HOT WATER DELIVERY

Abstract

A domestic pipe system for delivery of hot water includes hot water source (10) and a piping to a faucet (12). The piping comprises a splitter (14), two pipes (20, 22) and a controller (16), the controller having a housing, first and second inlets (24, 26), an outlet (28), and a thermally actuated valve. The first inlet is a permanently open inlet whereas the second inlet is opened depending on the temperature of water arriving at the controller. Stagnant water that cooled down only runs through the first pipe (20) until the temperature exceeds a preset threshold. Than the controller (16) opens the second inlet such that the stagnant cold water from the second pipe can be mixed gradually with the hot water from the first pipe. Thus, the user receives warm water earlier than if both pipes need to be emptied.

Claims

1-41. (canceled)

42. An apparatus for delivery of fluid, said apparatus comprising a mixing chamber, a first inlet, a second inlet, and an outlet, wherein said first inlet admits a first flow into said mixing chamber, wherein said second inlet admits a second flow into said mixing chamber, and wherein said outlet permits a third flow to exit said mixing chamber, wherein said first flow has a first-flow temperature, wherein said second flow has a second flow temperature, wherein said third flow has a third flow temperature, wherein said first flow and said second flow originate from a source maintained at a first temperature, wherein said second-flow temperature at said second inlet is initially at a second temperature, wherein as said second flow continues, said second-flow temperature at said second inlet approaches said first temperature, wherein said third flow has a third-flow temperature at said outlet that is initially at said second temperature, wherein as said second flow continues, said third-flow temperature at said outlet approaches said first temperature, wherein said third flow comprises said second flow, and wherein an extent to which said first flow contributes to said third flow is controllable in response to said third-flow temperature.

43. The apparatus of claim 42, further comprising a control system that controls flow through said first inlet, wherein in response to detecting that a difference between said first and second temperatures has fallen below a threshold value, said control system increases flow through said first inlet.

44. The apparatus of claim 42, further comprising a valve having a valve body, wherein said valve body is configured to transition between a first state and a second state, wherein, in said first state, said valve body allows flow through said first inlet and through said second inlet, and wherein, in said second state, said valve body blocks flow through said first inlet.

45. The apparatus of claim 44, further comprising an actuator coupled to said valve body, wherein said actuator applies a force to move said valve body, wherein said actuator causes a transition between said first and second states when said third-flow temperature has sufficiently approached said first-flow temperature.

46. The apparatus of claim 42, wherein said fluid comprises hot water, wherein said apparatus comprises a controller, wherein said controller comprises a housing, said first inlet, said second inlet, said outlet, and a thermally actuated valve, wherein said housing defines a mixing chamber for receiving water from said first and second inlets, wherein said first inlet is a permanently open inlet for enabling water to enter said mixing chamber, wherein said second inlet is an inlet for enabling water to enter said mixing chamber depending on a position of said thermally-actuated valve, wherein said controller outlet is an outlet enables water to exit said mixing chamber, and wherein said thermally-actuated valve opens said second inlet when a temperature of water in said mixing chamber exceeds a threshold.

47. The apparatus of claim 46, wherein said first inlet is configured to receive a first water-guide, wherein said second inlet is configured to receive a second water-guide, wherein said first water-guide has a first cross-sectional area, wherein said second water-guide has a second cross-sectional area, and wherein said first cross-sectional area is the same as said second cross-sectional area.

48. The apparatus of claim 46, wherein said first inlet is configured to receive a first water-guide, wherein said second inlet is configured to receive a second water-guide, wherein said first water-guide has a first cross-sectional area, wherein said second water-guide has a second cross-sectional area, and wherein said first cross-sectional area differs from said second cross-sectional area.

49. The apparatus of claim 48, wherein said second cross-sectional area is greater than said first cross-sectional area.

50. The apparatus of claim 46, said thermally-actuated valve comprises a valve body and a thermal actuator, wherein said thermal actuator is connected to said valve body, wherein said valve body is disposed to transition between a first position and a second position, wherein in said first position said valve body blocks said second inlet, wherein in said second position said valve body opens said second inlet, and wherein said thermal actuator moves said valve body from said first position to said second position in response to an increase in temperature.

51. The apparatus of claim 50, wherein said first position is axially displaced from said second position.

52. The apparatus of claim 50, wherein said first position is angularly displaced from said second position.

53. The apparatus of claim 50, wherein said valve body comprises openings facing said controller outlet to enable water in said mixing chamber to flow through said controller outlet.

54. The apparatus of claim 50, further comprising a spring connected to said valve body, wherein said spring is disposed to urge said valve body into said first position to block said second inlet.

55. The apparatus of claim 46, further comprising a set point control for controlling a set point at which said thermally actuated valve will open said second inlet.

56. The apparatus of claim 46, further comprising a flow splitter having a splitter inlet, a first splitter-outlet, and a second splitter-outlet, wherein said first splitter-outlet is connected to said first inlet of said mixing chamber and said second splitter-outlet is connected to said second inlet of said mixing chamber.

57. The apparatus of claim 56, further comprising a first water guide and a second water guide, wherein said first water guide connects said first splitter-outlet to said first inlet, and said second water guide connects said second splitter-outlet to said second inlet.

58. The apparatus of claim 57, wherein said first water guide has a first volume, wherein said second water guide has a second volume, and wherein said first volume differs from said second volume.

59. The apparatus of claim 58, wherein said second volume exceeds said first volume.

60. The apparatus of claim 57, wherein said first water guide has a first volume, said second water guide has a second volume, and said first volume equals said second volume.

61. The apparatus of claim 42, wherein said first-flow temperature is a time-varying temperature that varies according to a first temperature function, wherein said second-flow temperature is a time-varying temperature that varies according to a second temperature function, wherein said first temperature function has a first derivative that is, on average, positive, and wherein said second temperature function has a first derivative that is, on average, positive.

62. The apparatus of claim 61, wherein said first derivative of said first temperature function is greater than said first derivative of said second temperature function.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] FIG. 1 shows a system in which a controller for controlling hot water flow has been installed; and

[0029] FIG. 2 shows the components of a typical controller of the type used in FIG. 1.

DETAILED DESCRIPTION

[0030] FIG. 1 shows a hot water source 10 and a faucet 12 connected by a splitter 14 and a controller 16 in series. Although the illustrated embodiment features a faucet 12, any hot-water consuming device can be used. For example, the faucet 12 could be replaced by an appliance, such as a washing machine, or it could be replaced by some other type of plumbing fixture.

[0031] A first pipe 18 connects the hot water source 10 to the splitter 14. Second and third pipes 20, 22 connect the splitter 14 to corresponding first and second controller-inlets 24, 26 of the controller 16. In one embodiment, the second pipe 20 has a smaller diameter than the third pipe 22. A controller outlet 28 connects ultimately to the faucet 12.

[0032] The controller 16, shown in more detail in FIG. 2, features a mixing chamber 29 in which is disposed a thermally actuated valve 30 having a valve body 32. The valve body 32 has holes 34 to enable fluid to pass out the controller output 28. A spring 36 biases the valve body 32 into a first position in which the valve body 32 seals off the second inlet 26. The first inlet 24, on the other hand, is always open.

[0033] A thermal actuator 38 has a length that varies with temperature. In particular, the length increases as the temperature increases. The actuator 38 contacts the valve body 32. As a result, when the actuator 38 is exposed to heat, it increases its length and pushes the valve body 32 along a first direction, which is against the force exerted by the spring 36. When the actuator 38 is cooled, it decreases its length, in which case the spring 36 pushes the valve body 32 backward along a second direction opposite to the first direction. A setting knob 40 moves the actuator in and out and thus provides a way to adjust the set point of the controller 16.

[0034] In operation, when a user turns on the faucet 12, water from the second pipe 20 flows into the mixing chamber 29 through the first inlet 24, and out the holes 34 in the valve body 32 to the controller outlet 28. This water is initially cold. However, after a time that depends on the volume of the second pipe 20 between the controller and the mixer, the water will begin to run hot. If the second pipe is narrow, this volume is small. As a result, hot water will begin to come out the faucet 12 very quickly. Of course, since the diameter is small, the volume rate of flow will be low.

[0035] However, as the water in the chamber 29 heats up, the actuator 38 will lengthen and slowly push the valve body 32 in the first direction. This will gradually open the second inlet 26. As the second inlet 26 is gradually opened, a little bit of water from the third pipe 22 begins to enter the mixing chamber 29. This water is still cold. However, since the water in the chamber 29 is already hot, this cold water will mix with the hot water. Meanwhile, since water is now running in the third pipe 22, the water temperature in the third pipe 22 will slowly climb. Eventually, the water temperature in the third pipe 22 will be the same as that in the second pipe 20, at which point the second inlet 26 will be fully opened.

[0036] The principle of the invention is independent of the relative sizes of the second and third pipes 20, 22. Although having the second pipe 20 be narrower than the third pipe 22 is advantageous, the principle of dividing the flow into two pipes to decrease the hot water waiting time is applicable where the second and third pipes 20, 22 have the same diameter.

[0037] In effect, the temperatures of water flowing in the first and second pipes 20, 22 are defined by corresponding temperature functions. Assuming the pipes 20, 22 have reached thermal equilibrium with the environment, the temperature functions in both cases will have initial values equal to the ambient temperature. Because the pipes 20, 22 are connected to a hot water source 10, the ambient-temperature water will gradually be replaced by hot water. The temperature functions will therefore asymptotically approach the same value, which corresponds to the temperature of the hot water source 10. However, the average derivative for the temperature functions will differ. This means that one of the two pipes 20, 22 will reach the hot water temperature sooner.

[0038] The foregoing apparatus thus has, among its advantages, the ability to deliver hot water to where it is needed faster than a conventional hot-water delivery system. An additional advantage is that there is less wasted water because one does not have to waste as much of the standing cold water in a hot-water pipe.

[0039] Although the system has been described in terms of shortening the delivery time for hot water, it should be understood that it also works when the roles of hot water and cold water are reversed.