Device for Preventing Undesired Release of Liquid
Technical Field
The present invention relates to a device for preventing undesired release of liquid through a substantially flexible discharge pipe of a system or an installation supplied by or containing, at least intermittently, pressurized liquid. More particularly, the device of the invention is intended to be used as a protective device for preventing possible losses and damages caused by liquid released erroneously, from systems or installations in which the discharge pipe consists of, or comprises at least one flexible hose section.
Background Art
A number of known systems and installations working with pressurized liquid and releasing, at least intermittently, processed or used liquid through a flexible discharge pipe such as a hose, show the common characteristic feature that the free end of the flexible discharge pipe is not or not properly fixed. During operation, especially when the liquid is being discharged by a pump that forms an integral part of the system or installation, due to vibrations or other causes the flexible discharge pipe often falls down to the ground, or it becomes otherwise misplaced. This may result in the liquid being discharged to locations other than foreseen or desired causing considerably losses and damage. As a typical example, reference is made to the operation conditions of the known household washing machines. Experience and official insurance statistics show that washing machines used in households have been responsible for the overwhelming majority of damages caused by released water. Household washing machines are frequently installed and operated in bathrooms, and at intervals subject to the actual washing programme, their used water is intended to be discharged and released into the bath tub located in the bathroom. In many applications, the household washing machines are equipped with a flexible discharge tube having an upside down U-shaped free end which has to be applied to the rim or edge of the bath tube prior to starting the machine
for proper operation. Due insufficient care and attendance, or vibrations of the washing machine especially during intermediate centrifuging as part of the washing programme chosen, the free end of the flexible discharge pipe of the machine may become misplaced while the washing programme is still continued. Substantial amounts of water released from the washing machine to wrong locations other than the bath tub will cause overflow, roof leakage and other types of severe damage. In many designs of known washing machines the automatic re-filling of the machine with fresh water required after discharge for a consecutive operational step according to the programme is performed until the water level in the machine has reached a certain pre-determined water level. Since the free discharge orifice of a flexible discharge tube that has fallen down to the ground lies at a location that is substantially below said prescribed pre-determined level of the water at which the input flow of water would be terminated automatically, a continuous release of water from the machine will prevail until the error occurred is discovered.
Applications and designs of flow-controlled check valves on the one hand, are known from a number of earlier publications. Such check valves and their operation are duly disclosed, among others, in US patent specifications Nos. 5 195 552, 5 232 014 and in the published European patent application No. EP 0 559 131 Al. Examples of flow switches on the other hand, are known e.g. from US 5 081 328, 5 089 674 and 5 450 765. No prior art has been found, however, for a device that would be capable of efficiently preventing losses and damage caused by liquid, especially water, released erroneously from systems and installations outlined further above.
Disclosure of Invention
It is therefore the general object of the present invention to provide a simple and low cost device that would be capable of preventing losses and damage of the kind as described above. Another object of the invention is to provide a device by which undesired release of liquid from systems or installations supplied by or containing, at least intermittently, pressurized liquid can be prevented. According to a further object of the invention the device should be of the kind and design that can be simply and easily associated with and applied, as a supplementary kit, to most existing systems and installations, especially washing machines that are in use in a large number of households.
The above objects can be met by the provision of a, device which comprises at least one flow-controlled valve means. In accordance with the invention this valve means is mounted into, or is connected, downstream in flow direction of the liquid, to a flexible hose section of the discharge tube, and the valve means is designed as a flow-controlled check valve allowing the free flow of liquid therethrough in a substantially vertical upward direction of the liquid flow only. In preferred embodiments of the invention the device further comprises a flow switch capable of converting fluid pressure to an electric signal. Said flow switch is mounted into the discharge tube of the system or installation at a location upstream from the flow-controlled check valve in flow direction of the liquid, and an electric signal output of the flow switch is connected to an electric programme control unit of said system or installation. When applied to and used in systems or installations having an inlet pipe that consists of or comprises at least one flexible hose section for introducing, at least intermittently, pressurized liquid to the system or installation, more sophisticated and thus, preferred embodiments of the device according to the present invention may further comprise, as an option, another flow- controlled valve capable of blocking the flow of liquid if a pre-determined threshold value of the flow velocity of the liquid is reached at or exceeded. This another valve should be arranged in the inlet pipe upstream its first at least one flexible hose section in the direction of the flow of liquid.
Brief Description of Drawings
Other features and advantages of the present invention will become more fully apparent from the following detailed description of a preferred embodiment, the appended claims and the drawing figures in which
Fig. 1 shows by way of example only, an arrangement of the main functional parts of an embodiment of the present invention in normal state of operation where the device is applied to a conventional washing machine installed and operated in a bathroom,
Fig. 2 depicts the same embodiment of the invention in another state of operation where the flexible discharge tube of the washing machine has, by accident, fallen down from the rim of the bath tub and lies on the floor of the bathroom,
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Fig. 3 is a longitudinal section view of a preferred embodiment of the flow- controlled check valve of the device according to the present invention,
Fig. 4 is a bottom view of the check valve shown in Fig. 3,
Fig. 5 is a partly longitudinal section view of an embodiment of the flow switch of the device according to the present invention, and
Figs. 6 and 7 show longitudinal section views illustrating an embodiment of another valve of the device of the present invention that is applicable, for improved safety, to systems or installations having a flexible inlet pipe.
Mode for carrying out the Invention
Referring to the drawing figures, as a typical example of a system or installation supplied by and containing, at least intermittently, pressurized liquid, Fig. 1 shows a household washing machine 1 located and installed in a bathroom. As it can be clearly seen in Fig. 1, a device of the present invention is applied to the washing machine 1 in a manner that a flexible inlet pipe 12 of the washing machine 1 is connected, via a flow- controlled valve 6 which forms an optional unit of the device of the invention only, to a wall mounted water tap 2 for supplying, during operation, pressurized mains water to the machine at times determined by the actual washing programme. The input port of the valve 6 is connected directly to the water tap 2, and the valve 6 is arranged so that during water intake, the mains water flows through said valve 6 in downward vertical direction. The flexible hose inlet pipe 12 is connected to a bottom end output port of valve 6. As it will be described in greater detail further below, the valve 6 is designed so that it is capable of blocking the flow of the mains water and thus, preventing damage caused by overflow in cases when a serious sealing failure by rupture, loosening, or separating of the flexible hose inlet pipe 12 occurs. In the actual state of operation shown in Fig. 1, used water is just released through a flexible discharge pipe 10 of the washing machine 1 to a bath tub 3. The flow of water discharged from the washing machine 1 is directed to the bath tub 3 by an upside down U-shaped end portion 11 of the discharge pipe 10 that is applied loosely to the rim of the bath tub 3 to hold the flexible discharge pipe 10 in its desired position relative to the bath tub 3. In a substantially vertically oriented section- of the discharge pipe 10 a flow controlled check valve 4 of the device of the present invention is arranged. In its vertically oriented arrangement as shown in Fig. 1 the free upward flow of discharged water through the check valve 4 is allowed for. In another
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flow section between the washing machine 1 and the check valve 4 a flow switch 5 of the device of the invention is mounted into the discharge pipe 10. An electric output (not shown in Figs. 1 and 2 of the drawing) is connected to the programme control unit of the washing machine 1 for interrupting the power supply to the machine 1 when a discharge failure is detected.
Fig. 2 of the drawing shows the same installation of the washing machine 1 in another actual state of its operation which occurs, as known by experience and supported by insurance statistics, quite frequently. Here, the end portion 11 of the discharge pipe 10 became separated from the rim of the bath tub 3, and the flexible discharge pipe 10 has fallen down to and lies on the floor of the bathroom with the flow passage through the check valve 4 being oriented other than vertically. Fig. 2 shows the check valve 4 in a substantially horizontal flow passage position. Without the check valve 4 of the device of the invention, in this position of the discharge pipe 10 the water would be released from the washing machine 1 to the floor of the bathroom, and this could easily result in flood and serious damage to the flat or the housing estate incorporating the bathroom. Since however, the check valve 4 of the device is according to the invention designed so that it automatically blocks the flow of water therethrough in any orientation of its flow passage other than vertical, in the state of operation shown in Fig. 2 the check valve 4 has shut off the discharge pipe 10 whereby the erroneous release of water is prevented. In this closed state of the check valve 4 an increased water pressure is present in the blocked discharge pipe 10 whereby the flow switch 5 has been actuated, and the electric power supply to the washing machine 1 has been interrupted so that further damage that could be caused to the washing machine 1 e.g. by overloading the discharge pump thereof has also been prevented.
In Figs. 3 and 4 of the attached drawing a preferred embodiment of the flow- controlled check valve 4 of the device of the invention is illustrated, by way of example only. Fig. 3 shows in a longitudinal sectional view the check valve 4 in its normal, vertically oriented state of operation in which it allows for the free upward flow of water. The flow-controlled check valve 4 comprises, arranged within a valve body 40, a substantially resilient valve seat 43 provided by a resilient sealing member such as a rubber ring 44, and a substantially heavy closing member such as a valve ball 41. The specific density of the valve ball 41 must be substantially higher than that of the liquid flowing through the check valve 4. The valve seat 43 is arranged, in the normal operational position of the check valve 4 as shown in Fig. 3 when the liquid is flown
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through the check valve 4 in a substantially vertical upward direction, adjacent to an upper liquid output port of the check valve 4. The valve ball 41 is guided slidably between guide ribs 45 which are arranged below the valve seat 43 uniformly distributed on the inner circumference of the valve body 40 in an inner space portion 42 thereof. In the space portion 42 of the valve body 40 flow passages 48 are provided between the guide ribs 45 which flow passages 48 allow for the free flow of liquid along and around the valve ball 41 when in the normal operational position of the valve 4, the valve ball 41 is staying in a position clearly distanced from the valve seat 43, as shown in Fig. 3 of the drawing. The lowermost possible position of the valve ball 41 within the valve body 40 is determined by inwardly protruding stop surfaces of the guide ribs 45. The arrangement of the guide ribs 45 and the flow passages 48 is more clearly shown in Fig. 4 of the drawing. Hose nipples 47 and 47 are mounted to the substantially cylindrical valve body 40 at its respective ends so that the check valve 4 can be easily mounted in the flexible discharge pipe 10 of the washing machine 1 in a manner known per se. The size and the material of the valve ball 41 are dimensioned and selected so that in the normal operational position of the check valve 4 as shown in Fig. 3, the dynamic impact pressure of the flow of the discharging water is not sufficient for lifting the valve ball 41 so that it would be substantially displaced towards the valve seat 43. Hence, in this substantially vertical orientation of the flow passage within the check ball 4 the free upward flow of the discharging water through the check valve 4 is allowed for. In either orientation other than vertical however, especially in an orientation close to horizontal as shown in Fig. 2, the check valve 4 will automatically block the flow of liquid since the force generated by the impact pressure of the flow of water will act against, and it will overcome the substantially reduced flow direction component of the force of gravity, i.e. the weight of the valve ball 43. As a result, the valve ball 43 is easily displaceable by the water flowing through the check valve 4, and the impact pressure of the flow of water will move the valve ball 43 to the valve seat 43. Thus, the check valve 4 will block the flow of water, and erroneous release of water through the discharge pipe 10 is prevented. Replacing the check valve 4 in its normal operational position as shown in Fig. 3 in which the flow passage therein is oriented substantially vertically will result in the check wall 4 allowing the free flow of water therethrough again. Instead of a valve ball 41, i.e. a closing member of spherical shape, closing members of different, e.g. piston-like design can equally be used. Instead of having flow passages 48 provided between the guide ribs 45 the valve body may also be designed and shaped as a double-wall valve
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casing in which, in the open thoroughfare state of the check valve, the liquid is allowed to flow along a flow passage in the space portion between concentric walls of the valve casing.
Fig. 5 illustrates, by way of example only, a preferred embodiment of the flow switch 5 of the device according to the invention. As already mentioned further above, the flow switch 5 is to be mounted into the discharge pipe 10 of the system or installation, especially a washing machine 1 at a location upstream in flow direction of the liquid from the flow-controlled check valve 4. In the preferred embodiment of Fig. 5 the flow switch 5 comprises an expansion tube 50 of substantially resilient material. The ends of the expansion tube 50 are sealingly clamped between hose nipples 55, 56 and a casing 58 of the switch 5. When the flow switch 5 is installed in the discharge pipe 10 of the washing machine 1 in a manner as shown in Figs. 1 and 2, the expansion tube 50 forms part of the flow passage of the water to be discharged, and its inner surface is exposed to direct contact with the flow of water. A switch plunger 54 capable of actuating an electric contact 53 in the electric circuit of a solenoid 52 of a multiple contact relay 51 is directed radially against a wall portion of the expansion tube 50. The switch plunger 54 has a push button-like head portion that is arranged in an adjustable distance from the wall portion of the expansion tube 50. The radial distance between the button-like free end of the switch plunger 54 and the wall portion of the expansion tube is responsible for the working point of the electric contact, i.e. for the threshold value of the pressure at which an electric output signal of the flow switch 5 is generated. The radial distance and thus, the working point of the flow switch 5 can be adjusted to any desired pressure value by means of an adjusting screw 57. Increase of liquid pressure in the discharge pipe 10 results in an elastic radial deformation of the wall portion facing the switch plunger 54, and from a certain, pre-determined degree of such a deformation on the switch plunger 54 will be displaced radially whereby the electric contact 53 is closed, and the electric relay 51 is activated. The output signal of the electric relay is transmitted to the programme control unit of the washing machine 1. It will be readily understood that other types and designs of a flow switch can equally be used in different embodiments of the device of the present invention.
As already mentioned and indicated with reference to Figs. 1 and 2 of the drawing further above, preferred embodiments of the device comprise, at least as an option, a further flow-controlled valve 6 by the use of which losses of liquid and damage caused by overflow and flooding can be avoided with improved efficiency. A preferred
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embodiment of such a flow-controlled valve 6 is shown, again by way of example only, in Figs. 6 and 7 of the attached drawing. Fig. 6 illustrates the flow-controlled valve 6 in its normal, open state of operation while in Fig. 7 valve 6 is shown in its closed state. In a valve body 60 having pipe connectors 66, 67 at its respective input and output ports, the flow-controlled valve 6 comprises a valve seat 61 and a valve ball 63. Here, the specific density of the valve ball 63 is substantially lower than that of the liquid flowing through the valve 6. The valve seat 61 is arranged, in the normal mounting position of the valve 6 when the liquid is flown through the valve 6 in substantially vertical downward direction, adjacent to the lower liquid output port of the valve 6. The valve ball 63 is arranged slidably and in a guided manner between guide ribs 64 in a space portion 62 of the valve body 60 above the valve seat 61. The valve body 60 comprises between the guide ribs 64 flow passages 65 allowing the free flow of liquid along and around the valve ball 63 when in the normal operational position of the valve 6 the valve ball 63 is staying in a position clearly distanced from the valve seat 61 as shown in Fig 6. For initial filling up and eliminating air from the inlet pipe and the valve 6, the valve body 60 comprises a bore 69a that is by-passing, via a closure member 68a, the valve seat 61 of the valve 6, and a further bore 69b through which the inner space portion 62 of the valve 6 can be connected, via a second closure member 68b, to the surrounding atmosphere.
At a given mains pressure and at a given flow resistance of the system or installation such as the washing machine 1 upstream the flexible inlet pipe of which the valve 6 is mounted, under conditions of normal operation the flow velocity of the water is determined by said mains pressure and flow resistance, and it cannot exceed a certain upper threshold value. The size and the material of the valve ball 63 are dimensioned and selected so that in such a normal operational position of the valve 6 as shown in Fig. 6, the impact pressure of the flow of the mains water is not sufficient for pushing and pressing the valve ball 63 against the valve seat 61 so that it stays in its floating position clearly distanced from the latter. Thus, a free flow of water through the valve 6 along and around the valve ball 63 in downward vertical direction is allowed. In case of a serious sealing failure by rupture, separation or loosening of the flexible hose inlet pipe the flow resistance will diminish and the flow velocity of the water through the valve 6 will increase significantly. The buoyant force that has kept the valve ball 63 in well distanced relationship to the valve seat 61 under normal conditions of operation will be overcome by the increased dynamic impact pressure of the high speed flow of water, the
valve ball 63 will be pushed down and sealingly pressed against the valve seat 61 whereby the flow of water through the valve 6 is blocked. This closed state of the valve 6 will be maintained until repair work of the installation has been completed and the normal operational conditions has been restored. Prior to start-up or for resuming normal operation it is a necessary pre-condition to ensure that the inlet pipe and the inner space portion 62 of the valve 6 are filled up with water and free of air. This can be performed by opening, temporarily, the closure member 68a of the bore 69a so that the mains water is allowed to by-pass the valve seat 61 until the inlet pipe has been fully filled up with water. In addition to this, the system can be vented by opening the closure member 68b in the bore 69b whereby air can be released to the surrounding atmosphere, if this proves to be necessary.
Here again, instead of a valve ball 63, i.e. a closing member of spherical shape, closing members of different, e.g. piston-like design can equally be used. Instead of having flow passages 65 provided between the guide ribs 64, the valve body may also be designed and shaped e.g. as a double-wall valve casing in which, in the open thoroughfare state of the valve, the mains water is allowed to downward flow along a flow passage in the space portion between concentric walls of the valve casing.
The use of the device according to the invention in systems and installations mentioned and referred to in the present description and the appended claims provides a practically full protection against liquid losses and damage that may otherwise arise from lack of care and attendance, from occasional misplacement or incorrect installation. The device is very simple, its operation is safe and entirely automatic. Devices of the invention as well as their particular functional units can be used in a broad field of applications. In addition to washing machines as shown, by way of example only, further above, the device according to the present invention can be beneficially used e.g. in the wine industry and in other fields of technology. The output of the relay of the flow switch may, in addition to what has already been indicated further above, generate a lasting visible and/or acoustic signal indicating to the attendant or operator that a failure has occurred.
While the present invention has been described in connection with a preferred embodiment thereof associated with a washing machine in greater detail, it should be understood that there may be other embodiments which fall within the spirit and scope of the invention as defined by the following claims.
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List of Reference Signs used in the Drawing
washing machine 1 discharge pipe . 10 end portion 11 inlet pipe 12 water tap 2 bath tub 3 check valve 4 vab e body 40 valve ball 41 space portion 42 valve seat 43 rubber ring 44 guide rib 45 hose nipple 46, 47 flow passage 48 flow switch 5 expansion tube 50 relay 51 solenoid 52 electric contact 53 switch plunger 54 hose nipple 55, 56 adjusting screw 57 casing 58 valve 6 valve body 60 valve seat 61 space portion 62 valve ball 63 guide rib 64 flow passage 65 pipe connector 66, 67 closure member 68a, 68b
bore 69a, 69b