US3174344A - Fluid sample introducing device for a gas chromatograph - Google Patents

Description

FLUID SAMPLE INTRODUCING DEVICE FOR A GAS CHROMATOGRAPH Filed March 12, 1962 2 Sheets-Sheet 1 March 23, 1965 TATSURO HARUKI FLUID SAMPLE INTRODUCING DEVICE FOR A GAS CHROMATOGRAPH 2 Sheets-Sheet 2 Filed March 12, 1962 United States Patent FLUID SAMPLE INTRGDUCING DEVICE FOR A GAS CHROMATOGRAPH Tatsuro Haruki, Nara-ken, Japan, assignor to Kahushilri Kaisha Shimazu Seisakusho, Kyoto, Japan, a company of Japan Filed Mar. 12, 1962, Ser. No. 178,864 Claims priority, application Japan, Mar. 18, 1961, 36/ 9,636, 36/ 13,736 1 Claim. (Cl. 73-422) This invention relates to a fluid sample introducing device of a gas chromatograph.

Automatically operating devices for introducing liquid sample in gas chromatographs are already known. However, in such devices, the prior known expedients for controlling flow of the sample into the gasifying chamber do not provide a positive enough out-off and thus gasification of the sample continues and in the chamber prevents one from obtaining a sharp separation of the peaks as can be obtained when the samples are injected manually.

The main object of the present invention is to provide a device wherein such defects are eliminated.

Further, another object of the present invention is to provide a sample introducing device wherein samples can be automatically and repeatedly injected into the gasifying chamber by means of a programmer without any manual troubles and the amount of the sample introduced in one charge can be increased.

In order to attain the above objects, according to the present invention there is provided a fluid sample introducing device of a gas chromatograph comprising a cylinder device for picking up and pouring out of the sample, a sample injecting part to pour the sample from the cylinder device to the sample introducing chamber of the gas chromatograph, a means to operate the sample injecting part so as to advance it into the sample intro ducing chamber to take a pouring position and then retract it from the chamber to take a shut-oif position and an automatically repeating system to regulate the operation of the cylinder device and the sample injection part in the order of the picking up of the sample by the cylinder device, the advance of the sample injecting part into the sample introducing chamber, pouring of the sample and the retraction of the injecting part to the shut-01f position from the sample introducing chamber.

These objects and features will be clarified by the following description and by the accompanying drawings in which:

. FIG. 1 is a diagrammatic view of an embodiment of the present invention;

FIG. 2 is a vertical section view of the sample introducing chamber and the sample injection part to be utilized in the device shown in FIG. 1.

With reference now to FIG. 1, the sample introducing device provides a-cylinder device 1, the sample introducing chamber 2 i.e. a sample evaporating chamber, a

sample leading pipe 3 and a carrying plunger 4 for advancing and retracting the end of the sample leading pipe 3 or the sample injecting part with respect to the sample gasify-ing chamber. When the end of the pipe 3 is in the retracted position, the end of the pipe must be cut oii from the space within the gasifying chamber. In order that this cut-off or shut-01f may be simply accomplished, a spring loaded valve is arranged in front of the plunger so as to normally close the gasifying chamber and is pushed open by the plunger when the plunger advances together with the pipe to pour in sample liquid. However, any other proper cut-01f means may be sepa rately operated.

The cylinder device 1 consists of a cylinder 5 and a 3,174,344 Patented Mar. 23, 1965 plunger 6 so as to take the sample from the sample reservoir '7 and to feed it out. M and M are electric motors. The motor M is provided to operate the cylinder device 1 through an operatively connecting mechanism 8 including cams which operate to open and close a group of contacts 9. The motor M serves to operate the plungers 4 through an operatively connecting mechanism 10 including cams and to open and close contacts 11. The cylinder device 1 is so made as to simultaneously pour the same amounts of a fluid sample into four parallelly arranged gasiliying chambers. However, in the drawing, While all tour of the sample leading pipes 13, 3', 3 and 3" are shown, only the gasifying chamber for the pipe 3 is shown. When an introduction order is thrown into a switch SW shown in the right lower pant of the drawing and the switch is thus temporarily closed, the operation of the cylinder device 1 and plunger 4 will begin and will automatically proceed as described in the following.

(I) Suction of the sample When the switch SW is temporarily switched to the right in the drawing by the introduction order, a discharging current of a condenser will flow through a relay coil R and a switch SW will be closed. Thereby, a circuit through an electric current source line L relay coil R sWitch SW n-0rm-ally closed contact NC (O)coil S of an electromagnetic valve V-elec-tr-ic current source line L will be closed and the electromagnetic valve V will open. The switch SW will be directly opened but a switch SW will be closed by the action of the coil R and there-tore the energiZ-a-tion of the coil S will be continued. When the switch SW closes as mentioned above, a circuit through the electric current source line L coil R switch SW switch SW -con-trol coil P of the motor M switch SW -electric current source line L will be also closed, the motor M will start and the operatively connecting mechanism 8 will begin to operate. When the operatively connecting mechanism 8 has operated to lower the plunger 6 by a fixed amount, said mechanism will open the. contact NC (0) through the cams, therefore then the motor M will stop and the electromagnetic valve V will close.

(2) Insertion of the inlet pipe end into the gasifying chamber The opera-tively connecting mechanism 8 will close the normally opened cont-act NO (1) at the same time when it opens the contact NC (0) as mentioned above. Thereby a circuit through the electric current source line L -switch SW control coil P of the motor M switch SW -normally closed contact NC (5)contact NO (1)electric current source line L will be closed, therefore the motor M will start and the operatively connecting mechanism 10 will begin to operate. When the operatively connecting mechanism 10 has opera-ted to advance the plunger 4 and to make the inlet pipe end come into the gasifying chamber, said mechanism will open the contact NC (5) through the cams, then the motor M will stop and therefore the inserting operation will be stopped.

(3) Pouring in the sample At the same time when the operatively connecting mechanism 10 opens the contact NC (5) as mentioned above, it will close the normally opened contact NO (6). Thereby a circuit through the electric current source line L relay coil R contact NO (6)normally closed contact NC (2)-electric current source line L will be closed, the relay coil R will be energized, therefore the switches SW and SW will be switched and the circuit of the control coil F will be closed with the polarity reversed. The motor M will be thereby reversed and the sample will be poured in.

(4) Ron-action of the inlet pipe end When a fixed amount has been poured in as mentioned above, the operatively connecting mechanism 8 will close the normally opened contact NO (3) and therefore a circuit through the electric current source line L relay coil R -normally closed contact NC (4)contact NO (3)electric current source line L will be closed. Thereby the relay coil R; will be energized, the switches SW and SW will be switched and the motor M will reverse. The relay coil R which has reversed the motor M by switching the switches SW and SW will stop the motor M as the contact NO (6) which has been closed is opened by the reverse of the motor M When the motor M has reversed and the operatively connecting mechanism 10 has operated to retract the inlet pipe end to the fixed position, the contact NC (4) will open and the energization of the relay coil R will be stopped. Thereby the switches SW and SW will be switched back to the illustrated state and the motor M will stop.

The device will thus complete one cycle of the pouring operation and will be ready to receive an introduction order coming to the switch SW In the device according to the present invention, as explained in the above, the inlet port end is advanced into and retracted from the sample introducing part and is cut ofi, the separation of the peak even in the case of handling a large amount of the sample can be improved and an efiicient analysis is made possible by making the whole operation automatic. The device is adaptable specifically to separated gas chromatographs.

The detailed construction of an example of the part of the sample introducing chamber is shown in FIG. 2 and the part will be explained with respect to this figure.

In FIG. 2, 21 is a gasifying chamber, 22 is a cylinder and 23 is a plunger which corresponds to the plunger 4 of FIG. 1 which corresponds to chamber 2 in the schematic of FIG. 1. The cylinder 22 is fixed at the forward end to the wall of the gasifying chamber 21. The plunger 23 within the cylinder 22 supports a sample leading pipe 24, corresponding to lead-in pipe 3 of FIG. 1, as extended forward from its top part. 25 is a valve for closing the gasifying chamber and is pressed by a spring 26 against a valve seat 27 so as to separate the space within the gasifying chamber 21 and the space in front of the plunger 23 within the cylinder 22 from each other. When the plunger 23 is moved rightward in the drawing by a lever 28, this lever 28 being part of the mechanism 10 shown in FIG. 1 by which operation of the plunger 4 (23) is obtained from motor M2, the top surface 29 of the plunger 23 will advance while pressing the valve body 25 on the tail end 30 so as to push open the valve body 25 against the force of the spring 26 and to advance the end part of the sample leading pipe 24 supported by the plunger into the gasifying chamber. The sample will be poured in such state and will be delivered onto a metal screen 32 heated by a heater 31. In such case, a drain hole 33 made in the cylinder 22 will be closed against the gasifying chamber 21 by means of a packing ring 34 fitted to the plunger. When the plunger 23 is then retracted by the lever 28, the valve body 25 will be again seated on the valve seat and will close the gasifying chamber. The sample dropping from the end of the retracted sample leading pipe will fall into a receiver 35 through the drain hole 33.

36 is a carrier gas leading pipe. 37 is a flow path leading to a column. 38 is a rubber plate for introducing samples by an injection needle. 39 is a cap for retaining said rubber plate.

The above described device according to the present invention is characterized in that, when the end of the sample leading pipe has advanced into the sample leading part and has delivered a fixed amount of the sample, it will be directly retracted and the cutoff of the sample feed from the gasifying chamber will be very sharp. Thereby it can be prevented that the sample will continue to be gasified from the end of the leading pipe such that the peaks will not separate well.

What I claim is:

Apparatus for introducing a fluid sample into the sample chamber of a gas chromatograph comprising, a cylinder device including a cylinder and a plunger, a sample leading means for feeding the fluid sample delivered from said cylinder device to a sample introducing chamber of said gas chromatograph, an automatically closing valve controlling access to said sample introducing chamber, a holding member which holds said sample leading means and which is arranged to advance the discharge end of said sample leading means and to push and open said automatically closing valve thereby placing said discharge end in communication with said chamber, a first reversible motor for operating the plunger of said cylinder device, a second reversible motor for operating said holding member to advance and retract the discharge end of said sample leading means and to open said valve, a first relay for reversing a first polarity control coil of said first motor, a second relay for reversing a second polarity control coil of said second motor, a first normally closed contact provided in the circuit of said first control coil and which is opened to stop said first motor by a cam driven by that motor when the suction stroke of said plunger is terminated, a second normally open contact provided in the circuit of said second control coil and which is closed to start said second motor by a cam driven by said first motor when said first contact is opened, a third normally closed contact provided in the circuit of said second control coil and which is opened to stop said second motor by a cam driven by said second motor when said discharge end of said sample leading means reaches said advanced position, a fourth normally open contact provided in the energizing circuit of said first relay and which is closed by a cam driven by said second motor when said third contact is opened, a fifth normally closed contact connected in series with said third contact and which is opened by a cam driven by said first motor when the delivery stroke of said plunger is terminated, a sixth normally open contact provided in the energizing circuit of said second relay and which is closed by a cam driven by said first motor when said fifth contact is opened, and a seventh normally closed contact connected in series with said sixth contact and which is opened by a cam driven by said second motor when said discharge end of said sample leading means reaches its retracted position.

References Cited by the Examiner UNITED STATES PATENTS 7/63 Martin et a1. 73-422 OTHER REFERENCES RICHARD C. QUEISSER, Primary Examiner,

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