to the side surface <NUM>, <NUM>. The angle θ may be between <NUM> and <NUM> degrees and the angle α may be between <NUM> and <NUM> degrees. The upwardly directed surfaces <NUM>, <NUM> may be angled at the same angle θ and the downwardly directed surfaces may be angled at the same angle α.

As shown in <FIG>, the ceiling spray opening <NUM> is formed on the side surface <NUM> of the first side <NUM> of the jet nozzle <NUM> proximate the upwardly directed surface <NUM> of the first side <NUM>. The ceiling spray opening <NUM> may be formed to be offset relative to the center of the side surface <NUM>. The shaft spray opening <NUM> may be formed on the downwardly directed surface <NUM> of the first side <NUM> of the jet nozzle <NUM>. The shaft spray opening <NUM> may be centered or nearly centered on the downwardly directed surface <NUM>.

As shown in <FIG>, the side wall spray opening <NUM> is formed on the side surface <NUM> of the second side <NUM> proximate the upwardly directed surface <NUM> of the second side <NUM>. The side wall spray opening <NUM> may be formed to be offset relative to the center of the side surface <NUM>. The door spray opening <NUM> may be formed on the downwardly directed surface <NUM> of the second side <NUM> of the jet nozzle <NUM>. The door spray opening <NUM> may be centered or nearly centered on the downwardly directed surface <NUM>. Other configurations of the ceiling spray opening <NUM>, the side wall spray opening <NUM>, the shaft spray opening <NUM>, and the door spray opening <NUM> may be possible, provided they are within the scope of the appended claims.

<FIG> shows a cross-sectional view of the cylindrical body <NUM> including the ceiling spray opening <NUM>, the side wall spray opening <NUM>, the shaft spray opening <NUM>, and the door spray opening <NUM>. Each of the door spray opening <NUM>, the ceiling spray opening <NUM>, the side wall spray opening <NUM>, and the shaft spray opening <NUM> is fluidly connected to a corresponding one of the inlets <NUM>, 21a, 21b, 21c. The inlets <NUM>, 21a, 21b, 21c are fluidly connected to the door spray opening <NUM>, the ceiling spray opening <NUM>, the side wall spray opening <NUM>, and the shaft spray opening <NUM>, respectively.

The ceiling spray opening <NUM> may include a plurality of openings that are arranged proximate each other and directed in different directions. The ceiling spray openings <NUM> are defined by cylindrical fluid passages that extend from a fluid passage 33a that is connected to the fluid inlet 21a and extends parallel to the longitudinal axis L. The cylindrical fluid passages of the ceiling spray openings <NUM> extend through the cylindrical body <NUM> of the jet nozzle <NUM> to the side surface <NUM>. Between three and seven openings may be provided. Five openings may be provided. Each opening of the ceiling spray openings <NUM> may be angled at a different angle µ relative to the longitudinal axis L and the ceiling spray openings <NUM> are angled downwardly. A mean angle µ for the set of ceiling spray openings <NUM> may be approximately <NUM> degrees, such that some of the ceiling spray openings <NUM> may be angled relative to the longitudinal axis L at angles that are larger than the mean angle µ and some of the ceiling spray openings <NUM> may be angled at angles that are smaller than the mean angle µ.

The side wall spray opening <NUM> may also include a plurality of openings that are arranged proximate each other directed in different directions. The side wall spray openings <NUM> are defined by cylindrical fluid passages that extend from a fluid passage 34a that is connected to the fluid inlet 21b and extends parallel to the longitudinal axis L. The cylindrical fluid passages of the side wall spray openings <NUM> extend through the cylindrical body <NUM> of the jet nozzle <NUM> to the side surface <NUM>. Between three and seven openings may be provided. Five openings may be provided. Each opening of the ceiling spray openings <NUM> may be angled at a different angle ω relative to the longitudinal axis L and the side wall spray openings <NUM> are angled downwardly. A mean angle µ for the set of ceiling spray openings <NUM> may be approximately <NUM> degrees, such that some of the side wall spray openings <NUM> may be angled relative to the longitudinal axis L at angles that are larger than the mean angle ω and some of the side wall spray openings <NUM> may be angled at angles that are smaller than the mean angle ω.

<FIG> shows a detailed cross-sectional view of the shaft spray opening <NUM> and the door spray opening <NUM>. An underside slot <NUM> of the door spray opening <NUM> extends along the downwardly directed surface <NUM> of the second side <NUM> and a side slot <NUM> of the door spray opening <NUM> extends from the underside slot <NUM> upwardly toward the inlet <NUM>. A flat body <NUM> of the door spray opening <NUM> defines the underside slot <NUM> and the side slot <NUM> and extends through the cylindrical body <NUM> to the inlet <NUM>. The widths of the underside slot <NUM> and the side slot <NUM> may be uniform along the length of each of the underside slot <NUM> and the side slot <NUM>. The flat body <NUM> may be inclined relative to the longitudinal axis L of the jet nozzle <NUM> (shown in <FIG>) by an angle that is between <NUM> and <NUM> degrees.

The shaft spray opening <NUM> is defined by a truncated triangular body that extends from another inlet <NUM> of the jet nozzle <NUM> through the cylindrical body <NUM> to the downwardly directed surface <NUM> of the second side. The truncated triangular shape is configured to provide a fan-shaped spray pattern outwardly from the shaft spray opening <NUM>. In contrast to the door spray opening <NUM> which includes the side slot <NUM>, the shaft spray opening <NUM> may have a single underside slot <NUM> that extends along the downwardly directed surface <NUM>.

<FIG> shows the different spray patterns provided by the ceiling spray opening <NUM>, the side wall spray opening <NUM>, the shaft spray opening <NUM>, and the door spray opening <NUM> of the jet nozzle <NUM>. The different spray patterns are directed toward different surfaces of the interior of the container <NUM> to direct air at the surfaces during the cleaning operation for the powder handling apparatus <NUM> shown in <FIG>. The first spray pattern <NUM> is provided by the ceiling spray opening <NUM> and is directed toward the ceiling <NUM>. The second spray pattern <NUM> is provided by the side wall spray opening <NUM> and is directed toward the side wall <NUM>. The third spray pattern <NUM> is directed toward the rotatable shaft <NUM> of the rotatable stirring device <NUM>, <NUM>. The fourth spray pattern <NUM> is provided by the door spray opening <NUM> and is directed toward the door <NUM>. As shown in <FIG>, each spray pattern <NUM>, <NUM>, <NUM>, <NUM> may be different.

<FIG> shows an exemplary control system <NUM> for the apparatus <NUM>. The cleaning process may be automated using the control system <NUM> which includes a processor <NUM> that is communicatively coupled with the control valves <NUM> and the actuators <NUM> for activation of the jet nozzles <NUM>. The processor <NUM> may include any suitable processors and electronic control mechanisms, such as, for example, a central processing unit (CPU), a microprocessor, control circuitry, and the like. The air supply <NUM> may include a compressor and the control system <NUM> may control the compressor to feed the air to the supply lines <NUM> at a predetermined flow rate, e.g. a flow rate that is between <NUM> and <NUM><NUM>/h. The control system <NUM> may be used to maintain constant pressure in the supply lines <NUM> for the inlets <NUM>, <NUM> shown in <FIG>.

The control system <NUM> may also be used to vary the air flow through the jet nozzles <NUM> to temporarily increase the air flow through the jet nozzles <NUM>. The control system <NUM> may be used to control the different control valves <NUM> and vary the air flow through each of the supply lines <NUM> which correspond to one of the spray openings <NUM>, <NUM>, <NUM>, <NUM> of the jet nozzle <NUM>. The flowrates at a gauge pressure of <NUM> barG for the ceiling spray opening <NUM>, the side wall spray opening <NUM>, the shaft spray opening <NUM>, and the door spray opening <NUM> may be <NUM><NUM>/h, <NUM><NUM>/h, <NUM><NUM>/h, and <NUM><NUM>/h, respectively. Any predetermined sequence of air flow in the container <NUM> may be provided using the control system <NUM>. Pulsated air flow, alternating air flow speeds, and different flow rates for different jet nozzles <NUM> or the inlets <NUM> of the jet nozzles <NUM> may be provided.

The processor <NUM> may be configured to control the actuator <NUM> shown in <FIG> to push the jet nozzle <NUM> into the volume <NUM> of the container <NUM> when product powder is to be removed from the interior surface <NUM> and retract the jet nozzle <NUM> when the product powder has been removed from the interior surface <NUM>. In operation, the control valves <NUM> may be opened after the jet nozzles <NUM> are pushed into the volume <NUM> of the container <NUM> to enable air flow through the spray openings of the jet nozzles <NUM> into the container <NUM>. A vacuum pump <NUM> may also be controlled by the processor <NUM> and fluidly connected to the container <NUM> for creating a suction effect that draws the air and the powder out of the powder outlet <NUM> of the container <NUM> shown in <FIG>. The vacuum pump <NUM> may be operable independently from the jet nozzles <NUM>. The container <NUM> may be enclosed such that air may only exit through the powder outlet <NUM>.

<FIG> shows a method <NUM> for cleaning an apparatus for handling a food product powder is shown. The apparatus <NUM> shown in <FIG> and the control system <NUM> shown in <FIG> may be used to perform the method <NUM>. The method <NUM> includes a step <NUM> of feeding air into the container <NUM> using the jet nozzles <NUM> that are attached to the container <NUM>. The air is directed by the jet nozzles <NUM> towards the interior surface <NUM> to remove product powder from the interior surface <NUM>. Step <NUM> of the method <NUM> includes directing air towards the ceiling <NUM> of the interior surface <NUM> using the ceiling spray opening <NUM> formed on the first side <NUM> of the jet nozzle <NUM>, and towards the side wall <NUM> of the interior surface <NUM> using the side wall spray opening <NUM> formed on the second side <NUM> of the jet nozzle <NUM> opposite the first side <NUM>. Step <NUM> includes letting air out from the container <NUM>, such that air and the removed product powder may flow out of the container <NUM> via the powder outlet <NUM>.

The apparatus for handling a food product powder including the jet nozzles is advantageous in providing more efficient cleaning of the apparatus. The jet nozzles in the nozzle arrangement are configured to direct a flow of air at multiple surfaces of the interior surface of the sealable container to remove the residual product powder from the interior surface. The removed product powder and the air may flow out of the container via the powder outlet and a vacuum pump, such that the manual cleaning process for the apparatus may be less intensive or eliminated. In addition to providing a more efficient cleaning process, using the nozzle arrangement advantageously enables a more sanitary cleaning process due to the container being able to remain sealed during the cleaning process.

Claim 1:
An apparatus (<NUM>) for handling a food product powder, the apparatus (<NUM>) comprising
a sealable container (<NUM>) having an interior surface (<NUM>) defining a volume (<NUM>) in which the food product powder is handled, and a powder outlet (<NUM>), and
a jet nozzle (<NUM>) that is attached to the sealable container (<NUM>) and configured to feed air into the sealable container (<NUM>) and direct the air towards the interior surface (<NUM>) to remove product powder from the interior surface (<NUM>), such that the air and the removed product powder may flow out of the sealable container (<NUM>) via the powder outlet (<NUM>),
the jet nozzle (<NUM>) comprising a ceiling spray opening (<NUM>) formed on a first side (<NUM>) of the jet nozzle (<NUM>) and directed towards a ceiling (<NUM>) of the interior surface (<NUM>), and a side wall spray opening (<NUM>) formed on a second side (<NUM>) of the jet nozzle (<NUM>) opposite the first side (<NUM>) and directed towards a side wall (<NUM>) of the interior surface (<NUM>), characterized in that
the jet nozzle (<NUM>) comprises a cylindrical body (<NUM>) that has a first cutout (<NUM>) in the first side (<NUM>) of the cylindrical body (<NUM>) and a second cutout (<NUM>) in the second side (<NUM>) of the cylindrical body (<NUM>) that is opposite the first side (<NUM>), wherein
each of the first cutout (<NUM>) and the second cutout (<NUM>) comprises, respectively, an upwardly directed surface (<NUM>, <NUM>), a downwardly directed surface (<NUM>, <NUM>) and a side surface (<NUM>, <NUM>) that extends between the upwardly and downwardly directed surfaces (<NUM>, <NUM>, <NUM>, <NUM>), and
the ceiling spray opening (<NUM>) is formed in the side surface (<NUM>) of the first side (<NUM>) proximate the upwardly directed surface (<NUM>) of the first side (<NUM>), and the side wall spray opening (<NUM>) is formed on the side surface (<NUM>) of the second side (<NUM>) proximate the upwardly directed surface (<NUM>) of the second side (<NUM>).