JPH0242421B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The disclosed technology belongs to the field of hydraulic sealing technology for pipe ends used for hydraulic pressure testing and hydraulic expansion of various pipes.

<Summary of the gist> The invention of this application is a pipe end hydraulic sealing device used for pressure resistance tests of pipe bodies and hydraulic pipe expansion, in which a main body of the sealing device is tightly press-welded to the entire circumference of the end of a pipe to be set. This invention relates to a pipe end hydraulic sealing device which has a supply/exhaust cavity for supplying pressurized fluid to the inside of the pipe and is tightened between frames via a tie rod. is fixed, and a plunger having a ring-shaped stepped portion with a cross-sectional area not smaller than the cross-sectional area of the tube is inserted into the cylinder so as to be able to move forward and backward. This invention relates to a pipe end hydraulic sealing device in which a pressure fluid supply/exhaust cavity is provided in the inside of the plunger, extending over the seal portion, for feeding the pressure fluid from the cylinder into the pipe.

<Prior art> As is well known, piping is widely used in many industrial fields, and depending on its use, pressure resistance and corrosion resistance are particularly required. Corrosion-proofing treatments such as water pressure pipe expansion and other measures are being carried out.

This type of work on the tube requires a hydraulic sealing device at the end of the tube since considerable hydraulic pressure acts inside the tube.

The general form of a conventional hydraulic sealing device for pipe ends is as shown in FIG. The frames 4, 4 at both ends are pressed together via the tie rods 5, 5 to seal them, the water inlet 6 of one frame 4 is closed, and the water inlet 6 of the other frame 4 is connected to a predetermined area. High-pressure water is fed into the pipe under pressure to carry out specific tasks.

<Problems to be Solved by the Invention> However, in the above-mentioned conventional pipe end hydraulic sealing device, as the pressure of the pressure water supplied into the pipe 1 increases, the cross-sectional area S of the pipe 1 increases. The pressure P x S, which is the pressure P applied to the frame 4, is applied as an axial force to the frame 4, and as a result, the tie rod 5 stretches, which reduces the sealing function of the seal 3. However, there was a problem that leakage occurred, and the specified pressure resistance test and tube expansion could not be achieved.

To deal with this, it is possible to increase the preload of the packing 3 and keep the tension of the tie rod 5 sufficiently large, but in this way, the pipe 1
When the wall thickness of the tube 1 is thin or the length of the tube 1 is large, there are problems such as buckling deformation of the tube 1 due to an excessive compressive load applied to the tube 1.

In addition, the design thickness of the tube 1 to be used for the final purpose does not match the thickness of the tube 1 during processing, and as a result,
It also had the disadvantage of high cost.

<Purpose of the Invention> The purpose of this application is to solve the problem of the sealing of the pipe end hydraulic sealing device based on the above-mentioned prior art, while making the thickness of the pipe the same as the thickness of the pipe intended for final use. It is also possible to apply a predetermined hydraulic pressure,
Moreover, it is an object of the present invention to provide an excellent pipe end hydraulic sealing device that can reliably seal and prevent buckling deformation and the like, thereby benefiting the field of piping technology used in various industries.

<Means and operations for solving the problem> In order to solve the above-mentioned problem, the structure of the invention of this application, which is based on the above-mentioned claims, is to provide a cylinder of a frame fixed by a tie rod. The tube end of the tube is inserted into the cylinder, and the tube end is set in contact with the tube end seal portion of the plunger facing the liquid chamber of the cylinder, and the tube end is connected to the plunger through the connection between the plunger end and the seal jaw. The cylinder is brought into watertight contact, a predetermined pressure fluid is supplied from the cylinder, and the pressure fluid is applied to the inside of the pipe through the pressure fluid supply and drainage cavity of the plunger to perform a predetermined work. During this time, the axial force due to the pressure inside the pipe increases as the applied hydraulic pressure increases, but the hydraulic pressure applied to the ring-shaped stepped part with a cross-sectional area equal to or larger than the cross-sectional area of the plunger of the sealing device main body in the cylinder is equal to the axial force. By increasing the size of the plunger, the seal at the end of the pipe is reliably maintained and there is no leakage, and the rod of the hydraulic cylinder fixed to the frame is able to fit into the plunger. The tube end sealing part is fixed to the bracket of the pipe to further ensure the sealing of the pipe end sealing part.

<Example> Next, an example of the invention of this application will be described below based on FIGS. 2 and 3.

Note that the same parts as in FIG. 1 will be explained using the same reference numerals.

In the embodiment shown in FIG. 2, reference numeral 7 denotes a pipe end hydraulic sealing device which constitutes the gist of the invention of this application, and is used for sealing the pipe end 2 of the pipe 1. Although only one end is shown, in reality, the other end (not shown) is also provided, and the frames 4', 4' are connected and connected by tie rods 5, 5, . . .

A hydraulic cylinder 9 is fixed to the inside of the frame 4' via bolts 8, 8', and inside the cylinder 9 is a conductor connected to a high-pressure water pump (not shown). Liquid chamber 1 via water port 6'
0 is formed.

Reference numeral 11 denotes a plunger, which forms a ring-shaped stepped portion 12 with a set depth in the radial direction in the liquid chamber 10, and its small diameter base side is liquid-tight so that it can freely slide around the cylinder 9 via a packing 3'. It is inserted into.

The cross-sectional area of the ring-shaped stepped portion 12 is set to be equal to or larger than the cross-sectional area S of the tube 1.

On the other hand, the large-diameter portion of the plunger 11 is slidably inserted into the cylinder 9 through a packing 3'' in a watertight manner, and a flange portion 1 is provided on the base end side of the cylinder 9.
A tapered portion 14 is formed through the tube end 3 to form a tube end sealing portion that abuts the flare 15 formed at the tube end 2 of the tube 1 all around in a watertight manner.

A seal 16 is divided into two parts in the circumferential direction, contacts the flare 15 of the pipe 1 from the back side, is removably fastened to the flange 13 of the plunger 11 via bolts 8, and connects the flare 15 to the taper of the seal. It is adapted to be pressed and tightened by the portion 14.

A pressurized fluid supply/exhaust cavity 17 is formed inside the plunger 11 , which faces the interior of the pipe 1 from the tapered portion 14 and communicates with the fluid chamber 10 of the cylinder 9 .

In the above configuration, the tube end 2 of the tube 1 is connected to the tapered portion 14 of the sealing portion of the plunger 11 by appropriate means.
The flare 15 is formed into a tapered shape that matches the above, and is brought into contact with the taper part 14 of the plunger 11 that freely slides into the cylinder 9 in the draining state, and the seal jaw 16 is brought into contact with the taper part 16 from the outside. 8 to the flange portion 13, the pipe end 2 of the tube 1 is fastened to the taper portion 14 of the seal portion of the plunger 11 in a watertight state all around.

Then, by pressing a start switch (not shown), the high pressure water pump is operated via a switching valve (also not shown), and high pressure water is fed into the liquid chamber 10 of the hydraulic cylinder 9 from the water introduction port 6'.

The fed high pressure water is then sent to the hydraulic cylinder 9.
The liquid is supplied from the liquid chamber 10 to the supply/exhaust cavity 17 of the plunger 11, and is supplied to the inside of the pipe through this to be subjected to a predetermined hydraulic test or hydraulic pipe expansion.

Then, as the pressurized water pressure gradually increases, an axial force of P×S acts on the plunger 11 as a reaction force against the pressure P acting on the cross section S, where the cross-sectional area of the pipe 1 is S.

However, in the invention of this application, the annular cross-sectional area of the ring-shaped stepped portion 12 of the plunger 11 located in the liquid chamber 10 of the hydraulic cylinder 9 of the plunger 11 is equal to or larger than the cross-sectional area S of the pipe 1. By this design, the pushing force in the direction of the tube 1 in the liquid chamber 10 can be made to be substantially equal to or greater than the above-mentioned axial force, and therefore the strength of the tube 1 can be increased. Combined with this, the plunger 11 does not move left or right.

Therefore, there is no risk that the sealing of the seal portion 14 of the plunger 11 against the flare 15 of the tube 1 will become loose or that a leak will occur as a result.

On the other hand, as the water pressure inside the pipe 1 increases, its diameter expands and becomes larger, and the axial length contracts accordingly, since the seal jaw 16 is securely clamped to the plunger 11 via the bolt 8. In addition, the plunger 11 slides toward the tube 1 and is retracted, so that the seal against the flare 15 is not weakened and no leakage occurs.

Therefore, the water pressure test and the water pressure expansion of the pipe 1 are reliably performed.

During this time, leakage from the liquid chamber 10 of the hydraulic cylinder 9 is reliably prevented by the gaskets 3' and 3''.

When the predetermined work is completed, the switching valve (not shown) is switched to drain the water from the water inlet 6'.
Alternatively, remove the water pressure, remove the bolts 8, dissociate the seal jacket 16 from the flange 13, and remove the pipe 1 from the plunger 11.

In addition, in this embodiment, the ring-shaped stepped portion 12
By making the cross-sectional area of the pipe 1 larger than the cross-sectional area S of the pipe 1 by a designed amount, the plunger 11 is always
It is also possible to actively ensure a seal by pressing the tube 1 in the direction of the tube 1 by a set pressure.

Further, in this case, it is necessary to design the tube 1 to such an extent that buckling deformation does not occur.

As a design change, a hydraulic cylinder may be used instead of the tightening bolt 8 of the seal jaw 16.

Various design changes are also possible, such as attaching the tube end hydraulic sealing device 7 to one end of the tube and simply using a pressure sealing device at the other end.

Further, in the embodiment shown in FIG. 3, the plunger 11'
The tube end 2 of the tube 1 is brought into contact with the seal at the proximal end of the frame 4' through the packing 3.
A predetermined number of hydraulic cylinders 18, 18, .
A hydraulic circuit 22 from the hydraulic cylinder 18 is connected to an oil tank 25 via a switching valve 23 and a hydraulic pump 24.

In this embodiment, pressurized water from the water inlet 6' of the cylinder 9 is supplied and discharged from the liquid chamber 10 to the end of the pipe 1 which is in contact with the end of the plunger 11' via the packing 3, as in the above embodiment. The plunger 11' is introduced into the pipe 1 through the cavity 17, and the same operations as described above are performed, except that the plunger 11' is set and reset relative to the pipe 1 by the action of the respective hydraulic cylinders 18, 18 provided on the frame 4'. The driven fine pressure adjustment is performed, and the plunger 11' can be moved forward and backward minutely in response to fluctuations in the water pressure on the pipe 1.

In this embodiment, it is also possible to change the design so that the pressure of the hydraulic cylinder is adjusted appropriately via an automatic adjustment device while detecting the water pressure of the supply/discharge cavity 17 in the plunger 11'.

<Other Embodiments> It goes without saying that the embodiments of the invention of this application are not limited to the above-mentioned embodiments. Adoptable.

<Effects of the Invention> As described above, according to the invention of this application, basically, in a pipe end hydraulic sealing device used for hydraulic pressure testing and hydraulic expansion of pipes, high pressure liquid is fed into the pipe, and as a result, the Even if the tube expands in the radial direction and contracts in the axial direction, the tube end seal is always tightly pressed to ensure a complete seal, so that no leakage of the applied pressure fluid occurs, and the tube remains intact. An excellent effect is achieved in that the hydraulic pressure does not change even if the fluid is deformed in the radial and axial directions.

Therefore, the precision of the manufactured pipe products is improved, and the excellent effects of good management are achieved.

Since the seal for the seal at the end of the tube is formed at the tip of the plunger that can slide freely relative to the cylinder fixed to the frame, the plunger always smoothly follows the expansion and contraction behavior of the tube. This provides an excellent effect of stably maintaining a seal against the end of the tube.

In particular, by connecting the sealing jaw at the tube end to the end of the plunger, the tube end can be reliably clamped, and the plunger can be allowed to move even when the tube is contracted in the axial direction.

In addition, because a pressure fluid supply/exhaust cavity is formed inside the plunger for the fluid chamber in the cylinder and the seal at the end of the tube, the plunger remains stable even though it slides following the expansion and contraction of the tube. The excellent effect of applying pressure liquid is achieved.

Furthermore, since the rod of the hydraulic cylinder provided on the frame is connected to the bracket of the plunger, not only is the setting and resetting of the pipe smoothly and reliably performed by the hydraulic cylinder, but also the pipe is An excellent effect is also achieved in that the pressure can be adjusted by the hydraulic cylinder when a fluctuation occurs in the plunger while the plunger follows and supplies pressurized liquid.

The plunger has a ring-shaped stepped part in the cylinder, so that the cross-sectional area of the ring-shaped stepped part can be made equal to or larger than the cross-sectional area of the tube by a set amount, so that the pressure can be improved. Although the plunger follows the axial deformation of the pipe, the axial force is large and does not apply to the plunger.In fact, it is possible to prevent it from being applied at all, or even apply a slight pressure, making it more reliable. The excellent effect is that the seal is maintained.

[Brief explanation of the drawing]

FIG. 1 is an explanatory sectional view of a pipe end hydraulic sealing device based on the prior art, FIGS. 2 and 3 are explanatory views of an embodiment of the invention of this application, and FIG. 2 is a longitudinal sectional view of one embodiment. FIG. 3 is a longitudinal sectional view of another embodiment. 2... Pipe end, 17... Supply and drainage cavity, 10... Liquid chamber,
7, 7'... Seal device body, 5... Tie rod,
4,4'...Frame, 9...Cylinder, 11,
11'...Plunger, 14...Seal portion, 12
...Ring-shaped stepped portion, 17...Pressure fluid supply and drainage cavity, 20
...rod, 21...bracket, 1...tube.

Claims (1)

[Scope of Claims] 1. In a pipe end hydraulic sealing device in which a sealing device main body which is in pressure contact with the entire circumference of a pipe end and has a pressure fluid supply and drainage cavity is provided on a frame fixed to a tie rod, a cylinder is attached to the frame. is fixedly installed, a tube end sealing portion is provided at the proximal end of the plunger that is inserted into the liquid chamber of the cylinder, and a ring-shaped stepped portion having a cross-sectional area not smaller than the cross-sectional area of the tube is provided inside the cylinder of the plunger. A pressurized fluid supply/exhaust cavity is formed in the plunger and communicates with the fluid chamber of the cylinder and the sealing portion, and a seal at the end of the tube is connected to the end of the plunger. Features: Pipe end hydraulic seal device. 2. In a pipe end hydraulic sealing device in which the sealing device main body, which is pressed against the entire circumference of the pipe end and has a pressure fluid supply/exhaust cavity, is provided on a frame fixed to a tie rod, a cylinder is fixed to the frame, and A tube end sealing portion is provided at the proximal end of the plunger that is inserted into the liquid chamber of the cylinder, and a ring-shaped stepped portion having a cross-sectional area not smaller than the cross-sectional area of the tube is provided inside the cylinder of the plunger. A pressurized fluid supply/exhaust cavity is formed in the plunger and communicates with the fluid chamber of the cylinder and the seal portion, and a rod of the hydraulic cylinder provided on the frame is connected to a bracket provided on the plunger. A pipe end hydraulic sealing device characterized by: