US3565045A

US3565045A - Liquid handling and dispensing apparatus

Info

Publication number: US3565045A
Authority: US
Inventors: William C Knox Jr
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-06-02
Filing date: 1969-06-02
Publication date: 1971-02-23
Anticipated expiration: 1988-02-23

Abstract

A tank of the type including an entrapped air cushion and for receiving, heating and dispensing heated liquid is improved through the combination of two cooperating liquid carrying conduits enclosed within the tank. A first of such conduits provides for preheating of incoming liquid and discharge into a lower portion of the tank. The second conduit, which draws cooler liquid from the lower portion of the tank for discharge into a mixing chamber, includes a vent in its location in the upper portion of the tank to control the liquid level in the tank. The mixing chamber receives cooler liquid from the second conduit and communicates with the upper portion of the tank to receive heated liquid, discharging a mixture of the two through a liquid discharge means.

Description

United States Patent Inventor William C. Knox Jr.

46 Des Molnes Way South, Seattle, Wash. 98148 Appl. No. 835,292

Filed June 2, 1969 Patented Feb. 23, 1971 LIQUID HANDLING AND DISPENSING 3,503,384 3/1970 Matarazzo et al.

ABSTRACT: A tank of the type including an entrapped air cushion and for receiving, heating and dispensing heated liquid is improved through the combination of two cooperating liquid carrying conduits enclosed within the tank. A first of such conduits provides for preheating of incoming liquid and discharge into a lower portion of the tank. The second conduit, which draws cooler liquid from the lower portion of the tank for discharge into a mixing chamber, includes a vent in its location in the upper portion of the tank to control the liquid level in the tank. The mixing chamber receives cooler liquid from the second conduit and communicates with the upper portion of the tank to receive heated liquid, discharging a mixture of the two through a liquid discharge means.

g z ii PATENTEDFEBNIBYI 3.565045 I SHEET 2 OF 2 INVENTOR.

WILLIAM c. KNOXJR.

n-rTonNiV- uoum HANDLING AND DISPENSING APPARATUS The heating and dispensing of heated liquids, such as water, in certain types of vehicles and conveyances, for example, aircrafts, trains, boats, mobile homes, camping trailers, etc., present problems difierent from the performance of such functions within stationary heated enclosures such as buildings. Generally, such vehicles are designed to be compact and to make as efficient utilization of space as possible. When the combination of weight and space is important, as is the case in aircraft either in lavatories or for heating water for other purposes, apparatus to heat and dispense water preferably is very small and hence cannot store appreciable amounts of heated water. For example, such apparatus commonly in use in large jet passenger aircraft has a liquid storage capacity of no more than about a gallon. Such apparatus must have the capability of heating liquid rapidly yet of dispensing heated liquid at a temperature which is not too hot for reasonable passenger use. One example of such use is the rinsing of hands.

This type of apparatus must depend upon a larger liquid storage tank which supplies liquid. to the heating and dispensing unit as required. Frequently, such a tank and its supply passages will include or gather entrapped air. If introduced into a relatively small heating and dispensing apparatus such entrapped air can result in sputtering or spraying of the fluid discharged.

As a result of the small size of the apparatus to which the present invention relates, there is a danger of either Stratification of liquid at different temperatures or the flow of relatively cold inlet liquid directly to the means which is intended to discharge heated liquid. in some cases, excessively hot liquid, which has collected near the top of the unit,has been known to be discharged directly for use; In other cases, unheated liquid has been discharged directly.

Because the liquid heating and dispensing apparatus may be assembled in a vehicle which is parked at temperatures below the freezing point of the liquid retained in the apparatus, means must be provided to allow for expansion of frozen liquid.

It is a principal object of the present invention to provide an improved apparatus for heating and dispensing heated liquid of the type described above, which avoids stratification of heated liquid in the apparatus and avoids direct communication between means to discharge heated liquid and incoming cooler liquid which may include entrapped gases.

Another object is to provide such an apparatus with means to preheat incoming cooler liquid and to draw independently such preheated liquid introduced into the tank for mixture with heated liquid from the tank without drawing entrapped air carried by the incoming liquid.

Still another object is to avoid discharge from the tank of liquid at the highest temperature level in the tank.

These and other objects and advantages will be more fully understood from the following detailed description and the drawings all of which are intended to be representative of rather than limiting on the scope of the present invention In the drawings:

FIG. 1 is a partially sectional view of the improved liquid heating and dispensing apparatus according to a preferred form of the present invention;

FIG. 2 is a sectional view of the apparatus of FIG. 1 along line 2-2;

FIGS. 3, 4 and 5 are fragmentary sectional views of the first liquid carrying conduit including the pumping means,

The present invention relates to the type of liquid handling and dispensing apparatus described in copending application Ser. No. 681,031, now US. Pat. No. 3,447,560 filed Nov. 11, 1967 as a continuation of application Ser. No. 524, 194, filed Feb. I, 1966 and now abandoned. It has been recognized that the above objects, particularly with respect to efficiency of operation, preheating and avoidance of Stratification and of direct communication between inlet liquid and the discharge means can be accomplished as a significant improvement over prior apparatus. According to the present invention, this is done through the use, in combination, of two liquid carrying conduits both enclosed within the tank and only one of which communicates directly with incoming liquid.

A first liquid carrying conduit, which introduces liquid into the tank, preferably enters in the tank lower portion which is generally cooler. ln such an arrangement, it then passes in what might be considered to be a loop from the lower portion of the tank into the upper portion and then returns to the lower portion to discharge incoming, and at that point preheated, liquid generally at the lower wall of the tank. Such type of discharge avoids turbulent flow through the tank. It is important that the first liquid carrying conduit include in its location in the upper portion of the tank, either through the loop arrangement or upon entry in that area, a pumping means, such as an aspirator or venturi. Such pumping means and a cooperating port means draws heated liquid from the top of the tank into the first liquid carrying conduit to mix with and preheat the incoming liquid. In a preferred embodiment, the preheating process is a combination of two sources: a first is heat from liquid carried by the tank conducted through walls of the first liquid carrying conduit into the incoming liquid; a second and more important is the mixing as a result of operation of the pumping means of hotter liquid in the upper portion of the tank with the incoming liquid for subsequent discharge into the lower portion of the tank.

The second liquid carrying conduit has its inlet within the tank in the lower portion in order to draw cooler liquid for more efiicient use in mixing with hotter liquid in a final mixing chamber connected between the second liquid carrying conduit and a liquid discharge means. The second liquid carrying conduit also includes in its location in its upper portion of the tank a level control vent. Such vent establishes the minimum liquid level in the tank at a point above the port means cooperating with the pumping means of the first liquid carrying conduit to assure the availability of hot liquid for use in preheating incoming liquid.

Separation between the outlet of the first conduit and the inlet of the second conduit allows entrapped gases, such as air, from the incoming liquid, to rise in the tank. Such gases coilect at the top, allowing for more uniform control and bleeding of such entrapped air and avoiding sputtering or spraying of the discharged liquid.

Referring to FIGS. 1 and 2, the apparatus of the present invention includes a tank shown generally at 10 having an upper portion 11 enclosed by a wall 12 and a lower portion 13 enclosed by a wall 14. The upper portion has an upper wall 16 and the lower portion has a lower wall 18 generally defining the top and bottom, respectively, of the tank. However, for convenience of manufacture or installation, the tank shell can assume a variety of shapes.

Mounted within the tank are first liquid carrying conduit 20 and second liquid carrying conduit 22. The first conduit enters through a wall of the tank, preferably in the lower portion, for example, through lower wall 18 and, in FIGS. 1 and 2, fitting 21. In the embodiment shown in FIG. 1, it. then extends in a loop from the lower portion into the upper portion returning to the lower portion for discharge through first conduit outlet 24. In order to avoid turbulent flow within the tank as a result of the incoming liquid, the first conduit outlet 24 directs the incoming liquid generally toward or along lower wall-18.

The first conduit 20 includes in its location in the upper portion of the tank first conduit pumping means 26 which cooperates with first conduit port means 28 to draw heated liquid from the upper portion of the tank for mixing with and preheating the incoming liquid. The first conduit can enter the tank directly into the upper portion thereby relying for preheating on the pumping means and on conduction through the conduit wall as it passes to the lower portion. Such preheating assists in avoiding stratification within the tank and also makes more efficient use of the heated liquid generated in the tank. It is preferable that the walls of the first conduit are of a heat conducting material such as a metal. In such a case, preheating of the incoming liquid as a result of mixing through the pumping means and the cooperating first conduit port means is enhanced through conduction of heat from heated liquid in the tank through walls of the first conduit to the incoming liquid. Thus, incoming liquid first discharged into the interior of tank from first conduit is at a temperature substantially greater than that of the liquid first entering the first liquid carrying conduit 20. By increasing the incoming liquid temperature closer to the final desired temperature, the possibility of stratification in the tank is reduced and more uniform heating can take place.

The second liquid carrying conduit 22, like the first liquid carrying conduit 20, is enclosed within tank 10. The second conduit inlet 30 is located in the lower portion of the tank to draw the preheated yet cooler liquid from the tank for subsequent mixing with heated liquid in final mixing chamber 32. Second conduit inlet 30 is spaced apart from first conduit outlet 24 to allow entrapped gases such as air in incoming liquid to rise through the tank toward the top and to allow some mixing of the incoming liquid with liquid already in the tank. In this way, the liquid first introduced into the tank does not flow directly into the second conduit thus reducing the possibility of direct flow between the liquid inlet 34 and the liquid discharge means 36. To enhance circulation in the bottom of the tank and to allow for complete tank drainage, if such is desired, an auxiliary circulation and drain port 31 can be provided. Such port 31 can be placed through fitting 21 into communication with conduit 20 and positioned to direct liquid along the lower wall 18.

The second conduit extends from the lower portion of the tank into the upper portion of the tank discharging at 38 into final mixing chamber 32. The second conduit includes a liquid minimum level control vent 40 located in the upper portion of the tank at a point vertically higher than the first conduit port means 28 to maintain the level of liquid in the tank above the level of the first conduit port means 28 as will be explained in detail later. In the embodiment shown in FIG. 1, second conduit 22 describes a loop 29 which functions as a hydraulic balance on first filling of the tank.

The second conduit can include one or more second conduit port means 42 to act as does the first conduit port means to preheat still further the liquid drawn from the lower portion of the tank for mixing in the final mixing chamber.

Final mixing chamber 32 receives the now preheated liquid generally from the lower portion of the tank from the second conduit through second conduit discharge 38. In addition, final mixing chamber 32 includes a heated liquid inlet port 44 as the principal means for drawing heated liquid from the interior of the upper portion of tank 12. In the preferred form of the present invention shown in FIG. 1, heated liquid inlet port 44 is vertically lower than first conduit port means 28. This arrangement allows the first conduit port means 28 to draw off for preheating the hottest water which will normally collect near the liquid surface 46, the interface between air cushion 48 and the liquid in the tank. Generation of the air cushion will be described later. Through this arrangement, the hottest water in the tank cannot communicate directly with the liquid discharge means 36.

The size of the first and second conduits, their inlets and outlets, as well as the size of the first and second conduit port means such as 28 and 42 and heated liquid inlet port 44 of final mixing chamber 32 can be selected and coordinated in size and location within the scope of the present invention to deliver heated liquid at a desired temperature partly as a function of incoming liquid temperature and pressure.

As shown by FIGS. 1 and 2, included within tank 10 generally in the lower portion is a heating means 50 such as heaters of the electrical resistance type commercially available. Also located within the tank generally in the lower portion is a temperature sensing means 52 such as a commercially available adjustable thermostat. Because of the relative small size of tank 10, it is preferable that the temperature sensing means 52 be of a type which senses and preferably integrates temperature over a substantial portion of the tank rather than at a single point. Thus, thermostat 52 is shown to extend approximately one-third of the distance between lower wall 18 and upper wall 16. Greater extension could be made if the vibration of such a temperature sensing means would not present problems in vehicular operation.

Heating means 50 and temperature sensing means 52 are connected together and to a source of electrical power (not shown) through electrical conductors 54 so that the temperature sensing means 52 controls the operation of heating means 50 as a function of the temperature of the liquid in the tank 10 in a manner which is well known in the art. An overtemperature sensing device (not shown) can be mounted in the upper portion of the tank to sense temperature at the top of the tank and to shut off power to heating means 50 in the event of failure of temperature sensing means 52.

Because the apparatus of the present invention operates with an air cushion 48 adjacent upper wall 16 of upper portion 11, it is preferred to include a pressure relief valve through a wall of the tank. One arrangement, shown in FIG. 1 includes pressure relief valve 56 through the upper wall 16 of the tank. However, such a pressure relief valve could be mounted elsewhere through the wall of the tank if desired and convenient.

When the apparatus of the present invention is mounted for operation, liquid inlet means 34 is connected to a source of liquid, such as water, (not shown). Also, liquid discharge means 36 is connected with a valve means (not shown) such as the faucet of a lavatory wash basin or other liquid dispensing unit. Thus cooperating with the apparatus of the present invention are valve means (not shown) which control liquid inlet and discharge flow to and from the apparatus.

As shown in FIG. 1, there can be included in the apparatus of the present invention an electrical power control means such as button 58 and control switch 59 which initiates operation of the heating means 50 and temperature sensing means 52.

Although tank 10 is shown in FIG. 1 substantially as rectangular, it should be understood that tank 10 can be provided in a variety of shapes and sizes desired for the particular application provided the relationships between the components defined by the present invention are maintained. One typical size in the configuration shown in FIG. 1 has a liquid capacity of about 3-5 pints.

When placed in operation, tank 10 is connected with means to introduce liquid into the tank and means to discharge liquid from the tank through inlet 34 and discharge means 36, respectively. Then the valve cooperating with liquid discharge means 36 is opened. Liquid, such as water, begins to fill the tank expelling air through the liquid discharge means until the level of liquid in the tank covers heated liquid inlet port 44. At that point at which liquid begins to flow through the liquid discharge means 36, the valve cooperating with such discharge means generally is closed, either automatically as with a float-type valve or manually. Also, in the embodiment of FIG. 1, liquid traverses the hydraulic balancing loop 29. If such valve is not closed, partial pressurization of air entrapped in the upper portion of the tank occurs until the liquid level reaches liquid level control vent 40 at which time full pressurization of entrapped air occurs. Normally, however, when liquid begins to flow through the liquid discharge means, the valve associated with that means is closed to control more accurately the level of liquid in the tank and the amount of air cushion entrapped in the upper portion adjacent the wall 16.

Incoming liquid continues to fill the tank until it has compressed the air in the upper portion of the tank to a point at which the pressure exerted by the air being compressed and the pressure exerted by the incoming liquid are equal or at equilibrium. In one typical example, such pressure is at about 15 psi. and the flow rate is at about 1 gallon per minute.

' Thus there is established a liquid surface 46 as the interface between air cushion 48 and the liquid in the tank. The level of such a surface is controlled by the position of liquid minimum level control vent 40 which will draw off air from the air cushion in the event the level 46 falls below the level of vent 40. However, the level of liquid surface 46 can be above control vent 40, dependent upon the pressure equilibrium between the liquid and the air in the air'cushion. Thus accord ing to the present invention, control vent 40 in the second conduit must be at a vertically higherlevel than port means 28 in the first conduit in order to maintain first conduit port means 28' immersed in heated liquid. With this arrangement, pumping means 26 can operate continuously to draw heated water through first conduit port means 28 in order to preheat incoming liquid through first conduit 20 prior to its discharge through first conduit outlet 24 in the lower portion of the tank.

In the preferred arrangement shown in FIG. 1, first conduit port means 28 is located vertically higher in the upper portion of the tank than is heated liquid inlet port 44. Thus the hottest water in the tank which collects in the area of liquid surface 46 is not discharged into the final mixing chamber 32 through inletport 44. It is drawn off through first conduit port means 28 to be used to preheat incoming liquid in first conduit 20. This arrangement not only increases the temperature of such incoming liquid but also assists in the heating of the lower temperature liquid after it is discharged through first conduit outlet 24 and it rises through relatively cooler liquid in the tank.

The action of circulating the hottest tank liquid with the incoming liquid reduces the heating cycle time requiredby the heating means 50. Also, such action maintains overall tank temperature uniformity for quicker recovery after liquid is drawn from the tank. In addition, as was mentioned before, any pressurized air introduced with the incoming liquid cannot pass directly into mixing chamber 32. Hence such air cannot pass directly through a shutoff faucet or valve generally associated with liquid discharge means 36.

As was mentioned before, the function of pumping means 26 in first liquid carrying conduit 20 is to draw heated liquid through first conduit port means 28. It will be understood that this function can be accomplished through a variety of arrangements which create at least a partial vacuum or area of lower pressure within conduit 20 in the vicinity of port means 28. Thus liquid will flow preferentially from the tank through port means 28 into the interior of conduit 20 to mix with and increase the temperature of incoming liquid carried by conduit 20 for introduction into interior of tank 10.

Several useful examples of pump means 28 are shown in FIGS. 3, 4 and 5. FIG. 3 represents a simple aspirator type arrangement to draw liquid into conduit 20 through port 28. The use of a smaller diameter conduit 27, as in FIG. 4, connected, such as by brazing within conduit 20 and including port means 28 creates a somewhat greater pressure drop arrangement. The venturi of FIG. 5, created by swagging conduit 20 to reduce its diameter, includes port 28.

Although FIG. I shows the preferred relative positions of second liquid carrying conduit discharge 38 into final mixing chamber 32 and its heated liquid inlet port 44, it should be understood that a variety of arrangements and positions can be maintained in order to adjust liquid discharge. It is necessary, according to the present invention, that liquid minimum level control vent 40 be maintained in a position vertically higher than first conduit port means 28 and any other port commu nicating with final mixing chamber 32, such as heated liquid inlet port 44. However, as was mentioned before, significant advantages in efficiency and recovery time after liquid is drawn from the tank is achieved with relative positions as shown in FIG. 1. In that arrangement, control vent 40 is at the highest vertical level and first conduit port means 28 is vertically higher than heated liquid inlet port 44.

In the use of apparatus according to the present invention and constructed substantially as shown in FIGS. 1 and 2, inlet water at about 25 p.s.i.g. and at a temperature of about 60 F was fed into a tank having a liquid capacity of about 5 pints. The desired outlet temperature was at a level no greater than 140 F and preferably at about 125 F.

Tests on this apparatus within the scope of the present invention resulted in more efficient performance, lower overall tank temperature, reduction by about 50 percent of the reheat recovery time and a shorter heating cycle. In addition, previously existing problems relating to surging air pressure passing directly through the tank resulting in a condition of spraying air and water through the liquid discharge means was eliminated.

Iclaim:

1. An improved tank for heating and dispensing heated liquid, the tank being sealed except for the provision for liquid inlet and discharge and including:

an upper portion including an upper-wall;

a lower portion including a lower wall;

the tank during operation including an entrapped air cushion between the upper wall of the upper portion and the heated liquid to partially control movement of the liquid during operation and to allow for expansion of the liquid by further compression of the air cushion if the liquid becomes frozen;

heating means in the lower portion of the tank;

temperature sensing means in the tank electrically connected with the heating means to control the heating means as a function of liquid temperature in the tank; means to introduce liquid into the tank; and

liquid discharge means to discharge heated liquid from the tank; the improvement comprising, in combination:

a first liquid carrying conduit connected through a wall of the tank to introduce liquid into the tank;

a. the first conduit enclosed within the tank and extending into the upper portion and then into the lower portion and terminating in a first conduit outlet within the tank generally directed toward and in spaced relationship with the lower wall of the lower portion;

b. the first conduit having pumping means including a first conduit port means positioned in that portion of the first conduit located in the upper portion of the tank to draw heated water from the upper portion of the tank into the first conduit;

a second liquid carrying conduit enclosed within the tank;

a. the second conduit including a second conduit inlet in the lower portion of the tank in spaced relationship with the lower wall of the lower portion;

b. the second conduit extending within the tank from its inlet in the lower portion into the upper portion of the tank and discharging into a final mixing chamber;

0. the second conduit extending vertically higher into the upper portion than the first conduit port means and including a liquid minimum level control vent through a wall of the second conduit and located vertically higher than the first conduit port means to maintain the level of the liquid in the tank above the level of the first conduit port means; and

a final mixing chamber located within the tank in the upper portion;

a. the mixing chamber connected with the second liquid carrying conduit to receive liquid from the conduit and connected with the liquid discharge means; and

b. the mixing chamber including a heated liquid inlet port communicating with the upper portion of the tank to allow passage of the heated liquid from the tank into the mixing chamber to mix with cooler liquid from the second conduit prior to passage of liquid through the liquid discharge means.

2. The improved tank of claim 1 in which:

the first liquid carrying conduit is connected through a wall in the lower portion of the tank and extends in a loop from the lower portion into the upper portion and then into the lower portion;

the second conduit inlet in the lower portion of the tank is adjacent the first conduit outlet generally facing and in spaced relationship with the lower wall of the lower portion; and

4. The tank of claim 2 in which the first liquid carrying conduit is connected through the lower wall and is connected with a first conduit auxiliary inlet and drain port directed to provide a portion of inlet liquid generally along the lower wall.

Claims

1. An improved tank for heating and dispensing heated liquid, the tank being sealed except for the provision for liquid inlet and discharge and including: an upper portion including an upper wall; a lower portion including a lower wall; the tank during operation including an entrapped air cushion between the upper wall of the upper portion and the heated liquid to partially control movement of the liquid during operation and to allow for expansion of the liquid by further compression of the air cushion if the liquid becomes frozen; heating means in the lower portion of the tank; temperature sensing means in the tank electrically connected with the heating meAns to control the heating means as a function of liquid temperature in the tank; means to introduce liquid into the tank; and liquid discharge means to discharge heated liquid from the tank; the improvement comprising, in combination: a first liquid carrying conduit connected through a wall of the tank to introduce liquid into the tank; a. the first conduit enclosed within the tank and extending into the upper portion and then into the lower portion and terminating in a first conduit outlet within the tank generally directed toward and in spaced relationship with the lower wall of the lower portion; b. the first conduit having pumping means including a first conduit port means positioned in that portion of the first conduit located in the upper portion of the tank to draw heated water from the upper portion of the tank into the first conduit; a second liquid carrying conduit enclosed within the tank; a. the second conduit including a second conduit inlet in the lower portion of the tank in spaced relationship with the lower wall of the lower portion; b. the second conduit extending within the tank from its inlet in the lower portion into the upper portion of the tank and discharging into a final mixing chamber; c. the second conduit extending vertically higher into the upper portion than the first conduit port means and including a liquid minimum level control vent through a wall of the second conduit and located vertically higher than the first conduit port means to maintain the level of the liquid in the tank above the level of the first conduit port means; and a final mixing chamber located within the tank in the upper portion; a. the mixing chamber connected with the second liquid carrying conduit to receive liquid from the conduit and connected with the liquid discharge means; and b. the mixing chamber including a heated liquid inlet port communicating with the upper portion of the tank to allow passage of the heated liquid from the tank into the mixing chamber to mix with cooler liquid from the second conduit prior to passage of liquid through the liquid discharge means.

2. The improved tank of claim 1 in which: the first liquid carrying conduit is connected through a wall in the lower portion of the tank and extends in a loop from the lower portion into the upper portion and then into the lower portion; the second conduit inlet in the lower portion of the tank is adjacent the first conduit outlet generally facing and in spaced relationship with the lower wall of the lower portion; and the heated liquid inlet port of the mixing chamber is located vertically lower than the first conduit port means.

3. The tank of claim 2 in which the second conduit includes a second conduit port means vertically lower than the heated liquid inlet port of the final mixing chamber to draw heated liquid from the tank into the second conduit.