Patent Application
20080083874
Various embodiments of the present invention will be described in detail with reference to the drawings, wherein like reference numerals represent like parts and assemblies throughout the several views. Reference to various embodiments does not limit the scope of the invention, which is limited only by the scope of the claims attached hereto. Additionally, any examples set forth in this specification are not intended to be limiting and merely set forth some of the many possible embodiments for the claimed invention.
FIG. I depicts a transfer line 100 that is withdrawn from a mass spectrometer 102. The transfer line 100 includes an outer sheath 104 and an inner sheath 106, which serve to protect and thermally insulate a capillary column (not depicted) that extends through the sheaths 104 and 106. The transfer line 100 has a proximal end 108 and a distal end 110. At its proximal end 108, the transfer line 100 couples to a gas chromatograph (not depicted) via an inlet 112. At its distal end 110, the capillary column protrudes from an outlet 114 during operation of the mass spectrometer 100, as discussed further herein, below.
The mass spectrometer 100 includes a vacuum manifold 116. Housed within the vacuum manifold 116 is an ion source 118. During operation of the mass spectrometer 100, the transfer line 100 abuts the ion source 118, and the capillary column protected within the transfer line 100 protrudes from the outlet 114 thereof, extending into the ion source 118. The ion source 118 includes an input port 120. The input port 120 exhibits a generally conical shape. The capillary column is literally funneled into its proper position within the ion source 118 by virtue of its interaction with the conical input port 120.
Time-sequenced gaseous samples of an analyte are delivered from the capillary column into the ion source 118, whereupon the aforementioned analyte samples are ionized. The ionized samples are propelled through a mass analyzer (or, e.g., filter) to an ion detector (not shown). The mass analyzer (or, e.g., filter) is energized in such a way so as to establish an electromagnetic field. The electromagnetic field has the effect of permitting, at a given point in time, only ions with a particular charge-to-mass ratio to pass through the analyzer (or, e.g., filter) to the detector. To ensure that the gaseous samples do not interact with other molecules and thereby become contaminated, the interior of the mass spectrometer 102 is evacuated by a pump, so that a vacuum exists within the vacuum manifold 116 of the mass spectrometer 102.
The vacuum manifold 116 defines an orifice 122. A vacuum (gate, ball or other) valve 124 is joined to the vacuum manifold 116 at the orifice 122. A gasket (o-ring) 126 is interposed between the vacuum (gate, ball or other) valve 124 and the vacuum manifold 116, to create a seal between the two structures. As depicted herein, the vacuum valve 124 is presented as a gate valve. This need not be the case, and the vacuum valve 124 may be embodied as other forms of valves, such as a ball valve or other form of valve for preserving a vacuum. The vacuum valve 124 is depicted and discussed as a gate valve for the sake of illustration only.
The vacuum valve 124 has an inlet end 128 and an outlet end 130 (the vacuum valve 124 may be physically symmetrical, so that its inlet end 128 and outlet end 130 are defined by use, i.e., the outlet end 130 is the end of the vacuum valve 124 that is joined to the vacuum manifold 116). A passageway 132 runs through the body 134 of the vacuum valve 124, extending from the inlet end 128 to the outlet end 130. The vacuum valve 124 also includes a plate 136. As shown in
A load-lock adapter 138 is joined to the inlet end 128 of the vacuum valve 124. A gasket 140 is interposed between the load-lock adapter 138 and the vacuum valve 124, so as to create a seal between the two structures. The load-lock adapter 138 has an inlet end 142 and an outlet end 144 (in some cases, the load-lock adapter 138 may be physically symmetrical, so that its inlet end 142 and outlet end 144 are defined by use, i.e., the outlet end 144 is the end of the load-lock adapter 138 that is joined to the vacuum valve 124). A passageway 146 runs through the body 148 of the load-lock adapter 138, extending from its inlet end 142 to its outlet end 144.
The load-lock adapter 138 includes a pair of gaskets 150. Each gasket 150 is dimensioned to form an air-tight seal with the outer sheath 104 of the transfer line 100. Although the particular embodiment depicted in
As can be seen from
Next, as shown in operation 302, the vacuum valve 124 is closed. Thus, the outlet side of the passageway 132 through the vacuum valve 124 remains in fluid communication with the interior region of the vacuum manifold 116. However, the inlet side of the passageway 132 through the vacuum valve 124, the transfer line 100, and the load-lock adapter 138 are no longer in fluid communication with the interior region of the vacuum manifold 116. Thus, the load-lock adapter 138, transfer line 100 and the inlet side of the passageway 132 through the vacuum valve 124 may be vented (operation 304), while the operating environment within the mass spectrometer is preserved, e.g., the vacuum within the vacuum manifold 116 is not disturbed, nor is the temperature of the environment within the vacuum manifold disturbed. The venting operation 304 may occur through the ports 152, for example.
According to some embodiments, the ion source 118 may by joined to the distal end 110 of the transfer line 100. Thus, removal of the transfer line 100 from the mass spectrometer 102 according to the above-described method also results in removal of the ion source 118, without disruption of the operating environment within the mass spectrometer 102.
According to some embodiments, the ion source 118 may by joined to the distal end 110 of the transfer line 100. Thus, introduction of the transfer line 100 to the mass spectrometer 102 according to the above-described method also results in introduction of the ion source 118, without disruption of the operating environment within the mass spectrometer 102.
The various embodiments described above are provided by way of illustration only and should not be construed to limit the invention. Those skilled in the art will readily recognize various modifications and changes that may be made to the present invention without following the example embodiments and applications illustrated and described herein, and without departing from the true spirit and scope of the present invention, which is set forth in the following claims.
