JPH0510608B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a measuring device for measuring physical quantities in a sealed tank.

Physical quantities such as the temperature and density of the liquid in a sealed tank must be constantly or periodically measured for its management. Conventionally, the means for measuring the above-mentioned physical quantities is to place multiple detection elements within the tank. Because they are fixed in position, if there are multiple detection elements, it takes a lot of effort to maintain and manage the accuracy of each detection element, which is inefficient, and it is difficult to remove and inspect each detection element. There was a problem.

Furthermore, when an extremely low boiling point liquid such as liquid natural gas (hereinafter referred to as LNG) is stored in a tank, phases may be formed due to differences in the composition of the LNG, heat exchange, etc. Generally, in such a multicomponent system, when the density of the upper layer is higher than the density of the lower layer, a rollover phenomenon occurs in which the layers are reversed. When this rollover phenomenon occurs, extremely low boiling liquids rapidly generate vapor gas due to phase mixing. In order to prevent such a rollover phenomenon, it is necessary to measure the temperature, density, and other physical quantities of the liquid stored in the tank, and to detect and process the measured quantities. The specific method of measurement is to raise and lower the probe that detects the physical quantity from a fixed point on the bottom of the tank toward the liquid level.
Processes measurement results such as temperature density of tank storage liquid,
it's shown.

Conventionally, the method of raising and lowering a probe is to drive a hollow spiral drive cable fixed to one end of the probe by a stepping motor in a sealed housing installed on a tube body equipped with a shutoff valve on the tank roof. When the probe lands, a limit switch detects the change in force caused by implantation. In order to prevent the probe from swinging when raising and lowering the probe, anchors fixed to the two ribbon cables are suspended from the sealed housing onto the tank floor, and the tensioned ribbon cables are used as guides to ensure safety.
Furthermore, when inspecting the probe, the probe is housed in the sealed housing and the shutoff valve is closed to isolate the inside of the tank from the sealed housing.

When the conventional method described above is applied to a large tank, there is a problem in terms of safety. That is, first, the weight of the drive cable becomes much larger than the weight of the probe, and the detection sensitivity for detecting the landing of the probe decreases, making it impossible to obtain an accurate reference value. Second, the tension of the ribbon cable used to guide the probe needs to be increased according to the height of the tank, which increases the weight of the anchor, and with a simple hoisting method, it would damage the tank floor due to inertia. there's a possibility that. Third, it is difficult to make the lengths of the two ribbon cables equal and to properly place the anchor. Such problems can occur, for example, when a measuring device whose purpose is to prevent the dangers associated with rollover phenomena is inadequate, which can lead to serious disasters that defeat the original purpose. There was a problem with the noise.

Purpose The present invention has been made for the purpose of solving the problems in the prior art as described above and providing an in-tank physical quantity measuring device that is excellent in safety and measurement accuracy.

Configuration FIG. 1 is a configuration diagram of main parts for explaining one embodiment of the present invention, in which an operation case is connected to a connecting pipe 7 that vertically penetrates the upper surface TT of the tank 6 and is fixed through a valve mechanism 56. A body 8 is provided. The operation housing 8 includes a first lifting device that lifts and lowers a cylindrical probe 20 containing a built-in detector for detecting physical quantities such as temperature and density inside the tank 6 via a signal cable 22, and a first lifting device that lifts and lowers the probe 20 at the bottom of the tank. A second elevating device is installed to raise and lower the guide cable 5 that guides the guide cable 5 so that it can be raised and lowered without swinging on a vertical line at a fixed point. The valve 56 is for completely blocking the gas in the tank 6 from flowing into the operation housing 8 when the anchor 1 and probe 20 are initially stored in the upper connecting pipe 71 or during inspection. , the normal case of measuring is open. Although the sealing device 62 is always released, it prevents the gas in the tank from flowing into the operation case 8 when inspecting it with the valve 56 open, and allows the operation case 8 to be opened to the atmosphere. The details are shown in FIGS. 4 and 5. Guide cable 5
is a main element of the present device and its purpose is simply to guide the probe 20, so it may be fixed unless inspection is required. In the present invention, the anchor that tensions the guide cable 5 is made to have a double structure, which is made in accordance with this purpose, so that the anchor is semi-fixed so that a constant tension is always provided. This prevents damage to the bottom of the tank. Furthermore, the anchors are suspended via pulleys so that the two guide cables 5 are always tensioned with equal tension. The upper limit detector 65 detects the upper limit of the cylindrical probe and regulates the upper limit position. The upper limit detector 67 detects the upper limit of the anchor 3 and regulates the upper limit position. Additionally, an interlock feature is provided to prevent the anchor from being raised or lowered when the probe is not in the upper limit position.

Next, a structure for tensioning the guide cable 5 as described above will be explained with reference to FIG. 2. The second elevating device uses a drive motor 19 as a drive source, and rotates the winding drums 12, 12 via a torque limiter 54 and a drive shaft 18. The winding drums 12, 12 are arranged coaxially with the drive shaft 18, and one end of the guide cables 5, 5 is fixed to the winding drums 12, 12, respectively, and is wound thereon.
The guide cable 5 forms a loop with an intermediary roll 11, a guide roll 10, a pulley 4, a guide roll 10, and an intermediary roll 11 in this order. The pulley 4 is attached to a frame 3, and the anchor 1 is attached to the frame 3. The anchor 1 has a double structure consisting of cylindrical bodies 1a and 1b divided into two in the vertical direction, and the lower anchor 1a is provided with a plurality of guide rods 2 parallel to and symmetrical to the axis of the cylindrical body. The upper anchor 1b is provided with a through hole 1 axially symmetrical so that the guide rod 2 can be guided and slid within a predetermined range.
b' is provided, and the frame body 3 is different from the upper anchor 1.
Only b is fixed. Guide roll 10, 10
A component force of the weight of the anchor 1 acts on each of them.
This force is detected as a change in the amount of displacement of the spring 16 attached to the other point of force of the lever 14 having the fulcrum 13, with the axis of the guide rolls 10, 10 as one force point, and this amount of displacement is It is converted into an amount of electricity by a transformer 17 or the like.

According to the method described above, the guide cable 5 is connected to the pulley 4
The posture of the anchor is stable because it is always tensioned with the same tension by the anchor. When the anchor 1 reaches the tank floor LL, the tension of the lower anchor changes, so this amount of change is detected by the differential transformer 17 as a change in the analog amount,
This stops the anchor from lowering. Since the upper anchor 1b is guided by the guide rod 2,
The pulley does not swing, and therefore the guide cable 5 is stable in a predetermined position and tensioned with a constant tension by the upper anchor 1b. The part that is landed in this way is the lower anchor 1a. Since this change in weight can be reduced to an amount that can be stably detected by the differential transformer 17, it is possible to select a change that does not damage the floor surface of the tank.

The probe 20 is moved up and down along the guide cable 5 by passing the guide cable 5 through guide tubes 21 provided on both sides of the probe 20.
This probe 20 is driven by a first lifting device disposed within the manufacturing casing 8. That is, the signal cable 22 connected to one end of the top of the probe 20 is sequentially connected to the guide roll 24 and the detection roll 2.
5. It is raised and lowered by the winding roll 26. Also,
The winding roll 26 is rotationally driven by a drive motor 48 via a torque limiter 54 and a drive shaft 49. The amount of elevation of the probe is detected by a second detector 55 that detects the rotation of the rotation axis of the detection roll 25 using the upper surface of the upper anchor 1b as a reference position. The signal cable is a signal wire inserted into a spiral tube, and in order for the amount of movement of the signal cable to be properly rotated and transmitted by the detection roll 25 without slipping, the signal cable is connected to the detection roll 25.
It is inserted between pressing rollers that are pressed by the action of a spring 28. As mentioned above, the reference position of the probe is the top surface of the upper anchor, but this reference position is determined by changing the tension of the signal cable 22 in the same way when it is detected that the anchor has landed on the ground. be. That is, probe 2
0 and a weight proportional to the length of the signal cable 22 acts on the guide roll 24, but this force is generated by using the guide roll as one force point and attaching the spring 44 to the other force point of the lever 42 having the fulcrum 41. Then, the displacement of the spring is converted into a displacement amount, and this displacement amount is detected as an electrical quantity by the differential transformer 45.

FIG. 4 shows a state in which the cable is sealed, and FIG. 5 is a sectional view taken along the line V-V in FIG. 4, and shows a state in which the seal is released. Therefore, the fourth
In the figure, 61 is a part of the wall of the tank, 64 is a mounting base for the sealing device, and 66 is an inert gas supply pipe connected to an inert gas supply device (not shown). Thus, the sealing device 62 consists of sealers 80 and 80' made of substantially the same components,
These sealers 80, 80' each include a housing 81, 81', a rear plate 82, 82', a fixed seal member 83, 83', a front plate 84, 84', and an operating shaft 8.
5, 85', sliding members 86, 86', movable seal members 87, 87', washers 88, 88', retaining ring 8
9, 89', guide pins 90, 90', cover bodies 91, 91' of the pin driving part, and others. Note that since the configurations of these sealers 80 and 80' are substantially the same, only the sealer 80 will be described here.

Inside the casing 81, a small diameter circular hole through which the signal cable 22 is inserted and a slightly larger diameter circular hole perpendicular to the small diameter circular hole are provided.
It is closed by a rear plate 82 and a front plate 84. The operating shaft 85 has a threaded portion 85a and a sliding member mounting portion 85.
b, has a groove portion 85c for attaching a retaining ring, and has a threaded portion 8;
5a is screwed into a screw hole provided in the center of the front plate 84. The sliding member mounting portion 85b is rotatably inserted into an insertion hole provided at the center of the sliding member 86, and is locked by a retaining ring 89 so that its tip does not slip out of the insertion hole. The sliding member 86 is slidably fitted into the housing 81, and has an elongated guide groove 86 for the guide pin 90 on its side surface.
a, and is prevented from rotating by the guide pin 90, so that when the operating shaft 85 is rotated in either the forward or reverse direction by a rotating device (not shown), such as a manual handle or a DC motor, It is moved left and right in the figure depending on the direction of rotation.

Thus, as shown in FIG. 5, the fixed seal member 8
3 and the movable seal member 87 have half-moon-shaped notches 83a, 87a, respectively, and the fixed seal member 8
3 is fixed to the rear plate 82 with bolts 92, and the movable seal member 87 is attached to the sliding member 86 with bolts 93, 93.

To release the seal on the signal cable 22 from the sealed state shown in FIG. 4, rotate the operating shaft 85 and move the movable seal member 87 to the left in the diagram shown in FIG. Move it to the end. In such a case, the signal cable 22 is released from the half-moon notches 83a and 87a of the fixed seal member 83 and the movable seal member 87 and returns to its neutral position.
It can be raised and lowered freely using a winding winch, chain block, etc. (not shown). Therefore, when the predetermined work is completed, the operating shaft 8
5 in the opposite direction, and the movable seal member 87 is moved to the right end of the movement as shown in FIG. In such a case, the fixed sealing member 83 and the movable sealing member 87 constitute a barrier wall perpendicular to the axis of the signal cable 22 in the space between the signal cable 22 and the housing 81, and the signal cable 22 is held between the semicircular notches 83a and 87a of both seal members, and is inserted into the circular hole formed by both the notches. That is, in the above embodiment, the two sealers 80 and 80' form a pair of blocking walls. The sealing members inside each sealing device 80, 80' are fixed sealing members 83, 83' and movable sealing members 87, 8, each having a semi-cylindrical notch that can form a through hole for a wire or the like when abutted against each other.
7', operating shafts 85, 85', and sliding member 8.
6, 86', guide pins 90, 90', etc., slide the movable seal members 87, 87' within the housings 81, 81', and the fixed seal member 8
3 and 83'.

Note that if the through-hole for the wire, etc. formed by both seal members is provided at a position a small distance away from the neutral position of the wire, etc. toward the fixed seal member, when the seal is released, the wire, etc. will not be inserted into the seal device. It is possible to completely eliminate friction between the sealing mechanism and the sealing mechanism without making it come into contact with anything. If the fixed seal member 83 and the movable seal member 87 are made of tetrafluoroethylene resin, nylon, rubber, or other relatively soft materials or elastic members, the tank can be sealed in the sealed state shown in FIG. Although the gas, steam, etc. inside can be almost completely sealed, the two sealers 80, 8
A more complete seal can be achieved by forming seal portions at two locations using 0', connecting the inert gas supply pipe 66 to the intermediate portion, and performing purging with the inert gas. By this inert gas purge, not only the inside and outside of the wire etc. but also the operating shafts 85, 8
Although leakage from the threaded portion 5' is also prevented, it is also recommended to use other known sealing devices in this area.

In addition, in cases where the danger level of liquefied gas vapor is low, or when the sealing device is large, only one sealing device is used instead of two, and the inert gas supply pipe 66 is used for this gas purge. It is also possible to move it to a position 66' indicated by a dotted line in the figure. In this case,
The seal portions are provided on both sides of the opening of the inert gas supply pipe 66'.

FIG. 6 is a diagram for explaining another embodiment, in which 67 is a device for sealing the wire 68, 69 is a mounting base, and 70 is an inert gas supply pipe. The sealing device 67 includes a main housing 101 and a drive unit housing 10.
2. Packing 10 used as a sealing member
3, 103, distance piece 104 forming a seal pipe control device, spacer 105, packing set screw 106, worm wheel 107, worm gear 108, worm gear rotating shaft 109, bearings 110, 111, and rotation stop key 112
Consists of etc. The wire 68 passes through the main housing 105, and inside the main housing 105, packings 103, 103 surround the wire 68 to form a seal.
This seal portion is formed at two locations with the distance piece 104 in between, and is pressed by a packing set screw 106 via a spacer 105. The worm wheel 107 is rotated by a worm gear 108, and the packing set screw 108 is raised and lowered in accordance with the rotation direction of the worm wheel 107. When the packing set screw 106 is moved downward in the figure and the packing 103, 103 is air-conditioned, the packing 103, 103 is moved to the wire 68.
The space between the wire 68 and the main housing 101 is hermetically filled, and the portion through which the wire 68 passes is sealed. However,
Since the wire 68 includes a gap between its strands, sealing is incomplete with only the packings 103, 103, and the gas inside the tank may leak out through the gap between the strands. For this reason, a distance piece 104 is provided to pack the packing 103, 103.
The seal part is divided into two parts, and an inert gas is supplied to the location where the distance piece 104 is located to perform an inert gas purge to prevent the gas inside the tank from diffusing and leaking. When this seal is released and the wire 68 is operated, the worm wheel 107 is rotated in the opposite direction, the packing set screw 106 is raised, and the tightening pressure of the packing 103, 103 is made zero. In such a case, the wire 6 by packing 103, 103
8 is loosened and the frictional force between them is significantly reduced, which not only makes it possible to wind up or unwind the wire 68, but even with such operations, the wire 68 and This prevents damage to the packings 103, 103, etc. In addition, since the seal structure is configured as described above, in order to contain liquefied gas, etc., and operate and operate various devices installed inside the tank, it is possible to penetrate the wall from the outside of the tank and enter the inside. It can effectively seal the penetration part of steel cables, electric wires, spiral pipes, and other flexible long objects that are inserted into and removed from the wire as necessary, and does not cause any particular hindrance to the operation of these wires, etc. Not only does it not occur, but it can be used safely for a long time without any special maintenance work.
Since the dissipation of harmful and dangerous gases can be prevented, it is possible to provide a sealing device that can prevent not only pollution but also unexpected accidents and disasters. Note that the configuration of the seal structure is not limited to the embodiments described above; for example, in the first embodiment, in addition to the cylindrical shape as described above, the movable seal member may be wedge-shaped or semi-conical. Trapezoidal ones can also be used, and in addition to the screw type described above, hydraulic rams, toggle devices, cam mechanisms, etc. can also be used as moving devices. In the second embodiment, For example, the packing can be tightened in the radial direction using a sliding member as shown in the first embodiment, and in either case, the shape of the seal member, its tightening device, and the seal The design of the control device, its driving mechanism, and other components can be changed by applying widely known ones within the range of achieving the above sealing function, and inert gas can also be used for gases targeted for sealing. On the other hand, any inert gas is sufficient, so in some cases air etc. may also be used.
Furthermore, it goes without saying that the location, purpose, etc. of use are not limited to the above.

As described above, in the present invention, the sensor is housed in the detection probe, suspended using a signal cable, and the cable is let out or wound up as necessary by the cable winding device. Various detections and measurements are performed by moving the probe up and down to a desired position inside the tank, but in known cable winding devices, the drum and the cable wound around the drum are integrated into one body. In order to prevent the cable from being twisted by the rotation of the drum, the cable is passed through the shaft of a hollow rotating shaft that rotates together with the signal cable winding drum, concentrically with the hollow rotating shaft, and insulated from each other. A signal extraction device is provided, which is composed of a plurality of conductive sliding members arranged in the same direction, and a conductive slider facing each of the conductive sliding members, and a signal is transmitted through the signal extraction device. I'm doing it.

However, in the signal extraction device as described above, since the sliding member and the slider transmit current through contacts that slide against each other, contact resistance occurs at the contact portion. On the other hand, the signal from the sensor built into the detection probe is often weak, and in some cases can be as weak as the noise caused by this contact resistance, resulting in a poor S/N ratio and making accurate measurement difficult. Ta.

FIG. 7 is a diagram for explaining an example of a cable winding device that reduces the influence of the contact resistance of the signal extraction device as described above and reliably transmits the signal from the sensor to the outside. A preamplifier for signal amplification is provided between the cable wound around the winding drum and the signal extraction device, and this amplifies the weak signal from the sensor transmitted by the flexible multicore cable. It was designed to be taken out.

In FIG. 7, 111 is a probe, 112 is a cable, 113 is a drum that winds up the cable 112, 114 is a hollow rotating shaft, 115 is a slider holder, 116 is a slider, and 117 is a ring-shaped slider. a moving member, 118 a sliding member holder, 119 a fixed wall, 120 a preamplifier, and a probe 111;
As mentioned above, it has a built-in sensor. One end of the cable 112 is connected to the probe 111, which is suspended from the probe 111.
Supplies power to the sensor and transmits signals from the sensor. The drum 1113 is rotated by a hollow rotary shaft 114 fixed thereto, and the cable 112 is let out or wound up to move the probe 111 up and down to a desired position. A hollow rotating shaft 114 passes through the drum 113, one end of which is connected to a drive device (not shown), and the other end fixed to a sliding member holder 115. One end of the cable 112 opposite to the one end connected to the probe 111 is drawn into a suitable hole provided in the hollow rotating shaft 114, and the preamplifier 12 is inserted through this hollow part.
Connected to 0. In the illustrated example, the preamplifier 120 is mounted within the hollow rotating shaft 114, but it may also be mounted within the sliding member holder 115. This preamplifier 120 rotates together with the drum 113, amplifies the weak signal from the sensor transmitted by the cable 112, and transmits it to the signal extraction device. The slider 116 is disposed on the slider holder 115 at an appropriate interval, and is connected to the amplifier 1.
20, respectively. The sliding member holder 118 is fixed to a fixed wall 119, and a sliding member 117 formed in an annular shape is arranged concentrically with the hollow rotating shaft 114, facing each slider 116, respectively. , and are arranged insulated from each other. Further, electric wires are connected to each slider 117, and these wires are collected and guided to the outside. The slider 116 and the sliding member 117 are in contact with each other in a one-to-one correspondence, and the slider 116 is pressed against the sliding member 117 by its elastic force. A signal from a sensor built into the probe 111 is transmitted by a cable 112 to a preamplifier 120, where the signal is amplified and transmitted to a signal extraction device. When the drum 113 is rotated as required, the slider 116 is moved from the slider holder 11.
5 rotates together with the hollow rotating shaft 114,
The slider 116 and the sliding member 117 always maintain one-to-one contact with each other, and the signal is transmitted to the sliding member 117.
is transmitted to. Here, the slider 116 and the sliding member 117 of the signal extraction device slide against each other to transmit current.

FIG. 8 is an explanatory diagram showing another embodiment, in which:
111 to 114 indicate the same components as shown in FIG. 7, 115' is a slider holder, 116' is a slider, 117' is a sliding member, 118' is a sliding member holder, and 119' is a fixed wall, and 120' is a preamplifier. The sliding member holder 118' has a cylindrical shape,
It is fixed to one end of the hollow rotating shaft 114. The sliding members 117' are arranged parallel to each other at appropriate distances in the axial direction on the side surface of the sliding member holder 118', corresponding to the electric wires of the flexible multicore cable 112, and Each is connected to each wire from amplifier 120'. The slider 116' is a thin plate-shaped conductor piece having appropriate elasticity, and the slider holder 1 is placed opposite each of the sliders 117'.
15', and electric wires are connected to each slider 116', and these are gathered and guided to the outside. The slider 116' and the sliding member 117' contact each other in a one-to-one correspondence, and the slider 116' is pressed against the sliding member 117' by its elastic force. The signal from the sensor built into the probe 111 is sent to a preamplifier 120' via a cable 112.
This signal is amplified and transmitted to a signal extraction device. When the drum 113 is rotated as required, the sliding member 117' rotates together with the hollow rotating shaft 114 together with the sliding member holder 118', but the slider 116 and the sliding member 11
7' always maintain one-on-one contact with each other,
The signal is transmitted to slider 116'.

As mentioned above, the sensor used for the detector or measuring device is connected to one end of the signal cable wound around the winding drum, etc., and is suspended inside the tank. The cable is configured to be moved up and down to a desired position inside the tank by rotating the cable supply device to let out and collect the cable. However, in conventionally known devices, the length of the cable or the position of the probe is detected by an encoder or the like that detects the rotation angle of the cable supply device. When the sensor expands or contracts significantly, there is a problem in that a large error may occur in the measured value of the detection probe position.

FIG. 9 is a configuration diagram for explaining an example of a case where the position of the probe can be accurately grasped at all times. Basically, the rotation angle of the cable winding drum or other cable supply device or the cable An encoder that detects the length of the cable, a memory that stores the output of the encoder and the temperature detected by the corresponding temperature sensor, and a correction calculation for the amount of thermal expansion and contraction according to the temperature of each part of the cable. A correction calculation device is provided to calculate an accurate numerical value of the cable length or probe position that has been lost, so that the position of the probe can be displayed accurately at all times.

In FIG. 9, 131 is a storage tank for liquefied gas 132, 133 is a probe equipped with a detector for temperature, density, concentration, etc., 134 is a weight, 135 is a highly flexible multicore signal cable, and 136 137 is a cable supply drum, 137 is an electric signal transmission device such as a slip ring connected to one end of the signal cable 135, 138 is a guide pulley, 139 is a measuring roller, 140 is an encoder, 141 is a sealing device, 142 is a memory, 143 144 is a correction calculation circuit, and 144 is a main data recording device.
The signal cable 135 is connected to the cable supply drum 136
probe 133 and weight 1.
34 is suspended at the highest position near the ceiling of the liquefied gas tank 131 above the surface of the liquefied gas 132. Therefore, when performing measurement, the probe 133
In addition to supplying the necessary power to various detectors within the
The cable supply drum 136 is rotated by a drive device (not shown), the signal cable 135 is fed out, and the probe 133 and the weight 134 are lowered. In such a case, each of the various measuring instruments operates and transmits the measured values to the storage tank 1 via the signal cable 135 and the electrical signal transmission device 137.
31 to the outside. On the other hand, the signal cable 13
5 is fed out length L is measuring roller 1
39 rotation angles, the rotation angles are encoded by encoder 140 and sent to memory 142. All the measured values sent via the electrical signal transmission device 137 are sent to the main data recording device 144 and recorded therein, but only the temperature data T among them is also sent to the memory 142, and the measured values are recorded in the main data recording device 144. It is recorded together with L. Therefore, this L
The relationship between and T is as shown in FIG. 10, for example. Here, To is the temperature inside the measuring chamber where the upper measuring roller 139 of the liquefied gas tank 131 is placed, and as it enters the liquefied gas tank 131 and descends downward, the temperature T decreases significantly. Therefore, a non-negligible error occurs between the position of the probe 133 corresponding to the indicated value of the encoder 140 and the actual position of the probe 133. For this reason, the measured data of T and L is temporarily recorded in the memory 142, and the correction calculation circuit 143 calculates =∫ ^L _p [1-〓(To-T)]dL, and this value is applied to the measuring roller. 1
39 and the encoder 140 is replaced with the true cable length, and thereby the accurate position of the detection probe can be determined. However, here, 〓 is the expansion coefficient of the cable 135.

Therefore, according to this embodiment, since the position of the detection probe can always be accurately known, the distribution state of temperature and other physical quantities can be accurately measured at all times.

As mentioned above, in the present invention, the distribution state of temperature and other physical quantities in the tank is measured by moving the probe up and down, and the measurement operation is performed by a controller controlled by commands from the main computer. It will be done. There are two types of commands from the main computer: measurement and measurement interruption. The measurement command includes the starting position of the measurement by the probe, the measurement interval on the vertical line, and the number of measurements. Note that the information on the liquid level position is sent to the main computer as a measurement value measured by a liquid level gauge provided elsewhere. Further, the liquid level position information is periodically transmitted from the main computer to the controller.

Upon receiving a command from the main computer, a second detector detects the reference position of the probe obtained by a signal from the first transmitter indicating that the probe has landed on the floor. It is compared to see if it matches the position memory, and if it does not match, the position memory, which is the second detection signal, is updated based on the first transmission signal. This is because the signals from the first transmitter indicate the absolute value of the reference position at the bottom of the tank, while the second transmitter is placed at the top of the tank to detect the exact position. This is because, due to changes in the liquid level, liquid temperature, etc. in the tank liquid, the reference position band provided by the first transmitter may not match the reference position where the signal cable is the longest. The probe position is updated as described above, and the probe sequentially measures the temperature, density, etc. at a predetermined position at predetermined intervals. The measurement of these physical quantities is determined to be performed after a period of time necessary for these physical quantities to stabilize, for example, after one minute. If there are multiple tanks, the measured value is transmitted to the main computer along with the tank number and measurement position, and after the transmission is completed, the probe is rolled up to the next measurement position and the same operation is performed. When the measurement is completed for the instructed measurement point, measurement completion information indicating that the measurement is completed is transmitted to the main computer. If the probe is raised above the liquid level of the tank, there is a risk that air bubbles may enter the density detection section built into the probe, so the probe is controlled so as not to rise above the liquid level. When the measurement is completed in this way, the probe is lowered again, updates the probe position memory at the reference position, and waits for the next measurement command.

Except for the measurement circuit for physical quantities such as temperature and density detected by the probe, an abnormality will occur if the tension when hoisting the guide cable, signal cable, etc. exceeds the specified range, or if the anchor is not properly planted. The measurement will be automatically stopped.

FIG. 11 is a flowchart showing the above operations, in which part A is a command waiting part, part B is a probe position memory updating part, part C is a moving part that moves the probe to the next measurement position, and part D is a part that moves the probe to the next measurement position. Section is a temperature and density measurement and measurement end judgment section, E section is a mode change section for stopping the measurement, F section is a section for ending the measurement and updating the probe position memory for the next measurement, and G section is for changing the probe position. This is a setting section for setting the reference position.

Although one embodiment of the present invention has been described above,
The present invention is not limited to the above embodiments,
Various improvements are possible as described below.

FIG. 12 is a diagram showing an example of the twist prevention mechanism of the probe 20 shown in FIG. The probe 20 is a probe support drive cable (signal cable) having a conductive function for transmission, and the probe 20 has two
Although the probe 20 is guided by the two probe guide and support cables 5, 5 and raised and lowered by the signal cable 22, there is a risk that the probe 20 may be twisted due to twisting of the signal cable 22 or the like. 1st
The example shown in FIG. 2 is designed to effectively prevent this twisting, and as shown in the figure, at least two annular plates 151 and 152 are provided on the outer peripheral surface of the probe at a predetermined interval. These two annular plates 1
A guide cable holder 160 is provided between 51 and 152, which is rotatably slidable around the probe 20 and has a hole 160' through which the probe guide support cable 5 passes. In this way, the probe 20 can rotate freely, so even if the probe guide support cable, signal cable, etc. are twisted, the probe 20 will not be twisted thereby.

FIG. 13 is a diagram showing an example of the tank protection mechanism when the plow guide support cable 5 shown in FIG. 1 is cut. In the example shown in FIG. 1, one probe guide support cable 5 is stretched in parallel via the pulley 4, but in this case,
If the probe guide support cable 5 were cut, there was a risk that the pulley 4 would fall to the bottom of the tank 6 and damage the tank. The example shown in FIG. 13 is intended to protect the tank in the event of such a breakage of the probe guide support cable, and as shown in the figure, the probe guide support cable is connected to two cables 5a,
5b, and the end of each cable is connected to a pulley 4.
In this way, even if one of the cables is cut, the pulley 4 will not fall to the bottom of the tank, and the tank can be prevented from being damaged by such a fall of the pulley. In addition,
At this time, it is preferable that the guide cables 5a and 5b are brought into contact with the pulley reel near its diameter, respectively, and then wound around the pulley reel at a required number of rotations so as to be symmetrically fixed to each other.

In addition, when detecting the tension of the signal cable, the net weight of the probe is calculated by subtracting a signal corresponding to the amount of movement of the signal cable from the tension detection signal, and the landing of the probe is detected from the change in the net weight of the probe. Furthermore, for the magnitude of the signal corresponding to the net weight of the probe that detects that the probe has landed, the actual detected signal level is set to a value slightly larger than the noise level added to the probe. It is also possible to prevent error differences due to noise by adding .

Furthermore, the position of the probe in the section from the fixed point on the bottom of the tank to the liquid level above the vertical line of the fixed point is determined by a relational expression between the signal cable tension and the probe position given in advance based on a signal from a detector that detects the tension of the signal cable. or by installing a safety mechanism to stop the prime mover when the tension in the signal cable or guide cable exceeds a predetermined value, or by installing a torque limiter to prevent further tension from being applied. It is also possible to do this.

Furthermore, the relationship between the signal indicating that the probe has landed on the floor and the signal that detects the movement of the probe is set in advance, a predetermined range is defined for the set value, and the landing signal and the movement signal are set in advance. It is also possible to stop the vertical movement when the signal cable exceeds the above range, or to correct the signal indicating the amount of movement of the signal cable using the probe landing signal.

Effects As is clear from the above explanation, according to the present invention, various physical quantities in an LNG tank or the like can be detected safely and accurately.

[Brief explanation of drawings]

Fig. 1 is a side view of the main part for explaining an embodiment of the present invention, Fig. 2 is a plan view of the main part, Fig. 3 is a side view of the weight part, and Fig. 4 is a seal. 5 is a sectional view taken along the line V-V in FIG. 4, FIG. 6 is a sectional view showing another example of the seal portion, and FIGS. 7 and 8 are respectively sectional views of the signal transmission portion. FIG. 9 is a diagram showing an embodiment of the temperature correction measurement device; FIG. 10 is a diagram showing the relationship between the length of the cable and the temperature; FIG. A flowchart for explaining the operation of the measuring device according to the invention, FIG. 12 is a diagram showing an example of a probe twist prevention mechanism, and FIG. 13 is a diagram showing an example of a tank protection mechanism when a cable is broken. 1... Weight, 4... Pulley, 5... Probe guide support cable, 6... Tank, 8... Operation housing,
20... Probe, 22... Probe support drive cable, 66, 70... Inert gas supply pipe, 80
...Seal device, 120, 120'...Preamplifier.

Claims (1)

[Scope of Claims] 1. A probe for detecting physical quantities such as temperature and density of the stored liquid on a vertical line at a fixed point at the bottom of the tank, a signal cable connected to the probe and transmitting the physical signal, and a signal cable disposed outside the tank. , a first lifting device that lifts and lowers the probe via the signal cable; a first sealing mechanism that seals between the inside and outside of the tank of the signal cable; and a first sealing mechanism that detects the tension of the signal cable and changes in the tension. A first transmitter that sends a message that the probe has landed on the ground, a second transmitter that detects the movement of the probe, and two transmitters that guide the probe as it ascends and descends so that the anchor is always applied with equal tension. a second lifting device disposed outside the tank and raising and lowering the anchor via the guide cable; a second sealing mechanism sealing between the inside and outside of the tank of the guide cable; The third part detects the tension of the cable and transmits that the anchor has landed based on the change in tension.
a transmitter and a twist prevention device installed between the guide cable and the signal cable;
An in-tank physical quantity measuring device characterized by measuring a physical quantity in a tank by controlling an elevating device of the tank. 2. A sealing mechanism for sealing between the inside of the tank and the outside of the tank is provided with a mounting base that penetrates the wall surface of the tank and is fixed to the tank wall and through which a cable is inserted, and a mounting base that is attached to the top surface of the mounting base and surrounds or clamps the cable, A pair of seal control devices that drive a seal member formed perpendicularly to the main axis of the cable to release the seal from the cable at any time, and a sealed space formed between the seal members of the pair of seal control devices, The in-tank physical quantity measuring device according to claim 1, further comprising an explosion-proof device for supplying an inert gas into the space. 3. The landing of the probe is determined by the weight of the probe obtained by subtracting the tension corresponding to the length of the signal cable from the tension acting on the signal cable corresponding to the weight of the probe and the signal cable. The in-tank physical quantity measuring device according to claim 1 or 2, wherein the device detects a corresponding net tension. 4. The signal transmission means for transmitting the signal of the ascending and descending probe to the fixed output terminal is connected to an amplifier fixed to the signal cable winding drum and having the signal cable as an input terminal, and between the amplifier output terminal and the fixed output terminal. The in-tank physical measuring device according to any one of claims 1 to 3, characterized in that it comprises a signal cable winding drum and a rotating slip ring for measuring the signal cable. 5 The position of the probe in the section from the fixed point on the bottom of the tank to the liquid level above the vertical line of the fixed point, obtained based on the signal from the first transmitter, is determined from the relational expression between the signal cable tension given in advance and the probe position. The in-tank physical quantity measuring device according to any one of claims 1 to 5, characterized in that the in-tank physical quantity measuring device performs calculation. 6. A patent claim characterized in that the detection signal from the second detector of the signal cable at the time of probe landing is corrected by a signal indicating that the probe has landed from the first detector. The in-tank physical quantity measuring device according to any one of the ranges 1 to 5. 7. Claim 1, characterized in that the first lifting device for lifting and lowering the probe is stopped when the probe reaches a predetermined position with respect to the liquid level.
The in-tank physical quantity measuring device according to any one of Items 7 to 6. 8. The position signal of the probe is corrected by determining the amount of change in the length of the signal cable from the liquid surface to the probe in relation to the liquid temperature. The in-tank physical quantity measuring device according to any one of Item 7. 9. In the second lifting device having two guide cables with equal tension that guide the raising and lowering of the probe, the tension is applied to two guide cables coaxially driven to rotate.
The ends of two guide cables are fixed to each cylindrical surface of the lifting drum, and the other ends of the guide cables are brought into contact with the diameters of the pulley reels, respectively, and then wound around the pulley reel for the necessary rotations, so that each guide cable is symmetrically wound. 2. The in-tank physical quantity measuring device according to claim 1, wherein the in-tank physical quantity measuring device is fixed to the pulley shaft and is obtained by suspending an anchor from the pulley shaft. 10 The anchor has a cylindrical upper and lower double structure,
The lower anchor has a plurality of guide rods implanted parallel to and symmetrical to the axis of the cylindrical body, and the upper anchor has a through hole drilled through the axis symmetrically so that it can slide within a predetermined range using the guide rods as a guide. The in-tank physical quantity measuring device according to any one of claims 1 to 9, characterized in that the device is connected to a tank. 11 The torsion prevention device installed between the guide cable and the signal cable consists of two plates fixed at a predetermined interval to the outer periphery of the guide cable and the probe located approximately in the center of the guide cable. The present invention is characterized in that at least one set of guide cable holders is provided between the annular plates, the guide cable holder is rotatably slidable around the probe between the annular plates, and has a through hole that passes through the guide cable. The in-tank physical quantity measuring device according to any one of the ranges 1 to 10.