Abstract:
A protective device that is used in a medical suction system withdrawing liquids from a patient. The device is located upstream of a vacuum regulator and protects that regulator and other downstream components from contacting the liquid being withdrawn from the patient. The protective device has an inlet and an outlet and an actuator mechanism that can move between a contracted position where a gas can communicate through the protective device between the inlet and the outlet and an expanded position where the actuator mechanism occludes both the inlet and the outlet to shut off the vacuum supply to the patient. An electrical circuit having a pair of sensing electrodes provides an electrical discharge to trigger a shape-metal alloy wire to move the actuator mechanism from the contracted position to the expanded position when the sensing electrodes detect the presence of a liquid therebetween.

Description:
BACKGROUND  
       [0001]     The present invention relates to a medical suction system and, more particularly, to an overflow protection device that senses a liquid in a medical suction system to provide protection to components of that system.  
         [0002]     It is a common practice in the care of patients, particularly after surgery, to provide a vacuum system that carries out the withdrawal of liquids from the patient. To that end, most hospitals normally have a pipeline supply or source of vacuum that is piped to certain hospital rooms where the suction or withdrawal of liquids is being carried out. Alternatively, there may be an on-site source of vacuum actually within the hospital room itself that provides the necessary vacuum for withdrawal of the liquids.  
         [0003]     In either event, there is normally also a vacuum regulator that is present within the treatment room so that the level of vacuum can be regulated by the caregiver to a particular level of vacuum that is desired, and of course, safe, to effectively apply to the particular cavity of a patient for the withdrawal of liquid therefrom.  
         [0004]     One of the difficulties, however, in the use, for example, of a central hospital supply of the vacuum is that it is necessary to protect the vacuum regulator, as well as any further pipes, downstream equipment etc. from contamination by the biological liquids that are being removed from the patient. While the various components upstream of the vacuum regulator can be of a type that are readily cleaned or, alternatively, disposable, the downstream components and equipment including the vacuum regulator itself are of a nature that cleaning is very difficult or even not possible should the contaminated liquids actually enter the hospital piping of the central vacuum system.  
         [0005]     Accordingly, such vacuum systems normally have some device that senses or somehow is responsive to the presence of a liquid and which device then occludes the vacuum line in some manner that the liquid is prevented from traveling further downstream of that safety device.  
         [0006]     As such, therefore, one typical protective device is a collection bottle that collects the liquid from the patient and which has a ball valve and a hydrophobic filter and, while that technology generally operates well and is effective, the actual implementation of the ball valve is large and the device must be oriented in a generally vertical position to be reliable.  
         [0007]     Accordingly, it would be advantageous to have a medical suction overflow protective device that is relatively inexpensive, effective, reliable and which provides a good visible indication that it has been activated to occlude the vacuum line. It would also be advantageous for such a protective device to safely contain even that liquid removed from a patient that has entered the protective device to activate the occlusion of the vacuum line so that there is an assurance that such liquid will not leak out of the protective device and contaminate other areas of the hospital.  
       SUMMARY OF THE INVENTION  
       [0008]     Accordingly, the present invention relates to a medical suction overflow protective device that can be used in the vacuum line withdrawing liquid from a patient and provide protection for any components that are downstream of the device including the vacuum regulator. As used herein, the term upstream will refer to the direction of flow of the liquid in the vacuum system, thus, the patient is the ultimate upstream location and the source of vacuum is the ultimate downstream location.  
         [0009]     With the protective device of the present invention, there is a housing having an inlet and an outlet and which normally provides a fluid path for the vacuum that draws the liquids from the patient toward the vacuum regulator. Thus, the present protective device is located upstream of the vacuum regulator, preferable adjacent that vacuum regulator and prevents the liquid from the patient from reaching the vacuum regulator. The outlet of the present protective device is thus adapted to be connected to the vacuum regulator and the inlet connected to the patient circuit including medical tubing that eventually leads to the patient via a collection bottle and the like.  
         [0010]     An actuator mechanism is contained within the housing and that actuator mechanism has opposed blocking surfaces that are positioned, respectively, adjacent to the inlet and the outlet of the protective device. The actuator mechanism is movable between a contracted position wherein the blocking surfaces are displaced away from the inlet and outlet and an expanded position wherein the blocking surfaces block both the inlet and the outlet of the protective device.  
         [0011]     The actuator mechanism is normally biased toward its expanded position with a latch mechanism that retains the actuator mechanism in its contracted position. A pair of sensing electrodes are located along the external surface of the actuator mechanism and detect the presence of a liquid therebetween. When the liquid has been detected between the sensing electrodes, an electrical circuit, preferably battery powered, creates a brief electric discharge through a shape-metal alloy actuator that contracts to release the actuator mechanism from its contracted position so that it expands outwardly to its expanded position and which causes the blocking surfaces to occlude both the inlet and the outlet of the protective device.  
         [0012]     With both the inlet and the outlet immediately closed upon the sensing of the liquid withdrawn from a patient, not only is the vacuum regulator downstream of the protective device protected from intrusion of the biologic liquid, but the liquid that has inadvertently entered the protective device itself is also isolated since both the inlet and the outlet are rapidly closed such that any such liquid is effectively trapped within the protective device and can be disposed of in a safe manner without further leakage.  
         [0013]     As a further feature of the present protective device, there is a visual indication to the attending personnel that the protective device has been triggered to block the vacuum line and that visible indication can be a brightly colored diaphragm that is initially collapsed when the actuator mechanism is in its contracted position and has not been activated but expands to become very visible through a transparent housing as the actuator mechanism itself expands to its expanded position so as to alert the attending personnel to the fact that the protective device has been triggered and the vacuum line is closed. The overall protective device is also relatively independent with respect to orientation, that is, it functions in almost any orientation.  
         [0014]     These and other features and advantages of the present invention will become more readily apparent during the following detailed description taken in conjunction with the drawings herein. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]      FIG. 1  is a front view of a conventional vacuum regulator having a medical overflow protective device constructed in accordance with the present invention affixed thereto;  
         [0016]      FIG. 2  is a cross-sectional view of the medical overflow protective device of the present invention in its contracted position;  
         [0017]      FIG. 3  is a cross-sectional view of the medical overflow protective device of the present invention in its expanded position;  
         [0018]      FIG. 4  is a cross-sectional view of the actuator mechanism of the present invention in its contracted position;  
         [0019]      FIG. 5  is a cross-sectional view of the actuator mechanism of  FIG. 4  in its expanded position; and  
         [0020]      FIG. 6  is a schematic view of an electrical circuit that can be used with the present invention.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]     Referring now to  FIG. 1 , there is shown a front view of a vacuum regulator  10  that can be a conventional construction and which normally includes an external knob  12  that is manipulated by the user to establish the desired level of vacuum upstream of the vacuum regulator  10 . There is also normally provided, a gauge  14  that provides a visual indication to that user of the level of vacuum that has been thereby established. The vacuum regulator  10  has an inlet  16  and an outlet (not shown) that is adapted to be connected to the source of vacuum such as the hospital central pipeline of vacuum. By use of the vacuum regulator  10 , therefore, there is a vacuum level established at the inlet  16  in accordance with a setting that is established by the user via the external knob  12  and which is ultimately transmitted to a patient by a patient circuit that includes various medical tubing and generally a collection container that retains the fluids drained from the patient.  
         [0022]     As also can be seen, there is a protective device  18  that is affixed in fluid communication with the vacuum regulator  10  and the protective device  18  comprises a housing  20  that is preferably constructed of a transparent plastic material and has an outlet  22  and an inlet  24  extending therefrom. The outlet  22  of the protective device  18  is affixed to the inlet  16  of the vacuum regulator  10  and, as will be later explained, provides protection to the vacuum regulator  10  from the introduction of biological liquids received from a patient during the drainage of that patient by the medical suction system.  
         [0023]     Turning now to  FIG. 2 , there is a cross-sectional view of a protective device  18  of the present invention and illustrating the flow, by arrows A, of the gas through the protective device  18  as the vacuum draws gas therethrough. The housing  20  includes the outlet  22  and the inlet  24  and there is also an actuator mechanism  26  located internal of the housing  20  that has blocking surfaces  28 ,  30  located on opposite sides of the actuator mechanism  26  and, respectively, generally in aligned proximity to the outlet  22  and the inlet  24 .  
         [0024]     The actuator mechanism  26  can be supported within the housing  20  by a variety of means, however, as shown, there may be a plurality of light springs  32  that retain the actuator mechanism  26  in the desired position therein. In  FIG. 2 , the blocking surfaces  28 ,  30  are displaced away from the outlet  22  and the inlet  24  so that the flow of gas can pass through the protective device  18  along the path of arrows A. As will later become clear, the actuator mechanism  26  is in its contracted position in  FIG. 2 .  
         [0025]     Turning now to  FIG. 3 , the is shown a cross-sectional view of the protective device  18  with the actuator mechanism  26  in its expanded position and, as can be seen, the blocking surfaces  28 ,  30  are physically occluding the outlet  22  and the inlet  24 , respectively, such that flow through the protective device  18  is prevented by the occlusion of both the outlet  22  and the inlet  24  thereby effectively sealing the interior of the housing  20 . Again, as will become clear, the actuator mechanism  26  is in its expanded position as shown in  FIG. 3 .  
         [0026]     Turning now to  FIG. 4 , there is shown a cross-sectional view of the actuator mechanism  26  of the present invention. In this FIG., the actuator mechanism  26  is in its contracted position and comprises an upper member  34  and a lower member  36 . The upper member  34  supports the blocking surface  28  and the lower member  36  supports the blocking surface  30 .  
         [0027]     A pair of standoffs  38  are formed in the upper member  34  and may be molded therein and which support a printed circuitboard  40  that has a number of electronic components  42  affixed thereto in conventional manner. There can be, of course, other means of affixing the printed circuitboard  40  within the housing  20  and it may be affixed to the lower member  36  as well. The components that are affixed to the printed circuitboard  40  will be later described.  
         [0028]     Extending upwardly from the lower member  36 , and which can be molded or affixed thereto, are a pair of fixed latch members  44 . Each of the fixed latch members  44  includes a lip  46 . As shown, there are two fixed latch members  44  illustrated in  FIG. 4 , however, there may be a greater number used with the present invention.  
         [0029]     There are also a pair, or greater number as explained, of movable latch members  48  that depend downwardly from the upper member  34  and which also have a lip  50  formed therein. As can be seen in  FIG. 4 , the lips  46  of the fixed latch members  44  engage with the lips  50  of the movable latch members  48  to retain the upper member  34  latched to the lower member  36 , thereby retaining the actuator mechanism  26  in its contracted position. Countering the latching of the upper and lower members  34 ,  36  is a bias that tends to move the actuator mechanism  26  to its expanded position, that is, the bias is provided by a pair of springs  52  that are compressed in  FIG. 4  and which, therefore, push outwardly on the upper and lower members  34 ,  36 .  
         [0030]     A sensing electrode  54  is positioned on the external surface of the upper member  34  and a sensing electrode  56  positioned on the external surface of the lower member  36 . Each of the sensing electrodes  54 ,  56  is connected to the electronic components  42  on the printed circuitboard  40  by means of hard wires  57 . The sensing electrodes  54 ,  56  are shown on opposite surfaces of the actuator mechanism  26 , that is, on the external surfaces of the upper and lower members  34 ,  36  in order to minimize the occurrences of false activations. While the sensing electrodes  54 ,  56  can be located adjacent to each other, there is a higher likelihood of the protective device  12  activating upon the sensing of a negligible amount of a liquid and prematurely occluding the vacuum line to the patient. With the orientation as shown, therefore, the likelihood of the false activations is less likely to occur.  
         [0031]     There is also a shape-metal alloy wire  58  that is stretched between the movable latch members  48  and can be connected thereto by a variety of means, and one such means is the interfitting or connecting of enlarged ends  60  within openings  62  of the movable latch members  48 . A further set of hard wires  64  electrically connects the electronic components  42  affixed to the printed circuitboard  40  to the shape-metal alloy wire  58 . There is also located within the peripheral area of the actuator mechanism  26  and affixed to both the upper member  34  and the lower member  36 , a brightly colored diaphragm  66  that is compressed within that peripheral area. As can be seen, since the diaphragm  66  is, in  FIG. 4 , contained interiorly within the upper and lower members  34 ,  36 , it cannot be readily seen from exterior of the actuator mechanism  26 .  
         [0032]     Due to the characteristics of a shape-metal alloy wire  58 , when an electrical discharge is applied to the shape-metal alloy wire  58 , there is a heating effect and thus the shape-metal alloy wire  58  contracts and pulls the movable latch members  48  inwardly so as to disengage the lip  46  of the fixed latch member  44  from the lip  50  of the movable latch member  48  thereby releasing the interengagement of the movable latch member  48  from the fixed latch member  44  to allow the spring  52  to push the upper and lower members  34 ,  36  apart.  
         [0033]     Turning now to  FIG. 5 , taken along with  FIG. 4 , there is a cross-sectional view of the actuator mechanism  26  that has been moved to its expanded position, having been pushed to that position by means of the springs  52 . As can be seen, the diaphragm  66  has also expanded with the expansion of the actuator mechanism  26  to its expanded position so that the brightly colored diaphragm  66  is now readily visible through the transparent housing  20  ( FIGS. 2 and 3 ) to the attending personnel who can immediately visibly ascertain that the actuator mechanism  26  has moved to the expanded position and, as explained, the protective device  18  has effectively closed off the source of vacuum to a patient so that the necessary corrective action can be taken.  
         [0034]     Turning now to  FIG. 6 , taken along with  FIGS. 4-5 , there is a typical electrical circuit that can be used to activate the present invention and the components of  FIG. 6  are those that are shown as the electronic components  42  affixed to the circuitboard  40  in  FIGS. 4 and 5 . As stated, there are many electrical circuits that can be used and the present circuit of  FIG. 6  is but one usable circuit with the invention, the object being to create a brief electrical discharge to the shape-metal alloy wire  58  when a liquid is detected between the two corrosion-resistant sensing electrodes  56 .  
         [0035]     In the circuit of  FIG. 6 , there is a battery  68  that is used and which powers the electrical circuit so as to provide the electrical discharge to the shape-metal alloy wire  58 . The battery can be a lithium coin-type battery. The circuit includes a sensitive MOS field effect transistor  70 . The sensing electrodes  56  are also shown and a resistor  72  limits the flow of current through the sensing electrodes  56  in the event of a circuit malfunction. With the circuit, when a liquid is sensed between the sensing electrodes  56  i.e. there is a conduction therebetween and the circuit thereby supplies an input voltage at the gate of transistor  70  through the capacitor  74 . The capacitor  74  and resistor  76  form a circuit that limits the time that the transistor  70  is turned on. Thus, when the voltage is applied to the gate of transistor  70 , the transistor  70  conducts and passes a current through the shape-metal alloy wire  58  connected to the terminals  78 .  
         [0036]     As such, when the sensing electrodes  56  sense a liquid therebetween, the transistor  70  sends a brief electrical discharge to the shape-metal alloy wire  58  so as to contract that shape-metal alloy wire  68 , thereby disengaging the fixed latch members  44  from the movable latch members  48  to release the upper and lower members  34 ,  36  to change the actuator mechanism  26  from the  FIG. 4  contracted position to the  FIG. 5  expanded position, thereby occluding both the outlet  22  and the inlet  24  as described with respect to  FIGS. 2 and 3 .  
         [0037]     Those skilled in the art will readily recognize numerous adaptations and modifications which can be made to the protective device of the present invention which will result in an improved medical vacuum system, yet all of which will fall within the scope and spirit of the present invention as defined in the following claims. Accordingly, the invention is to be limited only by the following claims and their equivalents.