Pumps – With condition responsive pumped fluid control – Pump inlet or pump chamber vented to ambient
Reexamination Certificate
1999-07-20
2001-01-09
Walberg, Teresa (Department: 3742)
Pumps
With condition responsive pumped fluid control
Pump inlet or pump chamber vented to ambient
C417S300000, C417S541000
Reexamination Certificate
active
06171073
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a safety device for fluid transfer systems and, more particularly, to a safety device for eliminating vacuum pressure in the system upon detecting a change in the negative pressure levels in the system that deviates beyond a predetermined operational range, thereby removing a suction force at open ends of intake lines in the system.
2. Description of the Related Art
Drowning is the second leading cause of unintentional injury related deaths to children 14 years old and younger. Most drownings occur in swimming pools and hot tubs, and in many incidents (involving both adults and children) the main culprit is the water circulation system. In a typical pool, the circulation system includes a main drain suction intake line and at least one skimmer suction intake line, both of which feed into a main intake line that leads to a pump. A return line directs water flow back into the pool.
Most people do not feel threatened by a pool's circulation system, including the main drain intake on the bottom of the pool, and the skimmer boxes along the side of the pool. However, if a person comes into contact with any of the suction intake lines of the circulation system (at either the main drain or skimmer intakes) causing the suction intake to be covered or obstructed, the immense suction of the pump forms an instant seal between the open end of the suction intake line and the person's skin or clothing. This may result if a person places their hand over the open end of the suction intake line or, as often happens with children, a person sits down on the suction intake. In either case, the force needed to pull them free often exceeds 800 pounds. Moreover, the injuries which are inflicted in a matter of a few seconds are horrific, usually permanent and sometimes fatal. If a person, especially a child, is sucked onto the main drain suction intake on the bottom of the pool, they usually drown.
The only way to free a person sucked onto the intake of a circulation system of this type, without causing severe injury or dismemberment, is to interrupt or disable the source of the suction force, i.e., the pump. This can be done by interrupting power to the pump. However, even if the pump is shut down, a vacuum can remain in the intake side of the system between the pump and the obstructed end of the suction intake line. Sometimes, a victim could still be freed with some assistance, although serious injury or death may result. Ideally, if the vacuum in the intake line can be quickly eliminated after a victim becomes stuck to the intake, the victim will be freed with little or no assistance and without injury.
In most instances wherein a victim becomes stuck to an intake of a circulation system, typically in a swimming pool or hot tub, rescuers fail to realize the need to immediately shut off the pump. Instead, in a panic, people tend to go to the victim and attempt prying them free. In the rare instance this is successful, the injuries are often severe and permanent. Of course, there are also instances wherein there are no other people present to come to the victim's rescue. These situations are almost always fatal.
The imminent danger presented by fluid circulation systems of the type commonly found in swimming pools, hot tubs, and the like has been longstanding in the art. Little, if any, attention has been given to providing a satisfactory solution to this deadly problem that exists in every swimming pool, hot tub, as well as all other fluid circulation systems wherein a fluid is drawn from a reservoir through one or more suction intakes by a pump. Accordingly, there has been and there remains an urgent need to provide an effective means of preventing death and injury to those otherwise unfortunate victims who become unexpectedly attached by suction to the intake of a fluid circulation system.
SUMMARY OF THE INVENTION
The present invention is directed to a device for use in a fluid transfer and/or circulation system of the type including at least one pump which draws water from a reservoir through one or more intake lines each extending from an open end at the reservoir to an intake of the pump. The primary purpose of the invention is to save lives and property by alleviating the intense vacuum that builds when one or more of the suction intake ports of a pump assisted fluid circulation system becomes obstructed. The safety device includes means for sensing negative pressure levels in the fluid transfer/circulation system and means for analyzing the sensed negative pressure levels. Each time the pump is activated, the safety device analyzes negative pressure levels throughout a start-up period in order to establish a normal operating negative pressure range or window for that particular system. During the start-up period, if the negative pressure level fails to stabilize (e.g., vacuum pressure rises beyond a predetermined maximum high or drops below a predetermined low level) within a predetermined operational range which is programmed in the device, the device triggers vacuum pressure relief means and disables the pump. Otherwise, once the normal operating negative pressure window has been established, following a normal start-up, if the device detects a deviation of the negative pressure level outside of a normal operational range, the vacuum pressure relief means are actuated in order to eliminate negative pressure in the system, thereby removing suction at the open ends of the intake lines. The device also disables the pump, shutting it off, upon detecting the abnormal negative pressure level. In the event there is an absence of negative pressure due to lack of fluid movement (e.g., broken pipes, reservoir dry, etc.), the device triggers the vacuum pressure relief means and disables the pump, thereby preventing damage to the system. Warning devices, including audible and visible alarms, may be provided to indicate that operation of the fluid transfer system has been interrupted. This is especially useful to alert users to the possible occurrence of an obstruction of the intake lines by a person or object and the need to inspect and reset the device prior to reactivating the fluid transfer system. Other options can also be integrated with the device, including remote audible alarms, visual indicators, a remote panic switch, and the like.
OBJECTS AND ADVANTAGES OF THE INVENTION
With the foregoing in mind, it is a primary object of the present invention to provide a safety device for use in a fluid transfer/circulation system, wherein the device is structured to eliminate negative pressure in the system upon detecting a negative pressure level being outside of a selected operational range, thereby removing suction at the open ends of the intake lines.
It is a further object of the present invention to provide a safety device which is particularly useful in the fluid circulation systems of swimming pools, hot tubs and the like for preventing death and injury to persons or animals which become attached by suction to the intake openings of the system.
It is still a further object of the present invention to provide a safe, reliable and relatively inexpensive safety device for easy installation to existing fluid transfer/circulation systems and which automatically adjusts to any system, each time the fluid begins to flow, thereby establishing a normal operating range for each system, and wherein the device is structured to eliminate negative pressure in the system upon detecting a negative pressure level being outside (high or low) of a predetermined maximum range or the established normal operating range, thereby removing suction at the open ends of the intake lines.
It is still a further object of the present invention to provide a reliable, relatively inexpensive safety device for use in a fluid transfer/circulation system of the type including at least one pump which draws water from a reservoir through one or more intake lines, wherein the device is structured to deactivate the pump(s) and to furth
Fritze Mark
McKain Paul C.
Rizzi David
Downey P.A. Robert M.
Patel Vinod D
Walberg Teresa
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