Pressure vessel

Abstract: A pressure vessel comprising a hollow cylindrical member and a cylindrical body section slidably fitted into the cylindrical member, the body section being formed as an integral member consisting of disc-like end-wall sections provided at its ends and a middle section which is cut out along two planes which are substantially parallel to the axial direction to define a specimen accommodating space. This structure allows for a simplified strength calculation during the design of a high-pressure vessel and provides an enlarged specimen accommodating space.

Description: BACKGROUND OF THE INVENTION Field of the Invention This invention relates to a pressure vessel used under high operating pressures (19.6 to 29.4 MPa) (200 to 300 kg/cm²G), such as an extraction vessel which constitutes the main equipment of an apparatus for executing supercritical extraction. Description of the Prior Art The applicant of the present invention previously invented a pressure vessel and filed a patent application for it JP-A-63-158396, hereinafter referred to as "prior art invention"). As shown in Figs. 4 and 5, the pressure vessel of this prior art invention comprises a cylindrical member a constituting the housing of the vessel, and two covers b respectively fitted into openings provided at both ends of the cylindrical member a , the two covers b being connected to each other through the intermediary of tie rods c to form an integrated unit which is slidable within the cylindrical member a . As shown in Fig. 5, the integrated unit of the above-described prior art invention is formed by connecting the two covers b by means of three tie rods c . However, this results in a cross section which is asymmetrical in the vertical direction. Consequently, calculation of the structural strength of a high-pressure vessel, which is an indispensable aspect of the design thereof, is inevitably rather complicated. If the tie rods c are connected to the covers b by means of screw sections d , as shown in Fig. 7, the screw sections d must be designed to be large. This, however, affects the strength. To cope with this, it is necessary for the overall structure to have a considerable size. This, in turn, results in the thickness t of the whole being rather too large. If, as shown in Fig. 8, large screw holes e are provided in the covers b and the covers b and the tie rods c are connected to each other by means of nuts f , the engagement sections will influence the strength, so that thickness t of the covers b has to be large. Moreover, it is not easy for gaskets g alone to effectively seal the screw sections. It might be considered possible to connect the tie rods c to the covers b by means of welding, as shown in Fig. 9. However, it is not possible for the welded sections h alone to withstand the great load imposed on them by the high pressure involved. US-A-3 411 655 discloses a structure in which end wall portions and a middle portion of a cylindrical body section are separable from another. Accordingly, this known device requires to perform troublesome assembling and disassembling works using bolts or the like upon assembling or maintenance of this pressure vessel. Additionally, there may be wear with respect to the annular recess or grooves and the corresponding flanges of the middle portions. Moreover, this known device requires extra work, such as control of bolts fastening torque, periodical exchange of bolts and closely checking the degree of wear of the connection portions of the respective parts. SUMMARY OF THE INVENTION It is accordingly an object of this invention to eliminate the problems experienced with the above-described prior invention of the type in which the covers b,b at the ends thereof are integrated with each other by means of the tie rods c , and to provide a pressure vessel which facilitates strength calculations and which includes a large accommodating space. This object is solved by a pressure vessel as claimed in claim 1. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view of the body section of the pressure vessel of this invention; Fig. 2 is a sectional view taken along the line II-II of Fig. 1; Fig. 3 is a sectional view showing the state in which a basket is lodged in the specimen accommodating space of the body section; Fig. 4 is a schematic view illustrating the prior art invention; Fig. 5 is a perspective view of the body section in the prior art invention; Fig. 6 is a sectional view showing the state in which a basket is lodged in the specimen accommodating space of the body section in the prior art invention; and Figs. 7 to 9 are views illustrating connecting structures provided between the tie rods and the covers. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of this invention will now be described with reference to the attached drawings. Fig. 1 shows a body section 1 of a pressure vessel in accordance with this invention. The body section 1 is composed of end-wall sections 1a,1a which correspond to the covers b in the prior art invention and connecting sections, 1b,1b which correspond to the tie rods c of the same. The connecting sections 1b,1b are formed integrally with the end-wall sections 1a,1a and are defined, as shown in Fig. 2, by two parallel planes 1c,1c along which the cylindrical body constituting the body section 1 is cut out to provide a configuration which is symmetrical in the vertical direction. The cross-sectional area of the connecting sections 1b,1b left after cutting out along the parallel planes is equal to the sum of the cross-sectional areas of the tie rods c in the prior art invention. Fig. 3 shows the state in which a gauze basket 4 containing specimens 3 is lodged in a specimen accommodating space 2 of the body section 1, which is inserted in this condition into the cylindrical member. Fig. 6 shows the way the specimens are set in the pressure vessel of the prior art invention. The presence of the tie rods c thus renders the specimen accommodating space very narrow, whereas the specimen accommodating space 2 of this invention is considerably large, the connecting sections 1b,1b playing the role of the tie rods c . Furthermore, the vertically symmetrical configuration obtained by cutting out the cylindrical body along the parallel planes 1c,1c allows for a simplified strength calculation which can be easily done during the design of pressure vessels. In addition, since the end-wall sections and the connecting sections are integrally formed, no such connecting problems as mentioned with respect to the prior art invention are involved.

Claims: A pressure vessel comprising a hollow cylindrical member and a cylindrical body section (1) slidably fitted into said cylindrical member in the axial direction, said body section (1) consisting of disk-like end-wall sections (1a) provided at its ends and a middle section defining a hollow section (2) between said end-wall sections (1a), characterized in that said body section (1) is an integral member and said middle section comprises two connecting sections (1b) in the form of sectors, obtained by cutting-out along two planes (1c) parallel to the axial direction and along two planes parallel to said end-wall sections (1a).

Inventors: HIRAOKA EIICHI, ONAKA JUNJI, HIRAOKA, EIICHI, ONAKA, JUNJI
Applicants: SUMITOMO HEAVY INDUSTRIES, SUMITOMO HEAVY INDUSTRIES, LTD
Application year: 1989
Main classification: B01D11
IPC codes: F16J12, F16J13, F16J1, B01J3, B01D11