Patent Description:
It is known from prior art that in grocery stores, supermarkets etc. and for institutional catering services, for example for schools, canteens, cafeterias, temperature controlled cabinets for cool temperatures i.e. temperatures typically below +<NUM> are employed for products, such as food stuffs, beverages and like that must be kept in cooled temperatures and to allow users or customers to access groceries and other refrigerated or frozen items from the cabinet. These cabinets typically comprise a frame structure; supporting, top, bottom and wall structures with at least one door or without the doors with at least one partially open wall for customers to access the products. The frame structure surrounds at least one product space, which comprises shelves and/or other structures for the refrigerated or frozen products. It is known from prior art that as part of the bottom structure a base structure forming a reservoir is used. The reservoir is used to collect any condensate moisture controllably and typically provided with drainage means for removing the condensate moisture. The drainage means typically comprise piping for removing the collected condensate moisture from the reservoir. It is also known to locate the reservoir for collecting the condensate moisture as a separate structure from the cabinet in space left between the floor of the room, in which the cabinet is located, and the bottom wall of the cabinet. It is known from the prior art vacuum drainage systems are used as drainage means for removing the condensate moisture.

In international patent application publication <CIT> is disclosed a system for accumulation and evacuation of defrosting condensation water from a refrigeration and cooling unit under, in which each of water evacuation units includes a docking station and a water collection tray to be slidably provided within the docking station, whereby each unit is custom made to fit between the refrigeration unit and a floor where the refrigeration unit is placed, and whereby which docking station includes upwardly protruding guide members and end stoppers for guiding and positioning of the tray within the docking station, at the end of the docking station, between the end stoppers, is provided a suction pipe connection to be sealingly connected at its outer end to vertical piping of the system.

In <CIT> is disclosed a buffer box for use in a vacuum collection system having a drainage pipe maintained under partial vacuum pressure, a suction valve for selectively controlling access to the drainage pipe, and a collection pipe having an inlet adapted to collect waste fluid from a waste fluid source. The buffer box comprises a base, a side wall extending upwardly from the base, a cover attached to the side wall so that an interior of the base, side wall, and cover define a reservoir, an inlet fluidly communicating between the collection pipe and the reservoir, an outlet formed in the side wall adapted to fluidly communicate with the suction valve, and an air intake orifice integrally provided with the buffer box and fluidly communicating between the reservoir and atmosphere, wherein waste fluid collecting in the reservoir is transported to the drainage pipe when the suction valve actuates to an open position. By this buffer box effective transport of condensation water in the vacuum drainage system is accomplished. This buffer box is designed to contain and transport a measured amount of water using a pneumatic head pressure sensing port. The pressure head sensing port is connected to a pneumatic activator the that connects the vacuum source to a discharge valve that opens to remove the contents of the buffer box.

In patent publication <CIT> is disclosed a vacuum drainage system for collecting waste fluid from a source, the vacuum drainage system comprising a buffer positioned to receive waste fluid from the source, the buffer having an inlet opening and an air intake opening, a vertical riser having a lower riser section in fluid communication with the buffer and an upper riser section, a normally closed interface valve disposed between the upper and lower riser sections, the interface valve operable to open in response to a fluid level in the buffer, a main drainage pipe in fluid communication with the upper riser section, the main drainage pipe being maintained under vacuum, and an aeration point formed in the lower section of the riser at a height above a low point of the riser, the aeration point establishing fluid communication between an interior of the riser and atmosphere so that, when the interface valve is open, air at atmospheric pressure is pulled through the aeration point and into the lower riser section.

In patent application publication <CIT> is disclosed an accumulator for a vacuum drainage system comprising: a body having a bottom wall, sidewalls and top wall, the bottom wall, sidewalls and top walls cooperating to define a reservoir within the body; a first inlet port and a first outlet port provided toward a first end of the body; a second inlet port and a second outlet port provided toward a second end of the body; and wherein the first and second inlet ports respectively define with the body first and second inlet openings into the reservoir, and the first and second outlet ports respectively define with the body first and second outlet openings from the reservoir.

During the recent times due to redesigns of the temperature controlled cabinet for low temperatures height of the space left between the floor of the room, in which the temperature controlled cabinet for low temperatures is located, and the bottom wall of the cabinet has decreased and thus there exist a need to redesign the reservoirs for collecting the condensate moisture with decreased height as in some instances a recess in the floor to accommodate the reservoir has been needed to provide or in some other instances a supplementary pumping system to collect the condensate and transport it to the reservoir, now located elsewhere for example located on top of the cabinet, has been needed to be provided in order to interface with the vacuum drainage system.

The decreased height of the buffer box may cause a disadvantage due to the air accumulation over the top of the fluid, of which most will simply travel over the top of the fluid on its way to the buffer box outlet to the riser of the vacuum drainage system. This might further cause difficulties in functioning of the vacuum drainage system, especially in removal functions of the buffer box.

One object of the invention is to eliminate or at least minimize the above problems and disadvantages of prior art buffer boxes for vacuum drainage systems.

A particular object of the invention is to create a buffer box with decreased height, in which the disadvantages and problems relating to the air accumulation over the top of the fluid are eliminated or at least minimized.

To achieve the above-mentioned objects and those which come out later, the a vacuum drainage system according to the invention is characterized by what is presented in the characterizing part of claim <NUM>. Advantageous features of the invention are defined in dependent claims.

According to the invention the buffer box of a vacuum drainage system comprising the buffer box comprising as an outer frame structure side walls, end walls, a top wall and a bottom wall and further comprising an inlet and a buffer box outlet, which vacuum drainage system comprises a vacuum drainage piping, at least one collection branch connected to the vacuum drainage system and to the buffer box outlet of the buffer box, wherein each of the collection branches comprises a suction valve, a pump connected to the vacuum drainage piping and configured to create negative pressure in the vacuum drainage piping, wherein the buffer box comprises a main compartment and a suction compartment with a suction outlet, wherein between the main compartment and the suction compartment a baffle is located, wherein the baffle extends from the top wall towards the bottom wall and is located at a distance from the bottom wall such that a baffle opening is formed between the main compartment and the suction compartment and wherein the baffle is configured to prevent the air on top of the liquid in the main compartment to enter the suction compartment. According to an advantageous aspect of the invention the vacuum drainage system comprises a storage tank and the vacuum drainage piping is connected to the storage tank or according to another advantageous aspect the vacuum drainage system comprises a pump and the vacuum drainage piping is via the pump directly connected to a vacuum transport plumbing or directly to a drain to a sewer.

According to an advantageous feature of the invention the buffer box is low, wherein height of the buffer box is <NUM> - <NUM> and the height of the buffer box is sufficient to receive drainage as positioned underneath the temperature controlled cabinet, typically <NUM> or less, as dependent on the clearance from ground level to the drain of the temperature controlled cabinet.

According to an advantageous feature of the invention the suction compartment comprises a pre-aeration port configured to allow a measured amount of air to the buffer box outlet prior to liquid from the main compartment of the buffer box.

According to an advantageous feature of the invention the suction compartment is configured to accelerate emptying of the main compartment from therein collected liquid by removing air from the suction compartment through the pre-aeration port by creating a vacuum in the suction compartment by providing a suction force along the baffle opening from the main compartment to the suction compartment.

According to an advantageous feature of the invention area of the baffle opening exists in direct proportion to the flow area of the buffer box outlet and width of the buffer box such, that the area of the baffle opening is at a minimum <NUM>:<NUM> proportion to the buffer box outlet. By this, the possible restriction of the flow is advantageously avoided.

According to an advantageous feature of the invention the buffer box comprises a pneumatic head pressure chamber. According to an advantageous aspect the flow from the main compartment to the suction compartment in the buffer box is configured to keep the pneumatic head pressure chamber free of debris by designing the height of the baffle opening as determined by the area of flow of the outlet and width of the buffer box is equivalent to the set height of the opening of the pneumatic head pressure chamber. By this relationship is advantageously ensured that as the fluid flows under the baffle, the velocity of the flow that is produced scours the opening of the pneumatic pressure chamber which is correspondingly set.

According to an advantageous feature the buffer box is configured to withstand sudden and sustained surge flows proportional to the buffer box capacity and outlet flow area. In one embodiment of the invention with a nominal holding capacity of up to <NUM>, the buffer box is configured to withstand a sudden and sustained surge flow of up to <NUM> LPM without overflowing.

According to an advantageous feature of the invention the buffer box further comprises a suction chamber vent. The vent allows pressure equilibrium during the filling of the box with collected fluid between the main chamber and the suction compartment and subsequently serves to feed air to the pre-aeration port during the evacuation of the suction compartment.

According to an advantageous feature of the invention the buffer box further comprises a head pressure port.

According to an advantageous aspect of the invention the vacuum drainage system comprises a pneumatically activated activator configured to be used with the buffer box. The pneumatically activated activator comprises an activation head of less than <NUM>, advantageously of <NUM> - <NUM> nominally.

According to an advantageous aspect of the invention the vacuum drainage system comprises a pre-aeration port configured to allow a measured amount of air into the outlet prior to the water from the main compartment of the buffer box. This aeration rapidly clears standing water from the horizontally from the outlet extending pipe part of the collection branch that connects the buffer box to the vacuum drainage piping. This horizontal pipe part is typically up to <NUM> meter in length.

According to an advantageous aspect of the invention the buffer box of the vacuum drainage system comprises a suction compartment that accelerates the emptying of the main compartment of the buffer box to efficiently remove surges of water from events such as temperature controlled cabinet washdowns as the air is removed from the suction compartment through the pre-aeration port, a vacuum is created in the suction compartment, which vacuum creates a suction force along the baffle opening from the main compartment to the suction compartment. This produces an accelerated emptying of the main compartment with a reduced air flow into the vacuum drainage system. The flow through the buffer box keeps also the sensing chamber i.e., the pneumatic head pressure chamber free of debris and helps to increase velocity of the flow under the baffle i.e. in the baffle opening to keep the buffer box clean and clear of soft debris.

According to an advantageous aspect of the invention in the vacuum drainage system as the air is removed from the suction compartment through the pre-aeration port, a vacuum is created in the suction compartment. This vacuum creates a suction force along the baffle opening from the main compartment to the suction compartment. This produces an accelerated emptying of the main compartment with a reduced air flow into the vacuum drainage system. This provides for accelerated emptying the water with the reduced air flow into the vacuum drainage system and thus the buffer box is provided to withstand sudden and sustained surge flows of up to <NUM> LPM without overflowing. Thus, the configuration of the buffer box also allows for a high-flow rinse area around the opening of the pneumatic head pressure chamber and across the bottom of the buffer box. This flow of water across the bottom of the buffer box provides a rinsing action across the bottom of the pneumatic sensing column.

The invention is especially suitable to be used in connection with temperature controlled cabinets for cool temperatures as a condensate collection system. This low-profile sensing and control approach is also adaptable to other collection products such as floor and shower drains which are utilized as gray water collection points for vacuum waste drainage systems.

The buffer box of a vacuum drainage system according to the invention and its advantageous features provides for a reduction in maintenance to the rinsing effect of the pneumatic sensing column. The buffer box also reduces or even eliminates the jelly buildup around the pneumatic pressure sensing port.

Aspects of the invention, however, together with additional objects and advantages thereof, will be best understood from the following description of some example embodiments when read in connection with the accompanying drawings and in the following the invention is described in more detail referring to the accompanying drawing, in which.

During the course of this description like numbers and signs will be used to identify like elements according to the different views which illustrate the invention. Repetition of some reference signs may have been omitted in the figures for clarity reasons.

In <FIG> is shown an example of a vacuum drainage system <NUM> comprising a storage tank <NUM> and to the storage tank <NUM> connected a vacuum drainage piping <NUM>, which is connected to at least one, in the example of the <FIG> two, collection branch <NUM>, a pump <NUM> connected by the vacuum drainage piping <NUM> to the storage tank <NUM>. In the example of the <FIG> the vacuum drainage system <NUM> comprises the storage tank <NUM> and the vacuum drainage piping <NUM> is connected to the storage tank <NUM>, but alternatively the vacuum drainage system <NUM> may comprise a pump and the vacuum drainage piping <NUM> then is via the pump directly connected to a vacuum transport plumbing or directly to a drain to a sewer. Each of the collection branches <NUM> comprises a suction valve <NUM>, which connects the respective collection branch <NUM> to the vacuum drainage piping <NUM>. In normal operation stage the suction valves <NUM> are closed and the pump <NUM> creates negative pressure in the vacuum drainage piping <NUM>. The collection branch <NUM> is thus at one end connected to the vacuum drainage piping <NUM> by the suction valve <NUM> and at the other end connected to outlet <NUM> of a buffer box <NUM>. The buffer box <NUM> has an inlet <NUM> to which liquid, condensate from a temperature controlled cabinet for cool temperatures is directed. The vacuum drainage piping <NUM> also comprises a check valve <NUM> at a location before the vacuum drainage piping <NUM> connects to the storage tank <NUM>. The storage tank <NUM> also comprises a drain <NUM> used for periodic discharge to a sewer drain.

In <FIG> is shown an example of the buffer box <NUM>, comprising as an outer frame structure side walls <NUM>, <NUM>, end walls <NUM>, <NUM>, a top wall <NUM> and a bottom wall <NUM>. The top wall <NUM> with the side walls <NUM>, <NUM> and the end walls <NUM>, <NUM> is constructed to form a cover frame structure of the buffer box <NUM> and the bottom wall <NUM> forms a bottom frame structure of the buffer box <NUM>. The buffer box <NUM> comprises, as functional parts, a main compartment <NUM> and a suction compartment <NUM>. Between the main compartment <NUM> and the suction compartment <NUM>, as a dividing structure, a baffle <NUM> is located. The baffle <NUM> extends from the top wall <NUM> towards the bottom wall <NUM> but is located at a distance from the bottom wall <NUM> such that a baffle opening 15A is formed. Area of the baffle opening 15A exists in direct proportion to the flow area of the buffer box outlet <NUM> and width of the buffer box <NUM>, advantageously the area of the baffle opening 15A is advantageously at a minimum <NUM>:<NUM> proportion to the buffer box outlet <NUM>.

The buffer box <NUM> has at one end wall <NUM> an inlet <NUM> and at the other end wall <NUM> an outlet <NUM>. The buffer box <NUM> in this example also comprises an alternate inlet <NUM>, which also may function as vent and overflow. The alternate inlet <NUM> can be used for draining directly into the top of the buffer box <NUM> with the inlet <NUM> sealed, or it can be used in a plural configuration with drainage coming into both inlets simultaneously. The buffer box <NUM> also comprises a suction outlet <NUM> from the suction compartment <NUM> with a pre-aeration port <NUM>, a suction chamber vent <NUM>, a pneumatic head pressure chamber <NUM> and a head pressure port <NUM>. The suction outlet <NUM> comprises a suction outlet opening 16A whose gap is set marginally higher than the baffle opening 15A in order to allow any material that passes the baffle opening 15A to pass through the buffer box outlet <NUM> and into the vacuum collection branch <NUM>. Typically the suction outlet opening 16A is set slightly higher than the baffle opening 15A but advantageously is less than the minimum point of egress of the outlet <NUM>. For example, if any debris gets into the suction compartment <NUM>, it is passed through the suction outlet <NUM> and into the vacuum drainage piping <NUM>. Advantageously, the opening of the pressure chamber <NUM> and the baffle opening 15A are set substantially identically to ensure the scouring action of the flow for cleaning purposes and for continuation of the flow into the suction outlet <NUM> via its opening 16A which is advantageously nominally higher. The buffer box <NUM> is low and the height of the buffer box <NUM> is sufficient to receive drainage as positioned underneath the temperature controlled cabinet, typically <NUM> or less, as dependent on the clearance from ground level to the drain of the temperature controlled cabinet. The buffer box <NUM> may have a height of <NUM> - <NUM> i.e. the distance between the outer surface of the bottom wall <NUM> and the outer surface of the top wall <NUM> is advantageously <NUM> - <NUM>. The pre-aeration port <NUM> is configured to allow a measured amount of air to the outlet <NUM> prior to the water from the main compartment <NUM> of the buffer box <NUM>. This aeration rapidly clears standing water from the outlet <NUM> extending horizonal pipe part of the collection branch that connects the buffer box <NUM> to the vacuum drainage piping <NUM>. This horizontal pipe part extending from the outlet <NUM> is typically up to <NUM> meter in length.

The suction compartment <NUM> is configured to accelerate the emptying of the main compartment <NUM> of the buffer box <NUM> and to efficiently remove surges of water as the air is removed from the suction compartment <NUM> through the pre-aeration port <NUM>, a vacuum is created in the suction compartment <NUM>, which vacuum creates a suction force along the baffle opening 15A from the main compartment <NUM> to the suction compartment <NUM>. This produces an accelerated emptying of the main compartment <NUM> with a reduced air flow into the vacuum drainage system <NUM> as the baffle <NUM> prevents the air on top of the liquid to enter the suction compartment. The flow through the buffer box <NUM> keeps also the pneumatic head pressure chamber <NUM> i.e. the sensing chamber free of debris and helps to increase velocity of the flow under the baffle <NUM> i.e. in the baffle opening 15A to keep the buffer box <NUM> clean and clear of soft debris. The height of the baffle <NUM> as determined by the area of flow of the outlet <NUM> and width of the buffer box <NUM> is equivalent to the set height of the opening 19A of the pneumatic head pressure chamber <NUM>. As the vacuum creates the suction force along the baffle opening 15A from the main compartment <NUM> to the suction compartment <NUM> and the accelerated emptying of the main compartment <NUM> with the reduced air flow into the vacuum drainage system <NUM> (<FIG>) is provided for the accelerated emptying of the water. The buffer box <NUM> is configured to withstand sudden and sustained surge flows proportional to the buffer box capacity and outlet flow area. In one example of the buffer box <NUM> with a nominal holding capacity of up to <NUM>, the buffer box <NUM> is configured to withstand a sudden and sustained surge flow of up to <NUM> LPM without overflowing. Thus, the configuration of the buffer box <NUM> allows for a high-flow rinse area around the opening of the pneumatic head pressure chamber <NUM> and across the inner surface of the bottom wall <NUM> of the buffer box <NUM>. This flow of water across the bottom of the buffer box <NUM> provides a rinsing action across the bottom of the pneumatic head pressure chamber <NUM>.

As shown in figures <NUM>-4C the vacuum drainage system <NUM> also comprises an activator <NUM> configured to control by means of operation of the suction valve <NUM> liquid level of the main compartment <NUM> of the buffer box <NUM>. The vacuum drainage system <NUM> is provided with a sensor <NUM> connected to the head pressure port <NUM> of the buffer box <NUM>. The sensor <NUM> monitors pressure level in the pneumatic head pressure chamber <NUM>. The liquid in the main compartment <NUM> of the buffer box <NUM> closes off the bottom end of the pneumatic head pressure chamber <NUM> as the buffer box <NUM> fills with liquid and at the same air is trapped and compressed. Thus, during the liquid level raising, the pressure of the trapped air increases in the pneumatic head pressure chamber <NUM> and based on measured pressure level the liquid level in the main compartment <NUM> of the buffer box <NUM> can be determined. The activator <NUM> is also connected by a suction and valve line <NUM> to the valve <NUM> of the vacuum drainage piping <NUM> via the respective connect line <NUM>. The valve <NUM> functions between open and closed positions by means of the negative pressure in the connect line <NUM> and in the vacuum drainage piping <NUM> when transported through the suction and valve line <NUM>. Thus, based on the setting of the activator <NUM>, when the set liquid level height is observed by the sensor <NUM>, the activator <NUM> allows negative pressure to flow to the valve <NUM> as the valve <NUM> is opened. The liquid is transported via the outlet of the buffer box <NUM> to the collection branch <NUM> and to the vacuum drainage piping <NUM>, when the liquid level in the main compartment of the buffer box <NUM> has reached the set liquid level by the sensor <NUM>. The activator <NUM> opens the valve <NUM> and keeps it in open position for a preset time period. When the valve <NUM> is in open position, the negative pressure effects on the liquid in the buffer box <NUM>. The atmospheric air over the liquid in the buffer box <NUM> creates a pressure difference via suction chamber vent <NUM> and pushes the liquid to the outlet <NUM> of the buffer box <NUM> and to the collection branch <NUM> and further to the vacuum drainage piping <NUM> and simultaneously the suction chamber vent <NUM>. At the same time, air flowing through the pre aeration vent <NUM> occupies the buffer box <NUM>. After a set time interval suction is closed by the valve <NUM>. The vacuum drainage piping <NUM> directs the liquid to the storage tank <NUM>, which is emptied at set time intervals via drain <NUM>. The vacuum drainage piping <NUM> also comprises a check calve <NUM> to prevent back flow.

Claim 1:
Vacuum drainage system (<NUM>), which vacuum drainage system (<NUM>) comprises
- a vacuum drainage piping (<NUM>),
- at least one collection branch (<NUM>) connected to the vacuum drainage piping (<NUM>) and to a buffer box outlet (<NUM>) of a respective buffer box (<NUM>),
wherein each of the collection branches (<NUM>) comprises a suction valve (<NUM>),
- the buffer box (<NUM>) comprising as an outer frame structure side walls (<NUM>, <NUM>), end walls (<NUM>, <NUM>), a top wall (<NUM>) and a bottom wall (<NUM>), and further comprising at least one inlet (<NUM>) and the buffer box outlet (<NUM>),
- a pump (<NUM>) connected to the vacuum drainage piping (<NUM>) and configured to create negative pressure in the vacuum drainage piping (<NUM>),
characterized in,
- that the buffer box (<NUM>) comprises at least two compartments, which comprise a main compartment (<NUM>) and a suction compartment (<NUM>) with a suction outlet (<NUM>),
- that between the main compartment (<NUM>) and the suction compartment (<NUM>) a baffle (<NUM>) is located,
- that the baffle (<NUM>) extends from the top wall (<NUM>) towards the bottom wall (<NUM>) and is located at a distance from the bottom wall (<NUM>) such that a baffle opening (15A) is formed between the main compartment (<NUM>) and the suction compartment (<NUM>),
- and that the baffle (<NUM>) is configured to prevent the air on top of the liquid in the main compartment (<NUM>) to enter the suction compartment (<NUM>).