Patent Description:
Warewash machines have become fairly standardized in the industry. Typically, a standard warewasher has a washing chamber with an access opening that allows wares to be placed within the chamber for a washing operation. A typical hood-type warewash machine includes a housing that, in part, defines a wash zone having front, left and right access openings, and at least one spray arm disposed above and/or below the wash zone. A multi-sided hood assembly is movable between a down/closed position for washing and an up/open position for inlet and outlet of wares. In the closed position, the multi-sided hood assembly closes the front, left and right access openings, and in the open position, the front, left and right access openings are open to permit access to the wash zone for inlet and egress of wares.

During a wash and rinse cycle of a hood-type machine, the chamber fills with hot water vapor. When the cycle is complete, and the operator raises the hood/door, a large amount of hot water vapor exits the machine, making for an uncomfortable work environment. The hot water vapor that leaves the machine also rises to the ceiling and can contact the facility walls, causing the ceiling to drip water and generally creating a hot work environment that may need to be conditioned, increasing facility costs.

It would be desirable to provide a hood-type machine that adequately addresses the issues associated with hot water vapor escape. <CIT> relates to a warewash machine with vapor extraction unit.

In one aspect, a warewash machine includes a housing that at least in part defines a chamber with a wash zone, the chamber having front, left and right access openings. At least one spray arm is disposed above or below the wash zone, the spray arm configured to spray liquid toward the wash zone. A multi-sided hood assembly includes multiple wall sections, the multi-sided hood assembly movable between a lowered and closed position for washing and a raised and open position for inlet and outlet of wares, wherein in the raised and open position each of the multiple wall sections is raised. An air exchange system is fluidly connected with the chamber and includes an extraction compartment and an intake compartment, both the extraction compartment and the intake compartment located externally of the chamber. The extraction compartment includes a condenser therein, wherein an incoming water path to the machine from a cold water input passes through the condenser. The extraction compartment includes an air outlet to a surrounding ambient environment, a first air mover associated with the extraction compartment and selectively controllable for moving hot water vapor from the chamber, into the extraction compartment, over the condenser and out of the air outlet. The intake compartment includes at a least one heater therein and an air inlet from the surrounding ambient environment, and a second air mover associated with the intake compartment and selectively controllable for moving ambient air into the intake compartment via the air inlet, past the heater to be heated and into the chamber.

The details of one or more embodiments are set forth in the accompanying drawing and the description below. Other features, objects, and advantages will be apparent from the description and drawing, and from the claims.

Referring to <FIG>, a warewash machine <NUM> includes a housing <NUM> (e.g., with support frame and panels) in part defining a chamber <NUM> with a wash zone <NUM>. The chamber <NUM> includes front <NUM>, left <NUM> and right <NUM> access openings through which wares can be moved in and out of the chamber for cleaning. One or more spray arms (e.g., wash arm(s) 23a and rinse arm(s) 23b having respective wash nozzles and rinse nozzles) are disposed above and/or below the wash zone. The spray arms are configured to spray liquid toward the wash zone <NUM>. In a typical machine, both a wash spray arm 23a and a rinse spray arm 23b may be provided, with the wash spray arm fed by a pump <NUM> (<FIG>) that recirculates liquid from a collection sump or tank <NUM> below the wash zone, and the rinse spray arm fed by a pump (or line pressure) that delivers hot water from a hot water booster <NUM>. The arms may, for example, be rotating arms and/or fixed arms. Upper and lower sets of arms may be implemented.

Per <FIG>, a multi-sided hood assembly <NUM> includes movable front <NUM>, left <NUM>, right <NUM> and top <NUM> wall sections (e.g., forming a box-like hood structure that is open at the bottom) and the hood assembly may or may not have a moving back wall section <NUM>. The wall sections move together as a unit, such that the multi-sided hood assembly is movable (per arrow <NUM>) between a lowered closed position (e.g., per <FIG>) for washing and a raised open position (e.g., per <FIG>) for inlet and outlet of wares. When the multi-sided hood assembly is in the closed position, the hood assembly closes the front <NUM>, left <NUM> and right <NUM> access openings so that cleaning sprays within the chamber will be contained during ware cleaning. When the multi-sided hood assembly is in the open position, the front <NUM>, left <NUM> and right <NUM> access openings are open as shown in <FIG> to permit access to the wash zone for inlet and egress of wares. A pivot handle <NUM> may be provided to facilitate operator movement of the hood assembly <NUM>.

A stationary chamber rear wall <NUM> is disposed at the back side of the wash chamber and, in embodiments in which the hood assembly includes a rear wall section <NUM>, the wall <NUM> is at least partly behind the wall section <NUM> when the hood is closed. The rear wall <NUM> includes an outlet opening <NUM>, and in embodiments including the rear wall section <NUM>, the rear wall section <NUM> may include a cutout so as to avoid blocking the opening <NUM> when the hood is closed. The outlet opening <NUM> is fluidly connected with a vapor extraction unit <NUM> (<FIG>) at a back side of the rear wall <NUM>. The vapor extraction unit <NUM> includes an enclosure <NUM> with a condenser <NUM>, including a condenser coil, therein.

Per <FIG>, incoming cold water to the machine from a cold water line input <NUM> (e.g., controlled by a solenoid valve 90a along the line) passes through the condenser <NUM>. An enclosure outlet <NUM> (<FIG>) to surrounding ambient environment is also provided, here at the top of the enclosure. At least one air mover <NUM> (e.g., here two side-by-side axial fans 62a) are provided for moving hot water vapor from the chamber <NUM> into the vapor extraction unit <NUM> over the condenser <NUM> and then to ambient through the enclosure outlet <NUM>. Here, the axial fans <NUM> are mounted over the enclosure outlet <NUM>. Other types of air movers (e.g., other fan types or blowers) could be used to move the air, and the position of such air movers could vary.

A machine controller <NUM> (<FIG>) is provided for controlling ware cleaning cycles of the machine, where the cycles include both a wash operation and then a rinse operation. As used herein, the term controller is intended to broadly encompass any circuit (e.g., solid state, application specific integrated circuit (ASIC), an electronic circuit, a combinational logic circuit, a field programmable gate array (FPGA)), processor(s) (e.g., shared, dedicated, or group - including hardware or software that executes code), software, firmware and/or other components, or a combination of some or all of the above, that carries out the control functions of the machine or the control functions of any component thereof.

The controller <NUM> is configured to operate the water vapor extraction unit <NUM> by controlling each of (i) water flow through the condenser <NUM> (e.g., by opening solenoid valve 90a, or alternatively operating a pump or other flow control device) and (ii) operation of the air mover(s) (e.g., by connecting power to the fan motor) such that, at least after the rinse operation of the ware cleaning operation is completed, hot water vapor is pulled from the chamber through the vapor extraction unit while cold water flows through the condenser <NUM>. This process results in condensation of water vapor from the moist air, such that the air that passes to the enclosure outlet <NUM> is not excessively hot and/or moist.

Per <FIG>, the hot water vapor extraction unit <NUM> includes an internal water flow path for condensed water to flow from the unit back into the chamber. The illustrated water flow path passes through the outlet opening to reach the chamber (e.g., the bottom wall 64a of the enclosure housing <NUM> is angled to direct falling condensate back through the opening <NUM>). Per <FIG>, in the illustrated embodiment, the enclosure is formed in part by a secondary housing <NUM> and in part by the rear wall <NUM> of the machine housing, wherein the secondary housing <NUM> is mounted to the back side of the rear wall, with a gasket <NUM> along at least a majority of the perimeter of the housing to wall interface for sealing.

Per <FIG>, the outlet opening <NUM> is located on a lower portion <NUM> of the rear wall (e.g., the lower <NUM>/<NUM> of the portion of the rear wall aligned with the chamber <NUM>, or the lower <NUM>/<NUM> or the lower <NUM>/<NUM>). During operation of the fans <NUM>, hot water vapor (indicated by arrows <NUM> in <FIG>) is drawn from a lower portion of the chamber, while make-up air <NUM> enters the chamber by passing under the bottom of the front, left and/or right wall sections of the multi-sided hood assembly (e.g., see <FIG>). With this arrangement, hot water vapor is also captured and maintained within an upper portion <NUM> of the multi-sided hood assembly during operation of the water vapor extraction unit, thereby retaining a substantial portion of the desirable heat energy within the machine from cleaning cycle to cleaning cycle. Moreover, the volume of air drawn through the vapor extraction unit after the rinse operation of a cycle may be set to help assure that moist hot vapors are retained in the upper portion <NUM> of the hood assembly (e.g., by drawing a volume of air that is less than the volume within the hood assembly, such as drawing a volume that is less than <NUM>% of the overall hood volume, or less than <NUM>% of the overall hood volume or less than <NUM>% of the overall hood volume).

In some embodiments, the hood assembly <NUM> could be raised slightly (either manually or automatically by the controller) at the end of the rinse operation (as suggested by the hood assembly position in <FIG>) in order to enhance in-flow of make-up air.

In one embodiment, the controller <NUM> is configured such that, upon completion of the rinse operation of a ware cleaning operation, the vapor extraction unit is operated for a set period of time (e.g., between <NUM> seconds and <NUM> seconds). The controller <NUM> is also configured to (i) initiate an end of cycle alert (e.g., a visible alert such as a light or indication on a machine interface <NUM> and/or an audible alert) only after operation of the vapor extraction unit is completed and/or (ii) lock the hood assembly down in the closed state until operation of the vapor extraction unit is completed. With respect to such a hood lock down, per <FIG>, a powered latch mechanism <NUM> (e.g., solenoid or motor operated) is movable between a hood latch state for holding the multi-sided hood assembly in the closed position and a hood unlatch state (shown in <FIG>) that permits the multi-sided hood assembly to be moved to the open position. The ware cleaning cycle ends after the set time period and the controller <NUM> switches the powered latch mechanism to the hood unlatch state. In one embodiment, for the purpose of the lock down, the controller <NUM> is configured to maintain the powered latch mechanism <NUM> in the hood latch state during operation of the vapor extraction unit. In the illustrated embodiment, the latch mechanism <NUM> includes a pivoting latch component <NUM> that engages some part of the hood assembly (e.g., the top rear edge of the hood assembly or a bracket as the rear of the the hood assembly) when rotated in the direction of arrow <NUM> for the purpose of the latching.

As best seen in <FIG>, the condenser <NUM> is fluidly connected to receive incoming water from the cold water input <NUM> of the machine (e.g., under control of valve 90a) and to then deliver the incoming water (via path 90b) to a heat exchanger <NUM> (e.g., with counterflow coil) that exchanges heat between the incoming water and water flowing to drain along a drain water flow path <NUM> from the chamber. After passing through the heat exchanger <NUM>, the incoming water is delivered into a hot water booster <NUM> of the machine, which feeds the rinse arm(s) 23b. A hot water input <NUM> is connected to deliver incoming water (e.g., under control of solenoid valve 93a) to the sump/tank <NUM> of the chamber.

The described system extracts water vapor at the end of each cycle, which condenses the water, before the chamber door hood is opened. This is achieved by drawing air from the lower portion of the chamber and having it pass over the condenser (e.g., including copper coil). The condenser has the cold incoming water running through it. The energy from the hot water vapor is transferred to the cold water running through the copper coil causing the water vapor to lose temperature and condensate. The condenser may use a cross flow heat exchange method. In one example, the water is primarily running horizontally through the coil, moving up within the enclosure only after a number of horizontal passes. The hot water vapor travels vertically up through the enclosure until it finally condensates. The cold water enters the bottom of the condenser and steadily increases temperatures until it finally exits at the top.

Thus, the system reduces hot moist vapor exit upon door opening, improving the operator comfort and experience, as well as reducing room conditioning requirements. The water temperature of incoming water is also increased.

Per the illustrated embodiment, the system may function with a fully enclosed hood. With the fully enclosed hood, the goal is to maintain some hot water vapor inside the hood and only eliminate enough vapor so that it is not a problem for the operator. By keeping the hot water vapor inside the upper part of the fully enclosed hood, energy is maintained inside the machine and can be used for the next cycle. Removing primarily the vapor from the lower portion of the hood achieves this result. The positioning of the opening <NUM> to the unit <NUM>, along with the CFM of the <NUM> axial fans, works together to allow the inside of the chamber to maintain the high-water vapor temperature while still eliminating the vapor that might typically escape when the door is opened at the end of a cycle.

It is to be clearly understood that the above description is intended by way of illustration and example only, is not intended to be taken by way of limitation, and that other changes and modifications are possible. For example, a controllable damper could be provided at or along the outlet <NUM>, enabling a closed flow path during wash and rinse operations of a cleaning cycle, and then opening the flow path for the vapor extraction operation of the cycle.

Moreover, in an alternative embodiment, as shown in <FIG>, both an air extraction unit <NUM> and an air intake unit <NUM> are provided at the back side of the warewash machine <NUM>, rearward of the chamber <NUM> and the rear wall <NUM>. Although only parts of the machine <NUM> are shown in the drawings, it is understood that machine <NUM> is comparable to machine <NUM> in terms of overall configuration (e.g., with movable hood and wash and rinse systems and user interface as described above). In <FIG>, the air extraction unit <NUM> and air intake unit <NUM> are formed with a combined housing or enclosure <NUM>, with associated gasket <NUM>, which housing <NUM> at least in part defines an extraction compartment <NUM> and an intake compartment <NUM>. The compartments may be separated from each other by an internal enclosure wall <NUM> (e.g., creating two distinct flow paths that are substantially sealed from each other). Here, the compartments <NUM> and <NUM> are also formed in part by the back side of the warewash machine, as above.

The two units <NUM> and <NUM> form part of an air exchange system <NUM> that includes the extraction compartment <NUM> and the air intake compartment <NUM>. Compartment <NUM> includes a condenser <NUM> therein, wherein incoming water to the machine from a cold water input passes through the condenser <NUM> (in a manner similar to that described above for machine <NUM>). The air outlet <NUM> of compartment <NUM> leads to a surrounding ambient environment and one or more axial fans or other air mover <NUM> associated with the extraction compartment <NUM> and selectively controllable (e.g., by controller <NUM>) for moving hot water vapor from the chamber <NUM>, into the compartment <NUM>, over the condenser <NUM> and then out of the air outlet <NUM> (e.g., per flow <NUM> in <FIG>). The intake compartment <NUM> includes at a least one heater <NUM> therein and an air inlet <NUM> from the surrounding ambient environment, with one or more axial fans or other air mover <NUM> associated with the intake compartment <NUM> and selectively controllable (e.g., by controller <NUM>) for moving ambient air into the air inlet, past the heater(s) <NUM> to be heated and then into the chamber <NUM> (e.g., per flow <NUM> in <FIG>).

The machine controller <NUM> may be configured with various user selectable cleaning cycles, one or more of which involve operation of both the extraction unit <NUM> and the intake unit <NUM>. By way of example, the controller <NUM> is configured to carry out a ware cleaning cycle that includes a wash operation and a rinse operation, with the controller further configured to operate the air exchange system <NUM> so as to (a) carry out an extraction operation that involves controlling each of (i) water flow through the condenser <NUM> and (ii) operation of the air mover <NUM> such that, at least after the rinse operation of the ware cleaning cycle is completed, hot water vapor is pulled from the chamber through the compartment <NUM> (over/past the condenser <NUM>) and expelled from the air outlet <NUM> while water flows through the condenser <NUM>; and (b) carry out a drying operation that involves controlling each of (i) energization of the heater <NUM> and (ii) operation of the air mover <NUM> such that, at least after the extraction operation of the ware cleaning cycle is completed, ambient air is pulled from through the air inlet <NUM> from the surrounding ambient environment and passed through the compartment <NUM> (over/past the heater <NUM>) and to the chamber while the heater <NUM> is energized to heat the incoming air. Step (a) above represents a moisture extraction and heat recovery step of the cycle. Step (b) represents a drying step that may useful for certain ware types that tend to dry less efficiently.

In one example, the controller <NUM> is configured such that the drying operation occurs only after the air mover <NUM> is turned off to complete the extraction operation (i.e., no time overlap in air flows as between the extraction operation and the drying operation). Where a temperature sensor <NUM> is associated with the chamber <NUM>, the controller <NUM> may also be configured such that, during the drying operation, energization of the heater <NUM> is controlled such that a temperature within the chamber <NUM> as sensed by the temperature sensor <NUM> does not exceed a maximum threshold. For example, the heater <NUM> could be deenergized when a set temperature (Tset) is reached and reenergized at a lower detected temperature (Tset - <NUM>° F (<NUM>)). In other examples, a more refined approach may be taken (e.g., varying the energization level of the heaters and/or turning off less than all heaters when more than one heater is present).

Claim 1:
A warewash machine (<NUM>) comprising:
a housing (<NUM>) that at least in part defines a chamber with a wash zone, the chamber having front, left and right access openings;
at least one spray arm (23a) disposed above or below the wash zone, the spray arm (23a) configured to spray liquid toward the wash zone; and
a multi-sided hood assembly (<NUM>) including movable front, rear, left, right and top wall sections, the multi-sided hood assembly (<NUM>) movable between a lowered and closed position for washing and a raised and open position for inlet and outlet of wares, wherein in the raised and open position each of the front, rear, left, right and top wall sections is raised to form a space to retain hot water vapor inside the multi-sided hood assembly (<NUM>);
a stationary chamber rear wall (<NUM>), the stationary chamber rear wall (<NUM>) including at least one air exchange opening;
an air exchange system (<NUM>) located rearwardly of the stationary chamber rear wall (<NUM>), the at least one air exchange opening fluidly connected with the air exchange system, the air exchange system (<NUM>) including at least one secondary housing (<NUM>) defining, at least in part, a first compartment (<NUM>) and a second compartment (<NUM>);
wherein the first compartment (<NUM>) includes a condenser (<NUM>) therein, wherein incoming water to the machine from a cold water input passes through the condenser (<NUM>), wherein the first compartment (<NUM>) includes an air outlet to a surrounding ambient environment, a first air mover associated with the first compartment (<NUM>) and selectively controllable for moving hot water vapor from the chamber, into the first compartment (<NUM>), over the condenser (<NUM>) and out of the air outlet;
wherein the second compartment (<NUM>) includes at a least one heater (<NUM>) therein and an air inlet from the surrounding ambient environment, a second air mover associated with the second compartment (<NUM>) and selectively controllable for moving ambient air into the air inlet, past the heater (<NUM>) to be heated and into the chamber.