JPS5913289B2 - Hydraulic pipe expansion device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Conventionally, when joining a pipe and a tube sheet, etc., there is a purely mechanical device called an expander, which inserts the pipe into the tube sheet and expands the ends of the tube from the inner surface to join them.

All of this involves mechanically pushing and expanding the tube ends, but the following requirements are still required for this.

In other words, (1) the tube must be forcefully expanded mechanically against the tube sheet, but the mechanism is simple and easy to operate; (2) the airtightness and adhesion between the tube and the tube sheet; (3) Minimize damage to the inner surface of the tube during tube expansion; (4) Expansion joints can be made even on tubes with large wall thicknesses relative to the diameter; (5) Uniformity for many types of processing. (6) It is possible to simultaneously expand multiple pipes. However, it is nearly impossible for conventional expanders to meet all of these five requirements.

In view of these circumstances, the present invention performs pipe expansion using ultra-high hydraulic pressure instead of purely mechanical pipe expansion.
This has been put into practical use and has a value of '0, which fully satisfies the above requirements.

This will be explained using the illustrations. Reference numeral A denotes a device operating section, 1 is a pressure booster, 2 is a joint, and 3 is a switch handle.

B is a tube expansion part fixed to the device operating part A. Expanded tube part B
Pipe Expansion No. 5 The head 5 is provided with a hydraulic pressure communication hole 6 that communicates with the pressure intensifier 1 of the device operation section A, and this communication hole 6 is opened to the outer surface at approximately the center of the pipe expansion head 5. A surface portion 6' is formed. There is a through hole 7' in the center of the opening surface 6'.
A spacer 90-T having a shape is fitted.

O-rings 8, 8 are brought into contact with both sides of the spacer 7, and a backup ring 9/,
9 will be provided. 18 is a stepped wall of the tube expansion head 5 that supports this backup ring 9.

The backup ring 35 is made of steel, and the backup ring 9 is made of soft metal or an elastic body, and the contact surfaces thereof are inclined.

The back-up spring 9 shown in FIG. 3 is made of steel and is formed into a collet shape with notches 16 provided at several locations.

I will describe its effects.

Insert the end of the tube body 11 into the through hole of the tube sheet 10, and press the device operation part A.
The liquid is released by grasping the switch handles 3, 3 with both hands, inserting the expanded pipe part B fixed to the tip into the end of the pipe body 11, and rotating the switch handle 3 to operate the pressure intensifier 1. The pressure passes through the joint 2 and reaches the opening surface 6' from the flow hole 6 of the tube expansion section B, where the tube body 11 is expanded relative to the tube plate 10 and the two are joined.

The liquid pressure produced by the pressure intensifier 1 is an extremely high pressure of several thousand K9/~.degree.

At that time, the fluid pressure is sealed by O-ring 8, but this O
In contrast to the ring 8, the back-up spring 9 is made of a soft metal or an elastic body, so that the ring 9 undergoes plastic deformation to cover the increase in the gap between it and the tube body 11. Since the back-up spring q is made of steel, the O-ring 8 is not lifted upward even if the back-up spring 9 is plastically deformed, and its sealing is guaranteed. In the one shown in FIG. 3, the back-up spring 9 itself is made of steel and therefore does not undergo plastic deformation, but its notch 16 can compensate for the increase in the gap.

*Sadness The present invention uses ultra-high pressure to join the tube sheet and the tube body, and can do this with extremely simple operation, and does not damage the inner surface of the tube, compared to the conventional method. Even thick pipes that cannot be joined using a purely mechanical expander can be joined in a single operation. Furthermore, airtightness after expansion is guaranteed, numerous processing operations can be performed completely uniformly, and even if the tube has a wide expansion width, the tube can be expanded in a single operation.

In the present invention, in particular, an elastically deformable back-up spring is brought into contact with the outside of the back-up spring made of steel so that the O-ring is in direct contact with the O-ring, as shown in FIG. The O-ring is pushed outward by the hydraulic pressure and the steel back-up spring expands the elastically deformable back-up spring.
The O-ring is prevented from protruding, and the O-ring's liquid tightness is always ensured.

Therefore, there is no possibility that the O-ring will be cut due to its protrusion, and the tube expansion head can be easily removed after the tube is expanded. The experimental data for pipe expansion and joining using this device is listed below.

(Data 1.) Tube material...Boiler. Alloy steel tube for heat exchanger (STBA-24)

[Brief explanation of the drawing]

FIG. 1 is a front view of the entire device, FIG. 2 is a longitudinal cross-sectional side view of the tube expansion section, and FIG. 3 is a perspective view of an elastically deformable back-up spring. Further, FIG. 4 is a drawing for explaining the operation. B...
・Pipe expansion part, 1... Pressure booster, 5... Tube expansion head, 6... Distribution hole, 6''... Opening surface part, 8... ...0 ring, 9...elastically deformable back-up spring, 97...steel back-up spring, 16...notch.

Claims (1)

[Scope of Claims] 1. The tube expansion head of the tube expansion section is provided with a communication hole that communicates with the pressure intensifier, and the communication hole is opened on the outer surface of the tube expansion head at a substantially central portion to form an opening surface on the outer surface. Then, an O-ring is installed on both sides of the opening, and a steel backup ring is installed on the outside of the O-ring between the stepped wall provided on the tube expansion head and a back-up ring made of steel.
Hydraulic tube expansion device equipped with an elastically deformable backup ring on the outside. 2. The hydraulic pipe expansion device according to claim 1, which uses a collet-shaped steel backup ring with a notch as the elastically deformable backup ring.