JP3573538B2 - Seismometer with signal cable test section - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a seismometer, and more particularly to a seismometer having a watertight test section at a signal cable connection thereof.
[0002]
[Prior art]
Underground seismometers and seafloor seismometers apply high water pressure to the seismometer according to the installation depth. For example, a water pressure of about 10 atm at a depth of 100 m, and about 50 atm at a depth of 500 m, and the signal cable and signal cable And will join.
In order to maintain the watertightness of the seismometer under this water pressure, the joint of the metal parts is usually sealed with an O-ring.
This O-ring is a standard product that has been industrially standardized, and if it is attached to a part that has been processed to the specified dimensions, a watertight seal can be reliably achieved and a highly reproducible sealing mechanism is constructed. It is.
[0003]
By the way, in the underwater seismometer, the watertight structure between the signal cable that takes out the signal from the seismometer main body and the seismometer main body does not have the shape with the dimensional accuracy like metal parts. mounting and manufactured conformance to sealing member has a structure that holds the watertight.
However, this watertight structure is poor in reproducibility unlike the O-ring method, and therefore, a test in the final shape is indispensable.
[0004]
Therefore, in the final water tightness test, put the seismometer main body (when the seismometer main body is large and cannot enter the water pressure tester, only the joint with the signal cable) into the water pressure tester (test container), and It is necessary to have a structure that can be pulled out while maintaining watertightness from the hydraulic test container.
In this case, if the length of the signal cable is short, it is possible to attach the cable and the watertight part to the mouth of the water pressure test container from the end of the cable. Since it is difficult to attach the watertight parts by any suitable means, the watertight parts are sealed with a half-split type sealing member or a half-split type water-resistant vessel lid.
[0005]
That is, as shown in FIG. 2, put the seismometer body 4 connected to the signal cable 7 to a water pressure resistance tester (test vessel) 1, split seal member supported a signal cable 7 to split type seal case 9 8, the container lid 2 of the test container 1 (the container lid 2 is composed of a pair of half-split lids 2a, and each lid 2a is watertightly attached to the opening of the test container 1 with a bolt 20). And high-pressure water is sent from the high-pressure pump connection part 3 attached to the vessel lid 2 to the inside of the test vessel 1 while monitoring a pressure gauge (not shown) until a specified water pressure is reached. While maintaining the main body 4 and the signal cable 7 within a specified water pressure, a water pressure resistance test of the seismometer main body 4 and a connection portion between the main body 4 and the signal cable 7 is performed.
[0006]
Here, a void 4a is formed in the seismometer main body 4, and in this void 4a, a seismometer sensor 5 composed of vibration sensors 5a, 5b, and 5c in the X, Y, and Z directions. Is installed, and a signal cable 7 is connected to each of the vibration sensors 5a to 5c.
At the connection between the signal cable 7 and the seismometer main body 4, a cable head 6 composed of a pipe structure is provided, and the signal cable 7 is inserted into a hollow portion 6 a of the cable head 6 as shown in FIG. The first cable seal member 11 and the second cable seal case member 12 in the watertight cable seal case 13 are held in the cable seal case 13 in a watertight manner.
[0007]
That is, the first cable seal member 11 has a tapered outer peripheral surface whose outer diameter decreases toward the inside of the seismometer main body (to the right in FIG. 3), and is tightened by the tightening bolt 11b via the tightening fitting 11a. When being tightened, the tapered outer peripheral surface of the first cable seal member 11 is pressed against the tapered inner peripheral surface of the cable seal case 13 so that the inner diameter portion is deformed inward and tightly contacts the signal cable 7, Keep the cables watertight.
Also, the inner diameter of the second cable seal member 12 is deformed inward by the tightening of the tightening member 12a screwed to the inner peripheral surface of the cable seal case 13, so that the signal cable 7 is kept watertight.
[0008]
The inner end (right end in FIGS. 2 and 3) of the hollow portion 6a of the cable head 6 communicates with the inner space 4a of the seismometer main body 4 as described above. A cable head cover 14 is screwed onto the outer end. Note By tightened the cable head cover 14, is pressed against the cable seal case 13 to the step portion 6b of the cable heads 6, it acts to retain the cable head 6 in the position shown. Reference numeral 16 in the figure indicates an O-ring provided in each water seal portion.
[0009]
[Problems to be solved by the invention]
By the way, in the above-mentioned conventional water pressure resistance test (machine), not only the structure is complicated, but also a divided part (half-split part) constitutes a watertight part, so that it is difficult to maintain watertightness. is there.
The present invention has been made to attempt is made to solve such a problem, after performing watertight test seismometer body, the signal junction is essential watertight test after cable connection (signal cable and seismometers body It is an object of the present invention to provide a seismometer having a signal cable watertight test section capable of independently performing a water pressure test without preparing a special tester only for a joint portion with a signal cable.
[0010]
[Means for Solving the Problems]
For this reason, the seismometer provided with the signal cable watertight test section of the present invention is installed in a place where high water pressure is applied, such as underground or on the sea floor, and an electric signal of a seismic wave detected by a seismometer sensor is extracted by a signal cable. An underground or seafloor seismometer, comprising: a seismometer main body; and a cable head that is watertightly attached to a lead-out portion of the signal cable of the seismometer main body and that holds the signal cable in a watertight manner. A water pressure test chamber for conducting a seal test between the signal cable and the cable head is formed at the cable outlet, and a space is provided for installing the seismometer sensor in the seismometer body. is, the cable head is at the inner end portion is constituted by a tubular structure having a hollow portion communicating with the cavity of the seismograph body, of the cable head Emptying unit, Rutotomoni cable seal case for inserting supporting the signal cable watertight is disposed in the watertight cable head cover for closing the outer end of the hollow portion in a watertight manner is attached, the signal cable is the cable the head cover through a watertight via the water pressure resistance test cable sealing member extending outward of said cable head, said water pressure resistance test chamber is formed between the cable seal case and the cable head cover The water pressure resistance test cable seal member, the outer shape is formed in a tapered shape in a direction that can withstand the water pressure from the water pressure resistance test chamber, and, with the tightening of the cable head lid, The inner end surface of the cable seal case is pressed against the step portion of the cable head via the cable seal member and the pressure receiving plate and positioned. It is characterized in that it is configured.
[0011]
Further, the present invention is the upper Symbol cable head cover, and a means of solving the problems with the water pressure resistance test chamber to form a high-pressure pump connection port connectable to a high-pressure pump.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a seismometer having a signal cable watertight test section as one embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of the cable head. In FIG. 1, the same reference numerals as those in FIGS. 2 and 3 denote substantially the same members.
[0013]
Also in this embodiment, the cable head 6 is formed of a tube structure having a hollow portion 6a, and a cable seal case 13 is attached to the hollow portion 6a by an O-ring 16 in a watertight manner. More corrugated medium opening of the cable seal case 13, the first cable seal member 11 and the second cable seal member 12 is attached respectively, as in the conventional example described above, each bolt 11b and clamping member 1 1 By tightening a, the signal cable 7 can be held watertight by the first and second cable seal members.
[0014]
A cable head cover 14 is screwed and attached to the outer end (the left end in FIG. 1) of the cable head 6, and an O-ring 16 is interposed between the cable head cover 14 and the cable head 6. The watertightness between the cable head cover 14 and the cable head 6 is maintained, and a water pressure test chamber 19 is formed between the cable seal case 13 and the cable head cover 14.
A high-pressure pump connection port 15 and a high-pressure water passage 15a are formed in the cable head cover 14 to supply a high water pressure to the water pressure test chamber 19 from a high-pressure pump (not shown).
[0015]
Further, in order to prevent the test water supplied to the water pressure test chamber 19 from leaking, a cable seal member 18 for the water pressure test is provided in the signal head 7 insertion portion of the cable head cover 14.
The water pressure resistance test cable seal member 18 has an outer peripheral shape formed in a tapered shape in a direction that can withstand the water pressure from the water pressure resistance test chamber 19, and when the cable head lid 14 is tightened, the root of the cable seal member 18 is formed. parts to the signal cable 7 while being pressed an outer peripheral surface of the tapered shape by Rukoto is pressed against the tapered inner circumferential surface of the cable head cover 14 with reduced diameter inner diameter portion by the pressure receiving plate 10 (right end in FIG. 1) They are in close contact with each other and keep the signal cable 7 watertight.
[0016]
The water tightness of the water pressure test chamber 19 is maintained by an O-ring 16 interposed between the cable head cover 14 and the cable head 6 and between the cable seal case 13 and the cable head 6.
By tightening the cable head cover 14, the cable seal case 13 is pushed against the step portion 6b of the cable head 6 via the cable seal member 18 and the pressure receiving plate 10, the inner end surface of the cable seal case 13 of the cable head 6 stages It is positioned in contact with the portion 6b and is held at the position (state) shown in FIG.
[0017]
In the above-described configuration, high-pressure water is supplied to the water pressure test chamber 19 through the high pressure pump connection port 15 formed in the cable head cover 14, and the water pressure test chamber 19 is maintained at a specified water pressure for a certain period of time, and the signal cable A confirmation test of water tightness between the cable seal case 7 and the cable seal case 13 can be performed.
In the case of an underground or ocean bottom seismometer, the sealing between the signal cable 7 and the cable seal case 13 is the most difficult, and therefore, it is the most necessary to check the seal at this point in the entire structure. In this case, the seal can be checked simply by preparing a pressurizing pump (including a pressure gauge).
[0018]
Therefore, the seal can be easily checked just before the seismometer is buried, and the reliability at the time of installation can be improved.
It goes without saying that this seal confirmation test is performed after the watertightness test of the seismometer main body.
[0019]
【The invention's effect】
As described above in detail, according to the seismometer provided with the signal cable watertight test section of the present invention, just by preparing a pressurizing pump (including a pressure gauge) immediately before embedding the seismometer, the entire seismometer can be obtained. A seal check test can be performed at the point where the sealability is required most in the structure, and the positioning of the cable seal case can be performed without any trouble, thereby improving the reliability of the seismometer at the time of installation. The advantage is obtained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a cable head of a seismometer provided with a signal cable watertight test section as one embodiment of the present invention.
FIG. 2 is a cross-sectional view of a conventional water pressure tester for a seismometer.
FIG. 3 is a sectional view of a cable head of the seismometer of FIG. 2;
[Explanation of symbols]
1 Water pressure tester (test container)
2 Waterproof pressure tester lid 3 High pressure pump connection 4 Seismometer main body 4a Vacancy formed in seismometer main body 5 Seismometer sensor 6 Cable head 6a Hollow portion of cable head 7 Signal cable 8 Split type cable seal member 9 Split type Cable seal case
10 Pressure plate
11 First cable seal member
11a Tightening bracket
11b Tightening bolt
12 Second cable seal member
12a Tightening member
13 Cable seal case
14 Cable head lid
15 High pressure pump connection port
15a High pressure water passage
16 O-ring
18 Cable seal for water pressure test
19 Water pressure test room

Claims (2)

Underground or seafloor seismometers that are installed in places under high water pressure, such as underground or on the sea floor, and that take out electric signals of seismic waves detected by seismometer sensors using signal cables, A cable head which is attached to the lead-out portion of the signal cable in a water-tight manner and which holds the signal cable in a water-tight manner; and a seal between the signal cable and the cable head is provided at a signal cable outlet of the cable head. test water pressure resistance test chamber is formed for performing said seismometers the seismometer sensor can be installed cavity in the body is formed, the cable head, the cavity of the seismograph body at the inner end It consists of a tubular structure having a hollow portion communicating with, the hollow portion of the cable head, the cable seals inserted supporting the signal cable watertight With over scan is disposed in watertight, the outer end portion of the hollow portion cable head cover is attached to closed watertightly, watertightly the signal cable through the cable sealing member for a water pressure resistance test the cable head closure through to extend outwardly of the cable head, said water pressure resistance test chamber be formed between the cable seal case and cable head cover, said water pressure resistance test cable seal member, the outer periphery thereof It is formed in a tapered shape in a direction that can withstand the water pressure from the water pressure test chamber, and, along with the tightening of the cable head lid, the inside of the cable seal case via the cable seal member and the pressure receiving plate. and an end face configured to be positioned pressed against the stepped portion of the cable head, a signal cable watertight test unit Withered was seismometer. 2. The seismometer according to claim 1 , wherein a high-pressure pump connection port capable of connecting the water-resistant test chamber to a high-pressure pump is formed in the cable head lid.

Images