JPH0336799Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention is a glass tube that is sandwiched between a relatively short axial end of a glass tube and a metal tube with a seal to prevent liquid leakage. It is applied to sight glasses, etc. that detect the presence or absence of liquid flow, flow velocity, etc.

(Prior art) A device has already been developed that seals a relatively short glass tube, such as a sight glass, by sandwiching both axial ends of the glass tube between metal tubes. As shown, the metal tubes b, b corresponding to both ends of the glass tube a are made slightly smaller in diameter, and the ring-shaped sealing pads e are fitted into the flanges c, c corresponding to the opposite ends of the glass tube a, respectively. d, put the seal gasket on the end face of the glass tube a, and screw the positioning nut g and tightening nut h on the glass tube a side to the threaded rod f passed through the flanges c and c on the outer periphery of the glass tube a. and positioning nut g
The corresponding spacing between the flanges c and c is determined, and the flanges c and c are tightened using a tightening nut h, and the sealing gasket e is compressed toward the end face of the glass tube a to form a seal. In principle, the device uses four threaded rods spaced at 90° intervals, and the flanges c and c are tightened using the tightening nut h of one threaded rod, and then the other three screws are tightened. When tightening the tightening nuts h on the rods, the tightening force may become unbalanced and damage the glass tube a, so the position of the positioning nut g on each threaded rod f should be adjusted so that the four rods can be tightened almost equally. As each tightening nut h must be turned little by little while adjusting the If there is an imbalance in the tightening force by the tightening nut h of f, the glass tube a
glass tube a is damaged, and the glass tube a has to be replaced and the tightening work has to be redone. The fundamental technical reason for this is that the end face of the glass tube a is tightened by the flanges c, c through the seal gasket e.

(Problems to be solved by the present invention) In view of the above, the present invention switches to a structure in which a threaded rod tightens the metal pipe flange in the approaching direction and an O-ring compresses the glass pipe from the circumference to seal it. The goal is to develop a possible configuration.

(Means for solving the problem) The purpose of the present invention is to specifically solve the problem mentioned in the previous section. An annular protrusion is provided on the flange that protrudes with a slight gap from the outer periphery of the glass tube, and the annular protrusion is engaged with steps on both sides of the threaded rod in the longitudinal direction to maintain the gap, and the flange is screwed onto the threaded rod. An O-ring corresponding to the outer periphery of the glass tube is fitted to the bottom of the receiving ring that is pressed into contact with the tightening nut, and a fitting groove is provided in which the annular projection is fitted.The O-ring compressed by the annular projection is inserted from the circumference of the glass tube. This invention relates to a glass tube attachment device characterized by pressure-welding and sealing.

A preferred embodiment of the invention will now be described.

(Example) Figures 1 and 2 illustrate a lantern-shaped sight glass as a typical example of sealing by sandwiching a glass tube between metal tubes. 1 is a relatively short glass tube;
2 is a metal tube that clamps the end face of the glass tube 1 in the axial direction, and is provided with flanges 3, 3 corresponding to the end face of the glass tube 1, and a small gap is placed between the flanges and the outer periphery of the glass tube 1. A fitting groove 6 is provided in which the annular protrusion 4 is fitted into the inner circumference of a receiving ring 5 that is loosely fitted around the glass tube 1.
Form into a shape that is open at the inner periphery.

7 forms step portions 8, 8 on both ends in the length direction to engage the receiving ring 5, and screws 9, 9 with small diameters at both ends thereof pass through the receiving ring 5 and the flange 3; The stepped portions 8, 8 are positioned so that the flanges 3, 3 which press against the receiving rings 5, 5 do not come into contact with the end surface of the glass tube 1, and the screws 9, 9 protruding from the flanges 3, 3. Screw the tightening nuts 10, 10 into the parts.

In this embodiment, the receiving rings 5, 5 are fitted into grooves 6, 6.
Fit the O-rings 11, 11 to the bottom of the metal tube 2, pass the screws 9, 9 of the threaded rod 7 so that the stepped portions 8, 8 engage with the receiving rings 5, 5, and then insert the flanges 3, 3 of the metal tube 2. through the screws 9, 9 and the annular protrusions 4, 4.
into the grooves 6, 6, then tighten the tightening nut 1.
0, 10 to the screws 9, 9, and the metal tubes 2, 2
Tighten the tightening nut 1, taking care to prevent the flanges 3 from touching the end faces on both sides of the glass tube 1.
Tighten by 0,10.

(Function) In the present invention, the flanges 3, 3 of the metal tubes 2, 2 are tightened by the tightening nuts 10, 10 of the threaded rod 7, and the O-rings 11, 11 advance the annular protrusions 4, 4 in the axial direction of the glass tube 1. is compressed by the annular protrusions 4, 4 and pressed against the outer periphery of the glass tube 1 to form a seal 12.

(Effects) The present invention has the above-mentioned configuration, and instead of clamping the flange 3 of the metal tube 2 to the end face of the glass tube 1 through a gasket as in the conventional method, the flange 3 of the metal tube 2 is pressed from the outer periphery toward the center with uniform pressure. It has a structure in which the seal 12 is applied by pressing only the O-rings 11, 11 onto the outer periphery of the glass tube 1, which has a high strength when pressed. The structure in which the flanges 3, 3 are provided with annular protrusions 4, 4 that loosely fit around the outer periphery and compress the O-rings 11, 11 fitted into the fitting grooves 6, 6 provided therein prevents the glass tube 1 from being damaged. metal tube 2, without
Although the number of parts increases slightly by using the receiving rings 5, 5, the number of assembly steps is reduced, and the assembly can be performed without requiring much skill. have.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional side view, and FIG. 2 is a plan view taken along line A--A in FIG. 1. FIG. 3 is a partially cutaway side view showing an example of a conventional device. 1...Glass tube, 2...Metal tube, 3...Flange, 4...Annular projection, 5...Receiving ring, 6...
Fitting groove, 7... Threaded rod, 8... Step, 9... Screw, 10... Tightening nut, 11... O-ring, 1
2...Seal.

Claims (1)

[Claims for Utility Model Registration] In a configuration in which both axial ends of a relatively short glass tube are sandwiched between metal tubes, the flange 3 of the metal tube 2 corresponds to the end of the glass tube 1 at a distance. An annular protrusion 4 is provided on the outer periphery of the glass tube to protrude with a slight gap therebetween, and is engaged with steps 8 on both sides of the threaded rod 7 in the longitudinal direction to maintain the gap, and the flange 3 is connected to the threaded rod 7. An O-ring 11 corresponding to the outer periphery of the glass tube 1 is fitted to the bottom of the receiving ring 5 which is pressed into contact with a tightening nut 10 which is screwed into the receiving ring 5 . A glass tube mounting device characterized in that a compressed O-ring 11 is pressure-welded from the circumference of a glass tube 1 for sealing.