CN86208798U

CN86208798U - Pressure-differential pore gauge with adjustable range

Info

Publication number: CN86208798U
Application number: CN 86208798
Authority: CN
Inventors: 苏恺之
Original assignee: CRUSTAL STRESS RESEARCH INST STATE BUREAU OF SEISMOLOGY
Current assignee: CRUSTAL STRESS RESEARCH INST STATE BUREAU OF SEISMOLOGY
Priority date: 1986-11-07
Filing date: 1986-11-07
Publication date: 1987-09-09

Abstract

The utility model discloses a pressure-differential pore gauge with adjustable range. The probe head of the utility model is provided with the heavy oil, and the probe head can directly transfer the pressure of the liquid to measure to one end of the differential pressure switch and can reduce the loss of the pressure transmission; an electromagnetic valve is arranged in the probe head; the pressure difference of both ends of the differential pressure switch becomes zero when the electromagnetic valve is opened in the short-time, and the utility model has not only high resolution but also large measuring range; a heat resistance thread which can calibrate the calibration of the probe head at any moment is arranged beneath the probe head. The utility model can widely apply to the precise observation to the rock mass or the earth body pore water pressure in the deep drilling, and the obtaining of the new observation data in the geological engineering or the geo-science study.

Description

Pressure-differential pore gauge with adjustable range

The utility model belongs to the pore pressure surveying instrument.

Existing type vibration wire pore pressure cell, in probe, vibrating wire pressure sensor is housed, treat during use that the pressure of fluid measured acts on the outside surface of probe, and testing pressure is delivered to vibrating wire pressure sensor by its internal mechanical structure or liquid, hole fluid pressure to be measured is measured in variation by sensor output, make the pore pressure cell of this structure, range is little when resolution is high, and range when big resolution low, the ratio of resolution and range is generally at per mille～per mille point about five.Nineteen eighty-three has been introduced this kind product that Soil Loss testing tool company limited produces on the proceeding of international rock mechanics second session that the U.S. holds, when range is 8 MPas, resolution is 0.015 MPa, and resolution is per mille point nine with the ratio of range.

The pressure of liquid carries out precision and observes at present all needing blowhole in ROCK MECHANICS RESEARCH, soil mechanics research still are work such as earth science research or in the soil body hole, many measurements are carried out in deep bores again, 100 meters of the every increases of wellbore depth, just require range to increase by 1 MPa, therefore require pore pressure cell both to have high resolving power, has enough big range again, and above-mentioned type vibration wire pore pressure cell can't carry out the measurement of high precision and large measuring range, the utility model is made a kind of high resolving power, wide range pore pressure cell according to actual needs.

Adopt differential sensor in the utility model probe, it is inner that hole liquid to be measured flows directly into probe, and directly acting on the interior heavy oil of probe, the pressure of heavy oil changes the upper end that directly acts on the differential pressure pickup in the probe, has reduced the loss during pressure transmits; Solenoid valve is housed in the probe, when solenoid valve is of short duration open after, can make the pressure reduction at differential pressure pickup two ends revert to zero, the range of instrument is regulated automatically, so this instrument had both had high resolving power, have wide range again, the ratio of resolution and range is several ten thousand/in addition higher.Thermal resistance wire is equipped with in probe below, according to the i.e. normal pressure value that provides of probe below as can be known of the heating power of thermal resistance wire and heat time heating time, can demarcate instrument at any time.

Of the present utility model further specifying by following examples and accompanying drawing provides.

Fig. 1 is for implementing and be installed in the pore pressure cell in rock stratum or the soil layer boring, (1) probe among the figure, (2) cable according to the utility model, (3) boring in rock stratum or the soil layer, the water-bearing zone of (4) boring, the sleeve pipe that (5) are provided with at the crushing rock formation band, (6) stopper, (7) solid water shutoff mud.

Fig. 2 is the pore pressure cell probe profile of implementing according to the utility model, comprises that diameter is 95 millimeters, thick 5 millimeters stainless steel garden tube shell (8), lower end cap (9), loam cake (10), porous filtering chamber (11), upper spacer (12), lower clapboard (13) and cable (2).

Fig. 3 is the pore pressure cell probe sectional view of implementing according to the utility model.The top of probe internal partition (12) is porous filtering chamber (11), lower clapboard (13) is divided into probe upper chamber (14) and lower chambers (15) again, be full of heavy oil (16), (17) in upper chamber (14) and the lower chambers (15), differential pressure pickup (18) is housed on the lower clapboard (13), solenoid valve (19), thermal resistance wire (20) and insulation rod (21).

Testing liquid enters water inlet (23) by porous filtering chamber (11) and copper mesh (22), act on the heavy oil (16) in the upper chamber (14), the pressure of heavy oil (16) changes the upper end (24) that directly acts on differential pressure pickup (18), the lower end (25) of differential pressure pickup (18) communicates with lower chambers (15), the difference of the normal pressure value of the force value of heavy oil (16) and heavy oil (17) converts electric signal to by differential pressure pickup, reaches surface instrumentation through cable (2).When pressure differential surpasses a certain setting (less than differential pressure pickup self range), provide control signal by surface instrumentation, open once solenoid valve is of short duration, the pressure reduction that makes upper chamber (14) and lower chambers (15) is zero, hydraulic pressure total variation in the step variable quantity that sensor provides when opening is for the previous period.No matter pressure has much magnitudes to change, and this measuring system can both normally be followed the tracks of work, and can keep the fixed sensitivity of weighing apparatus, and when sensitivity was 20 MPas, best range was 10 MPas.

By measuring the heating power and the heat time heating time of thermal resistance wire (20), can demarcate the normal pressure value of the heavy oil (17) in the lower chambers (15) at any time.

Claims

1, a kind of pore pressure cell, it is characterized in that popping one's head in interior upper spacer (12) top is porous filtering chamber (11), lower clapboard (13) is divided into probe upper chamber (14) and lower chambers (15) again, and be full of heavy oil (16), (17), the pressure differential of the heavy oil (17) in the heavy oil (16) in the upper chamber (14) that causes by testing liquid and the lower chambers (15), be converted to electric signal by differential pressure pickup (18), measure by surface instrumentation.

2, a kind of pore pressure cell according to claim 1, its feature also is to be equipped with on the lower clapboard (13) thermal resistance wire (20), by measuring the heating power and the heat time heating time of thermal resistance wire (20), can demarcate the normal pressure value of heavy oil (17) in the lower chambers (15) at any time.

3, a kind of pore pressure cell as claimed in claim 1 or 2, its feature also are to be equipped with on the lower clapboard (13) solenoid valve (19), when solenoid valve is of short duration open after, can make the pressure reduction at differential pressure pickup two ends revert to zero, the range of instrument is regulated automatically.