the accompanying drawings are intended to provide further understanding of the invention and are incorporated in and constitute a part of the description of the invention . the drawings illustrate an embodiment of the invention and together with the description illustrate principles of the invention . the drawings should not be taken as implying any necessary limitation on the essential scope of invention . the drawings are given by way of non - limitative example to explain the nature of the invention . for a more complete understanding of the instant invention reference is now made to the following description taken in conjunction with accompanying drawings . the various features of novelty which characterize the invention are pointed out specifically in the claims which are a part of this description . for a better understanding of the invention , reference should be made to the drawings and descriptive matter in which there are illustrated and described preferred embodiments of invention . referring now to the drawings , wherein like numerals designate identical or corresponding parts throughout the referred views , fig1 shows various embodiments of an apparatus 22 connecting a reservoir 13 to a machine 19 . the reservoir 13 can be a glass bottle or any other container capable of containing a liquid . in this embodiment , the liquid is a volatile anesthetic . at its top , the reservoir 13 includes an opening 16 ( see fig5 b ) through which liquid anesthetic may be transferred from the reservoir 13 to the apparatus 22 , and ultimately to the machine 19 . in this embodiment , the machine 19 is a vaporizer that dispenses anesthetic to a person undergoing a medical procedure and the apparatus 22 is a closing mechanism connecting the vaporizer 19 the reservoir 13 . the reservoir 13 can connect to the closing mechanism 22 by any commonly known method . in this embodiment , the closing mechanism 22 is attached to the reservoir 13 by a gasket 1 ( see fig5 b ) and a crimp band 2 . the connection between the closing mechanism 22 and the vaporizer 19 will be discussed in detail later in this description . fig2 provides an isometric view of a closing mechanism 22 according to various embodiments for selectively allowing liquid to transfer from a reservoir 13 to a vaporizer 19 . the closing mechanism 22 includes a frame member 28 and a nozzle 25 . the nozzle 25 is connected to the frame member 28 , and the nozzle is moveable between a first position and a second position relative to the frame member 28 . the first position of the nozzle can prevent the passage of liquid within the closing mechanism 22 ( as shown in fig5 b ), and the second position of the closing mechanism 22 can allow such passage ( as shown in fig6 b ). the frame member 28 comprises a base 10 configured for connection to the reservoir 13 . as discussed with regard to fig1 , the base 10 can be configured for connection to the reservoir by a gasket 1 and crimp band 2 , or by any other commonly known method . the opposite end of the frame member 28 can be surrounded by the nozzle 25 . the nozzle 25 is configured for connection to a machine , such as the vaporizer 19 . for example , the nozzle 25 can define an external threading 5 for engaging an internal threading of a receiving station 37 of a vaporizer 19 . further , a sealing member 6 , such as an 0 - ring , can be in contact with the nozzle 25 and can allow for a seal between the nozzle 25 and the receiving station 37 of the vaporizer 19 . fig3 shows a side view of the closing mechanism 22 . from this view , it is shown that a biasing member 40 can be connected at one end to the base 10 of the frame member 28 and at the opposite end to the nozzle 25 . the biasing member 40 can be a spring , such as a torsion spring . as will be discussed in greater detail below , the biasing member 40 can apply a biasing force between the frame member 28 and the nozzle 25 to prevent the flow of a liquid . fig4 shows the frame member 28 apart from the nozzle 25 . from this view , one can observe the base 10 of the frame member 28 and the defining of a threading 4 configured for engagement with the nozzle 25 . fig4 further shows a first end 14 of the frame member 28 , a second end 15 of the frame member 28 , and a frame passage 11 that extends from the first end 14 of the frame member 28 to the second end 15 of the frame member 28 . through the frame passage 11 , liquid can flow between the first end 14 and second end 15 of the frame member 28 . fig5 a shows the closing mechanism 22 connected to a reservoir 13 and a vaporizer 19 . fig5 b shows the cross section at fig5 a &# 39 ; s cross axis where the nozzle 25 is at the first position such that plug member 28 prevents the passage of liquid within the closing mechanism 22 . as previously discussed , the reservoir 13 can connect to the base 10 of the frame member 28 by a standard crimp band 2 and gasket 1 arrangement . fig5 b further shows that the frame member 28 can be threadedly connected to the nozzle 25 , where the nozzle 25 and the frame member 28 can respectively define a threading 4 configured for mutual engagement . a sealing member 3 in contact with the frame member 28 and nozzle 25 , such an 0 - ring , can be included to provide a sliding seal between the frame member 28 and the nozzle 25 . the nozzle 25 further defines a plug member 8 configured to block the second end 15 of the frame passage 11 when the nozzle is in the first position , thus preventing the passage of liquid through the frame passage 11 , and thus preventing the passage of liquid from the reservoir 13 to the vaporizer 19 . the biasing member 40 applies a biasing force between the frame and the nozzle so that the plug member is normally in this first position . the discussion of fig6 b below further describes the relationship between the plug member 8 and the biasing member 40 . the external threading 5 of the nozzle 25 allows the closing mechanism 22 to connect with the receiving station 37 of the vaporizer 19 . to connect the closing mechanism 22 to the vaporizer 19 , a user can apply an initial rotation force to the reservoir 13 ( already connected to the closing mechanism 22 ) such that the nozzle 25 engages the receiving station 37 by the external threading 5 . as discussed above , the sealing member 6 allows a seal between the nozzle 25 and the receiving station 37 . when the nozzle 25 is fully engaged with the receiving station 37 and can no longer rotate , the plug member 8 of the nozzle 25 has advanced sufficiently that it can press against an activation rod 7 of the receiving station 37 , thereby opening the valve of the vaporizer 19 . fig6 a and 6b show how the reservoir 13 can be opened to the vaporizer 19 . fig6 a shows the closing mechanism 22 connected to the reservoir 13 . to better illustrate the closing mechanism , the vaporizer 19 is not shown in this figure ; however , the vaporizer 13 would be fully engaged with the closing mechanism 22 ( as in fig5 a and 5b ) before the reservoir 13 was opened to the vaporizer 19 . fig6 b shows the cross section at fig6 a &# 39 ; s cross axis where the nozzle 25 is at the second position such that plug member 28 does not prevent the passage of liquid within the closing mechanism 22 . once the nozzle can no longer rotate with respect to the vaporizer &# 39 ; s receiving station 37 , a user can apply a continued rotation force to the reservoir 13 suitable to overcome the biasing force of the biasing member 40 . when this biasing force is overcome , the frame member 28 begins to rotate with respect to the nozzle 25 by the threading 4 . as the reservoir 13 is rotated , the frame member 28 and the nozzle 25 rotate relative to each other such that the nozzle 25 moves to the second position where the plug member 8 no longer blocks the second end 15 of the frame passage 11 . at this stage , the frame passage 11 is opened , thus allowing liquid to flow from the reservoir 13 through the closing mechanism 22 to the vaporizer 19 . finally , fig7 shows a view of the closing mechanism 22 looking into the nozzle 25 . at its center , this view shows the plug member 8 for engaging the activation rod 7 . this view also shows a nozzle passage 17 through which liquid from the open frame passage 11 can flow out the nozzle 25 to the vaporizer 19 . fig7 also shows the external threading 5 that can engage an internal threading of a receiving station 37 of a vaporizer 19 . it is to be understood that the descriptions of the present invention have been simplified to illustrate characteristics that are relevant for a clear understanding of the present invention . those of ordinary skill in the art may recognize that other elements or steps are desirable or required in implementing the present invention . however , because such elements or steps are well known in the art , and because they do not facilitate a better understanding of the present invention , a discussion of such elements or steps is not provided herein . the disclosure herein is directed to all such variations and modifications to such elements and methods known to those skilled in the art . it is to be understood that the invention may assume various alternative orientations and step sequences , except where expressly specified to the contrary . it is also to be understood that the specific devices and processes illustrated in the attached drawings , and described in this specification are simply exemplary embodiments of the inventive concepts defined in the appended claims . hence , specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting , unless the claims expressly state otherwise . further , since numerous modifications and changes will readily occur to those skilled in the art , it is not desired to limit the invention to the exact construction and operation shown and described , and accordingly all suitable modifications and equivalents may be regarded as falling within the scope of the invention as defined by the claims that follow .