US3478184A - Valve-switch assembly for use in intravenous feeding - Google Patents

Description

R. D. col-'om 3,478,184

VALVE-SWITCH ASSEMBLY FOR USE IN INTRAVENOUS FEEDING Nov. 11, 1969 Filed Oct. 12, 1967 United States Patent O 3,478,184 VALVE-SWITCH ASSEMBLY FOR USE IN INTRAVENOUS FEEDING Robert D. Cofoid, Tonca, Ill., assignor to General Time Corporation, Stamford, Conn., a corporation of Delaware Filed Oct. 12, 1967, Ser. No. 674,923 Int. Cl. H01h 35/18, 9/00 U.S. Cl. 200-84 6 Claims ABSTRACT OF THE DISCLOSURE A magnetic float valve and switch assembly for use in the intravenous administration of liquids. A housing defines a valve chamber having an inlet at the top, `an exit at the bottom, and containing a oat valve element cooperating with a valve seat at the bottom of the valve chamber. A liquid tight switch casing is disposed within the valve chamber above the oat valve element for receiving a removable switch which is actuated by a magnetic portion on the iloat valve element. The switch is closed to actuate a feed pump when the float valve element is displaced upwardly off the valve seat, and is opened to deactuate the pump when the float valve element is seated. The float valve element is designed to be displaced upwardly olf its valve seat only when liquid is present in the valve chamber and the switch is inserted in the switch casing, so that the valve cannot be opened without closing the pump switch at the same time. Conversely, the pump switch cannot be opened without clo-sing the valve at the same time.

The present invention relates generally to a combined valve-switch assembly and, more particularly, to an irnproved magnetic valve-switch assembly for use in the intravenous administration of liquids.

In the intravenous administration of liquids, a check valve is often used between the solution vessel and the feed line leading to the patient to automatically close the feed line when the supply of liquid is exhausted so as to prevent gas from being injected into the patient. The use of such a valve is especially important where a pump is used to feed the liquid to the patient at a controlled rate and pressure, since the pump is more likely to inject gas into the patient than a simple gravity feed system. In order for such a system to be completely effective, however, the valve should be closed and the pump turned off at essentially the same time, i.e., immediately upon exhaustion of the liquid supply. Similarly, after the liquid supply has been replenished, the valve should be opened and the pump turned on at essentially the same time.

It is, therefore, a primary object of the present invention to provide an improved valve-switch assembly, suitable for use'in the intravenous administration of liquids, which automatically closes the valve and opens the switch in response to exhaustion of the liquid supply. It is another object of this invention to provide such an improved valve-switch assembly which automatically opens the valve and closes the switch in response to replenishment of the liquid supply.

A further object of this invention is to provide an improved valve-switch assembly Opf the type described above which insures substantially simultaneous operation of the check valve and the pump switch. In this connection, it is another object of the invention to provide such an assembly which prevents the pump switch from being opened before the valve is closed and, conversely, prevents the valve from opening until the pump switch is closed.

Yet another object of the invention is to provide such ICC an improved valve-switch assembly which does not interfere with the liquid ow while liquid is being administered intravenously.

A still further object of the invention is to provide such an improved valve-switch assembly which is simple and economical to manufacture.

Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the accompanying drawings, in which:

FIGURE l is a sectional elevation view of a valveswitch assembly embodying the present invention, with the valve in its closed position and the switch in its open position;

FIG. 2 is an enlarged partial sectional elevation view of the valve-switch assembly shown in FIGURE l, but with the valve in its open position and the switch in its closed position; and

FIG. 3 is a section taken along line 3-3 in FIG- URE l.

While the invention will be described in connection with certain preferred embodiments, it will be understood that it is not intended to limit the invention to these particular embodiments. On the contrary, it is intended to cover all alternatives, modifications, and equivalent arrangements as may be included within the spirit and scope of the invention as dened by the appended claims.

Turning now to the drawings and referring first to FIGURE 1, an intravenous solution 10` is fed from a supply container or vessel such as a Solution bottle 11 through a check valve 12 into a feed tube 13 adapted to be attached to the patient receiving the solution. The liquid entering the feed tube 13 is fed to the patient via a pump, indicated schematically at 14, connecetd in the feed line between the check valve 12 and the patient so as to control the feed rate and pressure. In the illustrative embodiment, the check valve 12 includes a main body cylinder 15 which forms the valve chamber (often referred to as the drip chamber) and is closed at its upper end by a cap 16 forming a longitudinal passageway 17 for admitting the solution into the valve chamber. The cap 16 also includes an elongated projection 1S adapted to t through a complemental opening in the bottle stopper 19 to receive the solution 10.

In order to open and close the check valve 12 in response to the presence and absence of solution within the valve chamber, a iioating valve element 21 is disposed within the valve chamber for cooperation with a valve seat 22 formed by an annulus 23 fitted within the upper end of a second valve cap 24 on the lowei end of the cylinder 14. More particularly, when the floating valve element 21 is displaced upwardly oif the valve seat 22, the check valve is opened to permit the passage of liquid down between the mating surfaces of the floating valve element 21 and the valve seat 22 and on down through a longitudinal passageway 25 extending through the cap 24, into the feed line 13. This open position of the valve is illustrated in FIGURE 2. When the solution supply is exhausted, eg., when the supply bottle 10 is empty, the floating valve element 21 descends to its seated position on the valve seat 22, thereby automatically closing the valve to prevent the injection of gas into the patient. The closed position of the valve is illustrated in FIGURES l and 3.

After the exhausted solution supply bottle 11 has been replaced with a fresh bottle, it may be `difficult to unseat the floating valve element 21 due to the reduced pressure in the feed tube 13 beneath the valve. For example, even if the pump 14 is turned off simultaneously with the closing of the check valve, the reduced pressure on the suction side of the pump may draw the lloating valve element so tightly against the valve seat that it is often impossible to even shake it loose. Accordingly, it is preferred to provide the check valve with a manual release mechanism, such as the slidable release plunger 27 in the illustrative embodiment. The plunger 27 is mounted concentrically within the exit passageway 25 and forms a central longitudinal passageway 28 for passing liquid from the valve chamber into the feed tube 13. The lower end of the release plunger 27 extends below the lower extremity of the cap 24 into the feed tube 13, while the upper end forms a head portion 29.

In order to release the oat valve element 21 from the valve seat 22 to reopen the valve after the fresh supply vessel has been connected to the upper end thereof, the release plunger 27 is pushed upwardly, as illustrated by the Ibroken lines in FIGURE 2, to move the head portion 29 of the plunger into engagement with a disc 30* carried onv the lower end of a rod 31 -depending from the lower end of the Valve element 21. This upward movement of the plunger 2.7 is effected by squeezing the feed tube 13 to telescope the lower end of the plunger 27 upwardly into the depending portion of the 'cap 24. As the head portion 29 of the plunger engages the disc 30, it forces the float valve element 21 upwardly away from the valve seat 22, whereupon the valve element is buoyed up by the fresh supply of liquid entering the valve chamber from the new supply vessel. It can be seen that a relatively.

small longitudinal movement of the release plunger 27 is required to reopen the valve, and the release plunger is retracted automatically by gravity as soon as the squeezed portion of the feed tube 13 is released.

In the normal retracted position of the release plunger 27, which is illustrated in FIGURE l, the upper head portion 29 of the plunger is positioned below the disc 30 iso as to permit seating of the iloat valve element 21 to close the valve. -In operation, the release plunger remains in this retracted position until the exhausted solution bottle 11 has been removed and replaced with a fresh bottle, after which the release plunger is advanced to release the float valve element as described previously.

In accordance with one aspect of the present invention, the float Valve element is provided with a magnetic portion for actuating an electrical switch removably mounted in a liquid tight switch casing within the valve chamber. Thus, in the illustrative embodiment, the float valve element 21 carries a permanent magnet 40 mounted on the underside of the top wall of the valve element for actuating a switch contained in a switch casing 41. The switch casing 41 extends all the way across the valve chamber in one direction, as shown in FIGURE l, but is spaced from the inside walls of the valve chamber in the other direction, as shown in FIGURE 3, so as to permit liquid to flow freely through the valve chamber. The switch casing 41 must be liquid tight, and i-s preferably formed as an integral part of the walls of the body cylinder 15. For example, the cylinder l15 and the switch casing 41 may be formed as a single integral unit which can be economically made of molded plastic, for example.

The purpose of the switch casing 41 is to receive a removable electrical switch assembly 42 for turning the feed pump 14 on and olf in response to the movement of the floating valve element 21, thereby synchronizing the operation of the pump 14 with the opening and closing of the check valve 12. The particular switch assembly illustrated includes a pair of electrically conductive and magnetically permeable leaf members 43, 44 carrying a pair of contact elements 45, 46 on the overlapping end portions thereof. The two leaf members 43, 44 are designed to hold the contact elements 45, 46 in normal spaced apart relationship so that the switch is normally open, as illustrated in FIGURE l. In this position, of course, the pump 14 is turned off. As the floating valve element 21 is displaced upwardly away from the valve seat 22, the magnetic attraction between the permanent magnet 40 and the permeable leaf members y4.3-, y44 draws the two leaf members downwardly toward the float valve element 21, thereby bringing the two contact elements 45, 46 into engagement with each other to close the switch, as illustrated in FIGURE 2. Accordingly, it can be seen that the switch `42 is automatically opened and closed in response to the closing and opening, respectively, of the check valve 12. More particularly, when the floating valve element 21 is in its closed or seated position illustrated in FIGURE l, the switch 42 is open so as to turn off the feed pump 14, since no solution can be supplied to the pump through the feed tube 13l as long as the valve is closed. When the valve is subsequently opened in response to a fresh solution supply, so that solution once again flows into the feed tube 13, the switch 42 is automatically closed rso as to start the pump simultaneously with the opening of the valve.

In accordance with a further important aspect of this invention, the oat valve element is adapted to be automatically displaced upwardly off its valve seat only when both (l) liquid is present in the valve chamber to exert a buoying action on the float valve element and (2) the switch is in place in the -switch casing to magnetically attract the float valve element upwardly toward the switch. Thus, the float valve element 21, including the permanent magnet portion thereof, is designed to have a specific gravity such that it will not be buoyed up off the valve seat 22 unless the switch assembly 42 is present in the casing 41 to exert a magnetically attractive force on the valve element 21. In other words, neither the buoying action of the liquid in the valve chamber, nor the magnetic attraction of the switch members, alone is sufficient to displace the floating valve element 21 from the valve seat 22, but the combination of these two forces is sufficient to effect such displacement. Accordingly, it can be seen that the check valve 12 must be opened and the pump 14 turned on at the same time, since neither event can occur in the absence of the other. Similarly, the pump cannot be turned off until the check valve has closed, since again the two events must occur simultaneously.

In order to permit the switch assembly 42 to be used with different valve units, the switch assembly 42 is adapted to be removable from the switch casing 41. This removability feature is desirable to permit disposal of the valve units, or at least cleaning thereof, while retaining the switch assembly 42 for repeated use; since the switch casing 41 is liquid tight, the switch assembly never comes into contact with the solution being fed, and thus it can be used time after time with different valve units. That is, the switch assembly does not have to be replaced or even cleaned between uses. In the particular embodiment illustrated, the switch assembly is enclosed in a separate casing 50 in order to protect the leaf members 43', 44 when the switch is removed from the casing 41 provided in the valve unit. Consequently, the switch assembly 42 itself has a virtually unlimited operating life.

As can be seen from the foregoing detailed description, this invention provides an improved check valve-switch assembly which insures substantially simultaneous operation of the check valve and the pump switch in an intravenous feeding arrangement. Since the assembly insures that the check valve is automatically closed at the same time that the pump switch is opened, it prevents the pump from being turned oif before the check valve is closed. Similarly, since the valve can be automatically opened only in the presence of the switch, thereby insuring the closing of the switch whenever the valve is opened, it prevents the valve from opening unless and until the pump is turned on. Moreover, although the valve-switch assembly is disposed inside the valve chamber in order to cooperate with the floating valve element, it does not interfere with the liquid ow while the liquid is being administered intravenously. Furthermore, the construction provided by this invention permits the switch assembly to be used time after time, while the valve structure can be made entirely of low cost molded plastic, so that it is simple and economical to manufacture.

I claim as my invention:

1. An improved magnetic float valve and switch assembly for use in the intravenous administration of liquids, said assembly comprising the combination of means defining a valve chamber, inlet means at the upper end of the chamber for admitting liquid from a supply vessel into the chamber, exit means at the lower end of the chamber for discharging the liquid into a feed line, a float valve element disposed within said valve chamber, said float valve element having a magnetic portion thereon, the lower end of said valve chamber forming a valve seat for cooperation with said iioat valve element whereby said exit means is opened when said lloat valve element is displaced upwardly oif said valve seat and is closed when said float valve element is seated on said valve seat, said means defining a valve chamber also including means deiining a liquid tight switch casing disposed within said valve chamber above said iioat valve element and adapted to permit liquid ilow between said inlet and exit means through said valve chamber, and electrical switch means removably mounted in said switch casing and including a pair of contact elements adapted for actuation by said magnetic portion of said oat valve element when said float Valve element is displaced upwardly off said valve seat, said float valve element and said switch means forming means adapted to be automatically displaced upwardly off said valve seat only when both (1) liquid is present in said valve chamber to exert a buoying action on said iioa't valve element and (2) said switch means is in place in said switch casing to magnetically attract the float valve element upwardly toward said casing.

2. An improved magnetic float valve and switch assembly as defined in claim 1 in which said electrical switch means comprises a pair of overlapping magnetically permeable leaf members carrying a pair of corresponding opposed electrical contact elements, said leaf members and said contact elements being normally spaced apart and adapted to be drawn into contact with each other in response to the magnetic attraction of said magnetic portion on said iioat valve element.

3. An improved magnetic float valve and switch assembly as defined in claim 1 in which said electrical switch means is contained in a closed casing adapted to be removably inserted in said switch casing in said valve chamber.

4. An improved magnetic oat valve and switch assembly as dened in claim 1 in which said magnetic portion of said float valve element comprises a permanent magnet mounted on said iioat valve element.

5. An improved magnetic float valve and switch assembly for use in the intravenous administration of liquids, said assembly comprising the combination of means deiining a valve chamber, a iioat valve element disposed within said valve chamber, means forming a valve seat for cooperation with said float valve element in said valve chamber, a permanent magnet mounted on said float valve element, said means deiining a valve chamber further defning a switch casing for removably mounting an electrical switch assembly in said valve chamber above said float valve element, an electric switch assembly in said casing including a pair of normally open contact members at least one of which is made of a magnetically permeable material for cooperation with said permanent magnet on said float valve element, said contact members being adapted to close in response to the displacement of said oat valve element away from said valve seat representing an open position of the oat valve, said float valve element and said switch assembly forming means adapted to be displaced away from said valve seat only when both (1) liquid is present in said valve chamber to exert a buoyingaction on said oat valve element and (2) said switch assembly is in place in said valve chamber to magnetically attractfthe permanent magnet on said iloat valve element.

6, An improved magnetic float valve and switch assembly for use in the intravenous administration of liquids, said assembly comprising the combination of means deiining a valve chamber, inlet means at the upper end of the chamber for admitting liquid from a supply vessel into the chamber, exit means at the lower end of the chamber for discharging the liquid into a feed line, a float valve element disposed within said valve chamber, said float valve element having a magnetic portion thereon, the lower end of said valve chamber forming a valve seat for cooperation with said oat valve element whereby said exit means is opened when said float valve element is displaced upwardly oif said valve seat and is closed when said float valve element is seated on said valve seat, a liquid tight switching casing disposed within said valve chamber above said oat valve element and adapted to permit liquid flow between said inlet and exit means through said valve chamber, and electrical switch means removably mounted in said switch casing and including a pair of contact elements adapted for actuation by said magnetic portion of said float valve element when said iioat valve element is displaced upwardly oli said valve seat, the specific gravity of said float valve element and the magnetic attraction between said magnetic portion of said iloat valve element and said switch means being designed to maintain Said float valve element on said valve seat in the absence of liquid in said valve chamber or in the absence of said switch means in said switch casing, and to displace said float valve element upwardly of said valve seat when liquid is present in said valve chamber and said switch means is in said switch casing at the same time.

References Cited UNITED STATES PATENTS 2,474,929 7/ 1949 Boler 200-84 2,791,657 5/1957 Bloxsom et al.

2,941,712 6/1960 Cook 200k-84 X 3,242,474 3/ 1966 Gast et al 200-84 X ROBERT K. SCHAEFER, Primary Examiner D. SMITH, I R., Assistant Examiner U.S. Cl. X.R. 335-205

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