Fluid handling – With heating or cooling of the system – Hot and cold water system having a connection from the hot...
Reexamination Certificate
2000-08-01
2001-05-08
Chambers, A. Michael (Department: 3753)
Fluid handling
With heating or cooling of the system
Hot and cold water system having a connection from the hot...
C236S012160, C236S012170, C417S012000
Reexamination Certificate
active
06227235
ABSTRACT:
FIELD OF THE INVENTION
The invention related to hot water distribution system, and more specifically to recirculation pumps for assuring instantaneous hot water delivery from a hot water tap.
BACKGROUND OF THE INVENTION
Hot water recirculating systems are known in which the cooled down water content of the hot water distribution line is conveyed back into the hot water tank via a recirculation pipe as disclosed in the earlier U.S. Pat. No. 5,143,049. Modifying an existing water distribution system requires the installation of additional piping, which may be difficult to install. A different hot water recovery system is disclosed in U.S. Pat. No. 5,009,572 Imhoff et al. and U.S. Pat. No. 5,143,049 Laing, in which a recirculation pump is switched on if the hot water temperature near the faucet drops below a pre-determined level or as soon as a hot water faucet is opened. U.S. Pat. No. 5,277,219, Lund discloses a recirculation system in which the pump is activated by temperature sensors positioned near each hot water faucet. The pump conveys the cooled-down content of the hot water distribution line through the cold water distribution line back into the water heater. Thus the faucets in the distribution line receive warm water from the water heater when the cooled-down water content between the water heater and the faucets has been pumped into the cold water distribution line.
The aforesaid U.S. Pat. Nos. 5,009,572 Imhoff et al.; 5,143,049 Laing et al.; and 5,277,219 Lund are incorporated into this specification by this reference.
The prior art systems that recirculate the cooled-down portion of the hot water distribution line directly through the cold water distribution line have several drawback. The most serious is the fact that the system of Lund does not provide instant hot water because the pump does not start before the hot water faucet is turned on, so that hot water is only available when the hot water from the water heater has reached the faucet and has risen to the desired temperature. Indeed, the first volume of water coming from the hot water heater is cooled down by the cold water pipe, and a considerable amount of water must be drawn through the hot water faucet before that desired temperature is reach. A further disadvantage lies in the use of solenoids because they are expensive and prone to failure by lime deposits.
The present invention avoids these drawback.
SUMMARY OF THE INVENTION
The primary object of the invention is to improve the operation of a hot and cold water distribution system by simplifying the recirculation circuit; assuring an immediate supply of hot water to a hot water faucet by draining any cooled down water in the hot water distribution line into the cold water distribution line for recirculation into the water heater. Aim of the invention is to prevent the drawing of warm water that has purged from the hot water distribution line when a cold water faucet is turned on; and to prevent that cold water will be conveyed into the hot water distribution line when a hot water faucet is turned on, whereby in both cases a pressure drop is caused in the water distribution line by the friction within the line; and to do this with a minimum number of simple, inexpensive and reliable components, and system installation time.
These and other valuable objects are achieved by means of a recirculation circuit that in its simplest form consists essentially of a pump, a valve mounted in series between the most distal point of the hot water distribution line and the cold water distribution line and a temperature sensor. The pump is activated whenever the temperature sensor positioned at the most distal of the hot water distribution line senses that the temperature of the hot water distribution line has fallen below a present level. The valve will prevent flow of cold water into the hot water distribution line when a hot water faucet is turned on, and will prevent hot water from flowing into the cold water distribution line when a cold water faucet it turned on. Each time a faucet is opened, the pressure in that line goes down, caused by the friction within the relevant line.
Brief Description of the Drawings
FIG. 1
shows a system with a circular pump and a bimetal helix.
FIG. 2
shows a circular pump with a valve activated by a jet produced by said pump.
FIG. 3
shows the arrangement of
FIG. 2
in a cross section parallel to the axis of rotation of the pump.
REFERENCES:
patent: 2247227 (1941-06-01), Findley
patent: 3090559 (1963-05-01), Bayer
patent: 3397841 (1968-08-01), Kieslich
patent: 3741195 (1973-06-01), Ellis
patent: 3987819 (1976-10-01), Scheuermann
patent: 5105846 (1992-04-01), Britt
patent: 5603344 (1997-02-01), Hall, Jr.
Laing Birger Johannes
Laing Johannes Nikolaus
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