BACKGROUND OF THE INVENTION
The present invention relates to facilities which use washing machines. Specifically, an apparatus is disclosed which will prevent damage from a washing machine hose failure when left unattended.
Modern washing machines which are found in both the home and in commercial establishments are connected to hot and cold water supply pipes which supply water to the washing machine tub during washing and rinsing operations. The washing machines have first and second inlets for the hot and cold water, respectively, connected through a pair of flexible hoses to shut-off valves of a cold water and hot water supply system. During operation, the valves are open and the washing machine will fill the wash tub with water which is either cold or hot depending upon the selection made by the user. In most situations, the shut-off valves remain open except during emergencies when they can be closed if leaks occur in the washing machine or flexible hoses.
The flexible hoses are normally under static pressure when the washing machine is not operating. The water pressure in the flexible hoses may, over time, cause the hoses to burst flooding the laundry facility. If personnel are not available to intercede, the water damage can be very extensive.
Various systems have been proposed to deal with the problem of hose failure. One such system is disclosed in U.S. Pat. No. 6,427,276. In the foregoing system, a pair of electrically controlled valves are connected to the water supply pipes for interrupting the flow of water when the washing machine is not in use. A wireless interface is employed between the solenoid valves and the washing machine, so that the valves can be appropriately operated.
- BRIEF SUMMARY OF THE INVENTION
The present invention improves upon the foregoing systems of the prior art to further limit the pressure applied to the flexible hoses.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention provides a safety device to prevent flooding from occurring due to failure of a washing machine hose. A first solenoid valve is connected to a water supply pipe, and the water inlet of a washing machine is connected to the solenoid valve through a hose. The washing machine cycle controller energizes the solenoid valve connected to the water supply pipe as well as a solenoid valve internal to the washing machine which allows water to enter the washing machine wash tub. The enable signals which control each of the solenoid valves is timed so that the first solenoid valve connected to the water supply pipe is enabled after the internal solenoid valve of the washing machine is enabled. Once the tub has filled, the solenoid valve connected to the water supply pipe is closed prior to closing the internal solenoid valve of a washing machine. In this way, static pressure on a hose which is subject to potential failure is always maintained at a minimum, prolonging the life of the hose and avoiding catastrophic flooding of the facility.
FIG. 1 shows a washing machine implemented with a preferred embodiment of the invention;
FIG. 2 shows the relative timing of the enable signals to each of the solenoid valves of FIG. 1; and
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 3 is a more detailed description of the circuits for generating the enable signals of FIG. 2.
FIG. 1 shows a typical washing machine connection to hot and cold water supply pipes 24 and 25. Each of the water supply pipes 24 and 25 are equipped with manually operated shut-off valves 26 and 27. The water connections from each of the shut-off valves 26 and 27 to inlets 13 and 14 of the washing machine include a pair of solenoid valves 28 and 29 directly connected to the shut-off valves 26 and 27 as well as hoses 31 and 32. Solenoid valves 28 and 29 are in the normally off position, and operated under control of signals supplied through cable 30. When washing machine 10 enters a wash or rinse cycle, signals through cable 30 will enable one or the other valves depending on the water temperature selection control 12. A lid 15 gives access to the tub 20 for loading and unloading the washing machine.
Inlets 13 and 14 are correspondingly connected to solenoid valves 16 and 17. Each of these solenoid valves which are internal to the washing machine 10 operate under control of the cycle timer 11 as well as from the setting provided by temperature controller 12. Water from each of the valves 16 and 17 flows into the wash tub 20 of the washing machine.
The timer 11 establishes the various time intervals that comprise a wash cycle including a wash and rinse portion which fill the tub 20 with water of the selected temperature. A controller 22 connected to the timer 11 generates the appropriate signals operating the various components of the washing machine. A separate circuit 21 generates a timing signal for actuating the external valves 28 and 29 as well as valves 16 and 17 internal to the washing machine. Internal valve driver 18 supplies an on/off signal to internal valve 16 and 17, based on selected water temperature signal from controller 22 as well as an enable signal from the circuit 21. A second valve drive circuit 19 is connected through connector 32 and cable 30 to each of the solenoid valves 28 and 29. The valve driver circuit 19 also receives as an input a water temperature control signal from controller 22 and timing signal from circuit 21.
The system of FIG. 1 is arranged so that there is minimum static pressure maintained on hoses 31 and 32. When the washing machine is not in use, and the timer 11 is set to its off position, the solenoid valves 28 and 29 are disabled, and remain closed. When the machine is in use, and timer 11 enters a fill/wash portion of the cycle, internal solenoid valves 16 and 17 are energized, permitting water to flow through the valves. After a time Δt following the opening of solenoid valves 16 and 17, external solenoid valves 28 or 29, depending on the water temperature selection, are opened and water flows through hose 31 or 32 filling tub 20.
At the conclusion of filling tub 20, circuit 21 disables solenoid valves 28 or 29, shutting off the flow to hoses 31 and 32. Subsequently, at a time Δt later, circuit 21 disables the internal solenoid valve 16 or 17. The net effect of operating the solenoids in this sequence is to limit the water pressure build up within each of hoses 31 and 32 which may lead to a failure.
FIG. 2 demonstrates the relative timing for enabling and disabling the internal solenoid valves 16 and 17 and the external solenoid valves 28 and 29. When the wash cycle begins at T0, one of the internal valves is opened to allow water to enter the wash tub 20. At a later time T1, which may be Δt=0.5 seconds later one of the corresponding external valves 28 or 29 are enabled. Pressure within hoses 31 and 32 remains at a very low static value. When the wash tub 20 has filled at time t2, circuit 21 will send a signal to the external valve 28, 29 which is opened, dropping the pressure and flow within the corresponding hose 31 or 32 to essentially 0. The respective internal valve 16 or 17 is then closed at a later time t3.
A similar operation occurs during the rinse cycle. At the beginning of the rinse cycle, at time t4, one of internal valves 16 or 17 is opened. A short time later Δt, which may be 0.5 seconds, the respective external valve 28 or 29 is opened at t5 permitting the flow of water through hoses 31 and 32 into the wash tub 20. When the water level has reached the appropriate level, the external valve 28 or 29 is disabled at time t6. After a small Δt time interval, which may also be 0.5 seconds, the internal solenoid valve 16 or 17 is disabled. It is clear from the operation of FIG. 2, that the pressure within hoses 31 and 32 remains at a near zero level.
A more detailed explanation of the operation of the valve driver circuits 18, 19, circuit 21 and washing machine controller 22 is shown in FIG. 3.
Turning now to FIG. 3, the controller at 22 generates a fill signal during a wash cycle and rinse cycle to fill the tub 20. A delay circuit 40, constituting the amount of time difference between the opening of the internal and external valves, provides a delayed fill signal to the flip-flop 41. The undelayed fill signal is applied to flip-flop 42, and opens one of the internal valves by enabling the internal driver circuit 18. The delayed signal from the flip-flop 41 enables the external valve driver control circuit 19 so that, depending on the value of the H/W water temperature select signal from the controller, signal lines 30 convey an actuating signal to the appropriate external valve 28, 29.
The shut-off sequence of FIG. 2 for each of the sets of valves 16, 17, 28, 29 is initiated by a water level full signal generated by controller 22. A water level detector 23 generates a water level signal which is detected by controller 22. When the tub has filled to its capacity, a Level Full signal is produced and delayed in delay circuit 43. The undelayed signal resets flip-flop 41 sending a disable signal to external valve driver circuit 19 and the external valve 28, 29 which was opened is then closed. After a time Δt, the respective internal valve 16, 17 is closed when a delayed reset signal is applied to flip-flop 42.
Thus there has been described with respect to one embodiment a system for reducing the static pressure on washing machine hoses.
The foregoing description of the invention illustrates and describes the present invention. Additionally, the disclosure shows and describes only the preferred embodiments of the invention in the context of a apparatus for avoiding damage due to washing machine hose failure, but, as mentioned above, it is to be understood that the invention is capable of use in various other combinations, modifications, and environments and is capable of changes or modifications within the scope of the inventive concept as expressed herein, commensurate with the above teachings and/or the skill or knowledge of the relevant art. The embodiments described hereinabove are further intended to explain best modes known of practicing the invention and to enable others skilled in the art to utilize the invention in such, or other, embodiments and with the various modifications required by the particular applications or uses of the invention. Accordingly, the description is not intended to limit the invention to the form or application disclosed herein. Also, it is intended that the appended claims be construed to include alternative embodiments.