TECHNICAL FIELD

The present invention relates to a storage tank, and a material vaporization device and a liquid material supply device provided with the storage tank.

BACKGROUND ART

Semiconductor manufacturing processes include one in which a liquid material supplied from a liquid material supply device is vaporized by a material vaporization device and led out to a chamber, and one in which a solid material is vaporized by a material vaporization device and led out to a chamber, and as a material storage tank of each device used in these semiconductor manufacturing processes, Patent Literature 1 discloses one including: a tank main body that stores a material; and a cover body that covers an opening of the tank main body, and having a structure to tighten a flange and the cover body by placing the cover body on the flange provided at the opening end of the tank main body and tightening tightening members passed through through-holes penetrating through the flange and the cover body.

However, in the material storage tank disclosed in Patent Literature 1 above, if the thickness of the flange is thin, the flange is deformed by tightening the tightening members, which causes the problem of being unable to maintain the contact property of the cover body with the flange, and only a tank main body provided with a flange having a certain level of thickness can be used.

Meanwhile, since a tank main body used for a conventional material storage tank for semiconductor manufacturing processes is structured by bending multiple plate materials made of metal or the like along the outer shape of the tank main body and mutually welding the multiple plate materials to connect them together, on the inner surface thereof, welding traces extending in a direction to intersect with the liquid level of a liquid material inevitably remain and the lower parts of the welding traces are in a state of being constantly exposed to the liquid material, so that there has been the problem that corrosion starts from here to reduce the strength of the tank main body. In addition, there has also been the problem that when the corrosion starts, corroded parts peel off from the inner surface of the tank main body and are mixed in material gas as particles to adversely affect respective devices connected to the downstream side of the tank.

Therefore, in order to eliminate welding traces caused when shaping a tank main body and extending in the up-down direction with respect to the liquid level of a liquid material while suppressing manufacturing cost, the applicant has attempted a method that stretches a plate material along the outer shape of the tank main body for shaping; however, the tank main body shaped by such a method has faced the problem of inevitably making the thickness of a flange thin to fail to use the structure to attach the cover body on the flange, which is employed by the material storage tank disclosed in Patent Literature 1 above.

CITATION LIST

Patent Literature

[Patent Literature 1]

Japanese Patent No. 5323654

SUMMARY OF INVENTION

Technical Problem

Therefore, the main problem of the present invention is to, even when the thickness of a flange provided at an opening edge of a tank main body is thin, attach a cover body on the flange while maintaining a contact property.

Solution to Problem

That is, a storage tank according to the present invention includes: a tank main body that stores a storage object consisting of at least any one or both of liquid and a solid; a cover body that covers an opening of the tank main body; a support body that is positioned opposite to the cover body; and a tightening member that tightens the cover body and the support body, in which the tank main body is provided with a flange at an opening end thereof, and the cover body and the support body are tightened by the tightening member in a state of sandwiching the flange.

In such a configuration, even when the thickness of the flange is thin, the sealability between the tank main body and the cover body can be maintained without deforming the flange. Accordingly, as the tank main body, one shaped by stretching a plate material made of metal or the like to make the thickness of the flange thin can also be used, and as a result, the tank main body becomes difficult to corrode.

Also, the storage tank may be one such that the cover body and the support body are tightened by the tightening member on the outer side than the outer edge of the flange.

In such a configuration, a tightening force by the tightening member is not locally applied to the flange, and as a result, a tightening force by the cover body and the support body can be substantially uniformly applied to the entire flange to improve the degree of sealing of the cover body with respect to the flange.

Further, the storage tank may be one such that the tightening member is a screw protruding from a position on the outer side than the outer edge of the flange in any one of the cover body and the support body, the other of the cover body and the support body is provided with a screw hole to be inserted with the screw, and the cover body and the support body are tightened by tightening of the screw into the screw hole.

In such a configuration, even when the thickness of the flange is thin, the sealability between the flange and the cover body can be maintained to be high without processing the flange having low strength. Also, only by changing the degree of tightening of the screw, the sealability of the cover body with respect to the flange can be easily adjusted.

Still further, any of the above-described storage tanks may be one further including a seal body that is sandwiched by the cover body and the flange.

Yet further, the storage tank including the seal body may be one further including a spacer that is sandwiched by the cover body and the support body, in which the spacer is thicker than the thickness of the flange and thinner than a thickness obtained by adding the thickness of the seal body in a non-pressurized state to the thickness of the flange, and further, in the surface opposite to the flange, the cover body has a holding groove that holds the seal body.

In such a configuration, the seal body can be prevented from being exceedingly squashed in a pressurized state, and also when the flange is tightened by the cover body and the support body, the circumferential surface of the flange can be tightened with uniform force. Further, the displacement of the seal body with respect to the flange and the cover body can be prevented.

Any of the above-described storage tanks may be one such that the tank main body is integrally shaped.

In such a configuration, no welding trace remains on the inner surface of the tank main body, and therefore corrosion resistance to material is remarkably improved to extend a durable period.

Also, a material vaporization device including any of the above-described storage tanks may be one including: a heater that heats the storage object stored in the tank main body; a lead-out pipe that is provided to the cover body to lead gas produced by vaporizing the storage object out of the tank main body; and a flow rate control device that is connected to the lead-out pipe.

Further, a liquid material supply device including any of the above-described storage tanks may be one including a lead out pipe that is provided to the cover body to lead the storage object consisting of liquid out of the tank main body.

Advantageous Effects of Invention

According to the present invention, even when the thickness of the flange provided at the opening end of the tank main body is thin, the cover body can be attached on the flange while maintaining a contact property.

