Abstract:
A pump assembly for an emergency eyewash station and method of retrofitting a plumbed emergency eyewash station is disclosed. The pump is configured into two parts, an impeller assembly and a drive assembly, that are configured to couple together. The impeller assembly is isolated from the drive assembly and can be easily replaced to ensure a sterile fluid path is maintained for the eyewash fluid. The drive assembly can be fluid powered or an electric motor as desired. The present invention allows a plumbed eyewash station to be retrofitted to use a sterile eyewash fluid. The present invention can also be used in portable eyewash station units too.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application claims priority to earlier filed U.S. Provisional Patent Application No. 60/729,526, filed Oct. 24, 2005, the contents of which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to emergency eyewash stations, and more particularly to an impeller assembly for such stations. 
     2. Background of the Related Art 
     Emergency eyewash stations take many forms, including plumbed stations, self-contained fixed-mounted units and portable units. Generally speaking, these stations are designed to dispense eyewash fluid (typically water) upon demand. 
     The plumbed eyewash stations are generally connected to the water supply pipes of an existing sink or are installed as a stand-alone emergency eyewash station with the water supply and draining connected to the regular building water systems. An example of a plumbed eyewash station is found in U.S. Pat. No. 5,740,569 issued to Gurries, II et al, which discloses a rotatable spray nozzle mounted to the base of a regular laboratory sink. The spray nozzle is piped directly into the main water supply and includes a valve that is opened when the spray nozzle is rotated into active position above the sink. Although plumbed eyewash stations generally provide instant availability of a washing spray they suffer from the disadvantage of relying on ordinary tap water as the cleansing agent. For example, tap water may carry bacteria and other unknown chemicals and contaminants that could cause infection of the eyes. It has been recognized that it would be more advantageous to have a system that used an eyewash fluid that was known to be free of foreign substances, i.e. filtered, purified or sterilized. 
     Attempts have been made to retrofit plumbed stations with an external source of eyewash fluid that has been purified or sanitized. U.S. Pat. No. 6,070,279 issued to Lundstedt discloses one such retro-fit system. However, the Lundstedt patent relies upon the force of gravity to dispense the eyewash fluid from the station. Although the force of gravity offers several other advantages, it lacks the advantage of being able to maintain a constant and steady flow of eyewash fluid from the dispensing head of the station. In fact, the pressure steadily dwindles as the reservoir empties. 
     Turning to standalone wall-mounted and portable units, these stations typically have internal reservoirs that also rely upon the force of gravity to dispense the eyewash fluid. The U.S. Pat. No. 4,881,283 issued to Liautaud shows an example of a wall-mount unit. 
     In an effort to encourage more suitable eye wash facilities, the American National Standards Institute (ANSI) promulgated voluntary standards for portable eye wash fountains relating to flushing periods and the rate of flow of wash fluid. These standards dictate that portable eye wash fountains should deliver no less than 0.4 gallons per minute (1.5 liters per minute) of eye wash fluid for a time period of at least 15 minutes. Responsive to the new ANSI standards, several new designs emerged seeking to provide the required flow rates for the minimum periods of time. For the most part, the eye wash stations currently on the market do provide the required flow rates for the minimum period of time. 
     However, newer ANSI and OSHA regulations have created additional issues that will need to be addressed, and will require improvements to the existing designs to maintain compliance. In particular, upcoming OSHA regulations will soon require the use of “sterile” eye wash fluids. As with any use of a sterile fluid, there is a desire to maintain sterility of both the source of the fluid and throughout the delivery paths and delivery mechanisms, including all delivery lines, nozzles, and pumps, if included in the delivery system. 
     Therefore, there is a need for new emergency eyewash systems to provide a sterile source of eyewash fluid, to maintain a steady and constant flow of eyewash fluid from the source, and to provide a sterile delivery path from the source to the delivery site. 
     SUMMARY OF THE INVENTION 
     The present invention seeks to solve some of the shortcomings of the prior art by providing a reusable/disposable impeller assembly that can be used by both plumbed, self-contained fixed-mount and portable emergency eyewash stations to deliver sterile fluid from the sterile source to the delivery site. 
     The impeller assembly of the present invention includes an impeller housing having an interior pumping chamber, input port into the chamber and an output port out of the chamber, and an impeller wheel rotatably mounted within the housing. The impeller wheel includes an impeller drive shaft having a drive interface that can mate with any one of multiple different drive mechanisms depending upon the installation and application. The impeller housing and wheel are designed so as to deliver the recommended 0.4 gallons per minute of fluid to the station spray nozzle. The impeller assembly is intended to be manufactured from a plastic material and is sterilized prior to installation so that the path through the impeller housing remains sterile prior to receiving the sterile eyewash fluid at the time of delivery. 
     In short, the impeller assembly is a simple sterile pump mechanism having an input port and an output port, and a drive interface for mating the impeller assembly with a drive mechanism. 
     In one embodiment, the drive mechanism comprises a second impeller wheel driven by a source of moving fluid, such as running water. This embodiment utilizes the available source of tap water as a drive mechanism to pump the sterile fluid from the source to the spray nozzles, obviating the need for any electrical power source or complicated gravity feed systems to move the sterile fluid. 
     In a second embodiment, the drive mechanism comprises an electrically powered drive motor. The impeller drive interface is mated with a corresponding interface on the drive shaft of a conventional electric motor. At the time of delivery, the electric motor is energized to drive the impeller to pump the sterile eyewash fluid from the source to the spray nozzles. This type of unit requires electrical power, and may further include a battery back-up 
     Finally, in a third embodiment, the entire eyewash station is constructed for use as a portable wheeled assembly wherein the sterile eyewash source, dispensing spray nozzles, power supply and battery backup are mounted on a wheeled cart frame so that the station can be deployed where ever necessary. 
     Accordingly, among the objects of the present invention is the provision for an impeller assembly for an emergency eyewash station that can be powered by different drive mechanism, including fluid and electric drive means. 
     Yet, another object of the present invention is the provision for an impeller assembly for an emergency eyewash station that is disposable and/or recyclable. 
     Yet, another object of the present invention is the provision of an impeller assembly for an emergency eyewash station where the impeller assembly is isolated from the means for driving the impeller assembly. 
     Yet, another object of the present invention is the provision for an impeller assembly for an emergency eyewash station that maintains a constant steady flow of eyewash fluid. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features, aspects, and advantages of the present invention will become better understood with reference to the following description, appended claims, and accompanying drawings where: 
         FIG. 1  is a cross-section view of a first embodiment of the impeller assembly of the present invention; 
         FIG. 2  is a cross-section view of the impeller assembly mated with a fluid impeller drive means; 
         FIG. 3  is a perspective view of a plumbed emergency eyewash station including a sterile eyewash fluid source, and the impeller assembly of the present invention driven by a source of plumbed tap water; 
         FIG. 4  is a is perspective view of a plumbed emergency eyewash station including a sterile eyewash fluid source, and the impeller assembly driven by a source of compressed gas; 
         FIG. 5  is a cross-section view of the impeller assembly mated with an electric motor drive; 
         FIG. 6  is a perspective view of a plumbed emergency eyewash station including a sterile eyewash fluid source, and the impeller assembly of the present invention driven by an electric motor; 
         FIG. 7  is another perspective view of a plumbed emergency eyewash station including a sterile eyewash fluid source, and the impeller assembly of the present invention driven by an electric motor, and including a battery backup; and 
         FIG. 8  is a perspective view of a portable emergency eyewash station including a sterile eyewash fluid source, and the impeller assembly of the present invention driven by an electric motor, and including a battery backup. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIG. 1 , the impeller assembly of the present invention is shown generally at  10 . The impeller assembly includes a pump housing  12  having an interior pumping chamber  14 , input port  16  into the chamber  14  and an output port  18  out of the chamber  14 , and an impeller pump wheel  20  rotatably mounted within the housing  12 . 
     The impeller pump wheel  20  includes a pump drive shaft  22  having a drive interface  24  that can mate with any one of multiple different drive mechanisms depending upon the installation and application. The impeller pump housing  12  and impeller pump wheel  20  are designed to deliver the recommended 0.4 gallons per minute of fluid to the station spray nozzle (shown in  FIG. 3 ). The impeller assembly  10  is intended to be manufactured from a plastic material and is sterilized prior to installation so that the path through the impeller pump housing  12  remains sterile prior to receiving the sterile eyewash fluid at the time of delivery. 
     Referring to  FIGS. 2 and 3 , a first embodiment of an eyewash station, shown generally at  26  in  FIG. 3 , is configured and arranged to be driven by a propellant fluid, such as running tap water or alternatively a compressed gas source (shown in  FIG. 4 ). The eyewash station has a dispensing structure  27  having spray nozzles connected to a sterile eyewash fluid source  29 . The impeller pump assembly  10  and drive impeller  28  are interposed between the sterile eyewash fluid source  29  and the dispensing structure  27 . The sterile eyewash fluid source shown includes a container, such as a sealed bottle inverted into a receiver assembly that includes a truncheon (not shown) for piercing the seal and allowing the eyewash fluid to drain into the receiver assembly and prime the station for use. Extending from the receiver assembly is a transport tube, which is connected to the impeller pump assembly  10 . The impeller pump assembly  10  is driven by a second impeller unit (impeller drive unit)  28  having a complimentary drive interface or coupler  30  at the end of an impeller drive shaft  32 . 
     The impeller drive unit  28  of the first embodiment has an impeller drive housing  34  with an intake port  36  and an exhaust port  38  defining a path for the propellant fluid. Rotatably mounted within the impeller drive housing  34  is an impeller drive wheel  40  connected to and to drive the impeller drive shaft  32 . The drive interface  30  on the impeller drive shaft  32  cooperates with the engagement interface  24  on the impeller pump assembly  10  to drive the impeller pump shaft  22  and the impeller pump wheel  20 . The impeller drive wheel  40  is positioned within the impeller pump housing  34  and is in fluid connection with the intake port  36  and the exhaust port  38  so that the propellant fluid entering the intake port  36  propels the impeller drive wheel  40  before exiting the exhaust port  38 . 
     Flow of the eyewash fluid is initiated by opening a valve  39  to start the flow of running water. As the propellant fluid forces rotation of the impeller drive wheel  40 , the impeller drive shaft  32  turns the drive interface  30  to operate the impeller pump assembly  10 . As the impeller pump wheel  20  rotates, it draws eyewash fluid through the intake port  16  into the pumping chamber  14  and projects the eyewash fluid out the exhaust port  18 . 
     Referring to  FIG. 4 , alternatively, if a source of running water is not easily accessible, the system  42  could use a container of a compressed gas  44 , such as compressed carbon dioxide gas, fed through a pressure regulator  46  as the propellant fluid. The gas flow drives the impeller drive wheel  40 , in turn pumping the eyewash fluid. 
     The impeller pump assembly  10  may be entirely removed and replaced as needed to ensure that the emergency eyewash station  26 ,  42  remains clean and free of foreign substances that may cause further injury through infection. Because the pump housing  12  remains isolated from the drive housing  34 , the drive housing  34  does not need to be replaced and may be mounted permanently with the emergency eyewash station  26 ,  42 . 
     Referring to  FIGS. 5 and 6 , the second embodiment of the impeller pump assembly of the present invention is shown generally  100 . In this embodiment, the drive means is an electric motor assembly  102 . The electric motor assembly  102  includes a motor housing  104  supporting an electric motor  106 , which drives a drive shaft  108 , which in turn drives a drive interface  110 . In all other respects, the second embodiment  100  is the same as the first embodiment  10 , with the exception of an electric switch  105  to selectively energize the motor  106  in place of a valve to start the flow of the eyewash fluid. In particular, an impeller pump assembly  112  has a pump housing  114  having a pumping chamber  116 . The pumping chamber has an input port  118  and an output port  120 . An impeller drive wheel  122  is rotatably mounted within the pumping chamber  116  and is driven by a drive shaft  124 . The drive shaft  124  is driven by an impeller drive interface  126 , which is configured to couple to and be drive by the drive interface  110  of the electric motor assembly  102 . 
     Referring to  FIG. 7 , another embodiment is illustrated and is shown to include a battery back-up power source  128  to power the electric motor assembly  102  in the event that electric power is lost during a power failure or other site emergency. 
     Referring to  FIG. 8 , a portable emergency eyewash station is illustrated in a form configured and arranged to employ the electric drive motor and battery back-up system as shown generally at  200 . In particular, the portable emergency eyewash station  200  of the present invention has body portion  202  having a pivotally attached actuator arm  204 . A reservoir  206  holding eyewash fluid is contained with the body portion  202 . A dispensing structure (not shown) is mounted on a pivoting actuator arm  204  and is connected by a dispensing hose to the second embodiment  100  of the pump of the present invention, which is connected by a feed hose to the reservoir  206 . A battery (not shown) is connected by a pair of wires (not shown) to the electric motor  106  on the pump and to a switch (not shown) by a second set of wires (not shown). The switch is positioned adjacent to the actuator arm  204  so that the actuator arm  204  depresses the switch when the actuator arm  204  is pivoted. 
     The portable emergency eyewash station  200  includes a pair of wheels  208  mounted near the bottom of the body portion  202  and a handle  210  extending rearward from the top portion of the body portion  202 . By pulling rearward on the handle  210 , an operator can wheel the portable emergency eyewash station  200  to a desired location exactly like a dolly. 
     Although the portable emergency eyewash station  200  is described embodying the electrically powered pump  100 , it could also be easily configured to receive the fluid powered pump of the first embodiment  10 . In particular, a compressed gas cylinder with an attached regulator could be configured and arranged within the body of the portable emergency eyewash station to drive the drive impeller of the pump. 
     Therefore, it can be seen that the present invention provides a unique solution to the problems of the prior art by uniquely providing a pump for an emergency eyewash station that is powered by a propellant fluid or an electric motor and has a disposable or replaceable impeller housing. 
     It would be appreciated by those skilled in the art that various changes and modifications can be made to the illustrated embodiments without departing from the spirit of the present invention. All such modifications and changes are intended to be within the scope of the present invention except as limited by the appended claims.