JPH0329787A - Apparatus for preventing leakage from manhole for liquid storage tank - Google Patents

Abstract

PURPOSE:To ensure the prevention of leakage from manhole part and contrive the opening thereof with ease by a method wherein a manhole cover is provided with a cylindrical inner neck for insertion into a coaming, a neck receiver for contact engagement with the end of the inner neck is fixed to the inner peripheral surface of the coaming and an inner packing material is provided on the neck receiver to form a double packing structure. CONSTITUTION:A manhole cover 3 is provided with a cylindrical inner neck 5 having a somewhat smaller diameter than the inside diameter of a coaming 2. The coaming 2 has fixed to its inner peripheral surface an annulus ring-like neck receiver 6 having a L-shaped cross section and engageable with the end of the inner neck 5 and the neck receiver 6 is provided with an inner packing material 7 at the contacting part with the end of the inner neck 5. When the manhole cover 3 is fastened to the flange 2a of a manhole part X with a bolt and nut, the inner neck 5 is moved in the direction of the arrow A, whereby its end is forced against the neck receiver 6 via the inner packing material 7. Therefore, the manhole cover 3 is forced against the flange 2a at the end of the coaming 2 via a packing material 4 and, by such double packing structure, a high sealing effect can be obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a manhole leak prevention device for a liquid storage tank. [Prior Art] In tanks used for liquid storage, the following two leakage prevention structures are adopted to prevent the contents from leaking from the manholes, especially from the manholes provided on the side walls of the tank. .

In the normal type, the tank (1) is shown in Figure 3.
The manhole part X consisting of the coaming (2) protruding from the wall is closed with a manhole cover (3), and for this purpose, the flange part (2a) at the end of the coaming (2) is closed.
) and the manhole cover (3), a packing material (4) is interposed between them and the manhole cover (3) is tightened with bolts and nuts. Also, in the case shown in Fig. 4, a rib (10) is welded to the inner peripheral surface of the coaming (2), and a closing plate (1o) is further attached to the rib (1o).
1l) is welded to completely prevent leakage. [Problems to be solved by the invention] With the former leak prevention structure, many accidents occur where leakage occurs from the packing part due to material deterioration of the packing material (4) or poor tightening of bolts and nuts. Furthermore, in the latter leakage prevention structure, when the manhole cover (3) is removed to open the manhole section (1
), which requires a long construction period, and problems remain in terms of workability and safety.

The present invention was devised in view of the above-mentioned problems of the prior art, and provides a manhole leak prevention device that can reliably prevent leakage from a manhole and also allows the manhole to be easily opened. This is what we mean. [Means for Solving the Problems] Therefore, the manhole leak prevention device of the present invention improves the former leak prevention structure among conventional leak prevention structures to a double packing structure. That is, in a manhole leak prevention device for a liquid storage tank in which a packing material is interposed between the flange of the coaming end of the manhole and the manhole cover, a cylindrical pipe inserted into the coaming is attached to the manhole cover. The basic feature is that in addition to providing an internal neck, a neck receiver against which the tip of the internal neck comes into contact is fixed to the inner periphery of the coaming, and an internal packing material is further attached thereto, creating a double packing structure. In addition, the second invention employs the above-mentioned double packing structure, and in addition, an internal lid is fixed to the inner peripheral surface of the cylindrical internal neck, and the internal lid is deformed by hydraulic pressure during storage. The sealing force of the neck receiver against the internal packing material is increased without causing any displacement at the tip of the internal neck, thereby further enhancing the sealing effect of the double packing structure.

〔Example〕

Specific examples of the present invention will be described below.

FIG. 1 is a sectional view showing the structure of a manhole portion X of a liquid storage tank (1) equipped with a leakage prevention device according to an embodiment of the second invention. As shown in the figure, the manhole section
) A cylindrical coaming (2) protrudes from the wall surface, and this manhole part
2) A packing material (4) is inserted into the flange portion (2a) at the end, and the disk-shaped manhole cover (3) is closed by tightening bolts and nuts. Furthermore, on the above manhole cover (3), just combing (
A cylindrical internal neck (5) having a diameter slightly smaller than the inner diameter of 2) is provided. On the other hand, an annular neck receiver (6) with an L-shaped cross section is fixed to the inner circumferential surface of the coaming (2), and the neck receiver (6) has an L-shaped cross section and is in contact with the tip of the internal neck (5). An internal packing material (7) is attached to the abutting portion of the tip of the internal neck (5). Further, a disk-shaped inner cover (8) having the same diameter as the inner diameter of the inner neck (5) is fixed to the inner peripheral surface of the inner neck (5) closer to the manhole cover (3). In the leakage prevention device of this embodiment having the above-described structure, the manhole cover (3) is fastened with bolts and nuts to the flange portion (2a) of the manhole portion X, as shown in FIG.
The internal neck (5) moves in the direction of arrow A, and its tip end is pressed against the neck receiver (6) via the internal packing material (7). Therefore, the combing (2)
Since the manhole cover (3) is pressed against the end flange (2a) via the packing material (4) and the double packing structure is adopted, a higher sealing effect can be obtained.

Furthermore, when the stored liquid is put into the tank (1), liquid pressure Y is applied to the internal lid (8), so as shown by the imaginary line in Fig. 2, the manhole cover (3) The inner lid (8) will flex towards the side. Then, the internal neck (5) curves halfway toward the center of the inner cylinder, and its tip moves in the direction of arrow B in the figure. Due to this displacement of the tip, the seal pressing force of the neck receiver (6) against the internal packing material (7) is further strengthened, and the sealing effect becomes extremely high.

〔Effect of the invention〕

According to the configuration of the present invention described in detail above, since it has a double packing structure, the effect of preventing the contents from leaking from the manhole portion is enhanced, and when the manhole portion is opened, the manhole cover can be easily opened, which is an excellent effect. have. Further, according to the device structure of the second invention, by putting the stored liquid into the tank, the sealing effect of one packing part of the double packing structure is further enhanced, and a more remarkable effect can be obtained in preventing leakage of the content liquid. .

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the structure of a manhole portion of a liquid storage tank equipped with a leakage prevention device according to an embodiment of the second invention;
FIG. 2 is an enlarged sectional view of the manhole section, FIG. 3 is a sectional view showing the structure of the manhole section of a liquid storage tank equipped with a conventional leakage prevention device, and FIG. FIG. 2 is a cross-sectional view showing the structure of a tank manhole section equipped with a leakage prevention device. In the figure, (1) is the liquid storage tank, (2) is the combing, (
2a) is the flange part, (3) is the manhole cover, (4) is the packing material, (5) is the internal neck, (6) is the neck holder, (7) is the internal packing material, (8) is the internal cover, indicates the manhole section.

Claims (2)

[Claims] (1) A manhole of a liquid storage tank in which a packing material is interposed between the flange of the end of the coaming and the contact surface of the manhole cover when the manhole portion consisting of a coaming on the wall of the liquid storage tank is closed with a manhole cover. In the leak prevention device, the manhole cover is provided with a cylindrical internal neck that is inserted into the coaming, and a neck receiver is fixed to the inner periphery of the coaming to which the tip of the internal neck is abutted. A manhole leak prevention device for a liquid storage tank, further comprising an internal packing material. (2) A manhole of a liquid storage tank in which a packing material is interposed between the flange of the combing end and the contact surface of the manhole cover when the manhole portion consisting of a coaming on the wall of the liquid storage tank is closed with a manhole cover. In the leakage prevention device, the manhole cover is provided with a cylindrical internal neck that is inserted into the coaming, and a neck receiver is fixed to the inner periphery of the coaming, and the tip of the internal neck is abutted thereto. Further, an internal packing material is attached, and an internal lid is fixed to the inner circumferential surface of the internal neck, and the internal lid is deformed by the liquid pressure during storage, and this deformation causes a displacement at the tip of the internal neck, and the neck receiver is 1. A manhole leak prevention device for a liquid storage tank, characterized in that the seal pressing force against the internal packing material of the liquid storage tank is increased.