Hydraulic control device for forced opening gate

Abstract

To smoothly open a door by minimizing resistance when the door is opened in a hydraulic control device of a forced opening type gate, and to suppress fluttering of the door due to waves when the door is closed by its own weight.SOLUTION: A hydraulic control device comprises a double rod hydraulic cylinder 3 having a front oil port 3a, a rear oil port 3b, a rod 8 and the like, a door body 1 that opens and closes in conjunction with movement of the rod 8, a first communication pipe 10 having a check valve 11 and connecting the front oil port 3a and the rear oil port 3b, a second communicating pipe 12 connecting the front side and the rear side of the check valve 11 and having a float valve 4b and a flow control valve 13, a hydraulic pump 17 for supplying hydraulic oil, a hydraulic oil supply pipe 14 having a supply check valve 15a and an oil pressure detection device 22, a hydraulic oil discharge pipe 16 having a discharge piloted check valve 15b, and a hydraulic pump control device 23 for operating and stopping the hydraulic pump 17 based on a water level detection device 21 and the water level signal from the water level detection device 21 and the oil pressure signal from the oil pressure detection device 22.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a hydraulic control device for appropriately controlling the opening and closing of a forced-open gate that is installed at the outlet of a sluice gate or a flowing water channel for the purpose of preventing backflow. [Background technology]

[0002] Conventionally, flap gates or the like are installed at the outlet of a general culvert or flow channel in order to prevent backflow from the downstream side. However, conventional flap gates have problems such as poor drainage performance because the water passage is normally closed, and debris can easily get caught, resulting in incomplete closure. In addition, when the downstream water level fluctuates drastically due to waves or the like, the gate body repeatedly opens and closes vigorously in sync with the water level fluctuations, causing repeated violent collisions between the gate body and the door stopper for a long period of time, resulting in noise and damage.

[0003] Therefore, the applicant has developed a hydraulic control device for a forced-open gate, as described in Patent Document 1 (JP 2019-112860 A, in particular paragraphs 0020-0021 and Figures 4 and 5), in which the gate body is normally kept in the open position to achieve high drainage performance, and when the water level downstream reaches or exceeds a predetermined level, the float valve switches to the closed position, causing the gate body to close under its own weight, thereby reliably stopping the water. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-112860 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the hydraulic control device of the forced-open type gate described in Patent Document 1, when the gate body is opened and closed automatically (the state in Figures 5 and 6), the movement speed of the hydraulic oil is set by the flow control valve (11), and the opening and closing speed of the gate body is always below a predetermined speed. Therefore, there is a problem that the gate body does not open quickly, especially when it is opened only by the water pressure of the drainage flow from the upstream side (the state in Figure 6). In addition, when the scale of the facility is large, the weight of the gate body becomes heavy and a relatively large opening force is required, which causes the problem that the gate cannot be opened reliably with a small amount of drainage water. When the amount of drainage water from the upstream side is small, the upstream water level rises gradually as the water accumulates in the waterway upstream of the closed gate body, and the gate body opens slightly due to the water pressure of the increased water level, but because a constant level of accumulated water (dead water) occurs upstream of the gate body, it is easy for soil, vegetation, and rubbish to accumulate. Furthermore, when forcibly opening the flap gate, in order to change from the state shown in Figure 6 to the state shown in Figure 7, it was necessary to close the first stop valve (12) and open the second stop valve (13). After the forced opening operation was completed, the reverse operations had to be carried out, which created a problem in that it was a heavy burden to carry out management operations every time the river water level rose. In particular, in the case of flap gate facilities on the coast, the automatic closing operation occurs twice a day due to the rising tide level at high tide, so in facilities where the amount of water discharged from the upstream is small, it was necessary to carry out management operations to forcibly open the gates every time the tide went out. The present invention has as its first objective the provision of a hydraulic control device which solves these problems and which can smoothly open the gate body with minimal resistance when the gate body is opened due to the water pressure of the drainage flow from the upstream side, and which can suppress flapping of the gate body due to waves by slowing down the closing speed when the downstream water level reaches or exceeds a predetermined level, causing the float valve to switch to the closed position and the gate body to close under its own weight. In addition, a second objective of the present invention is to provide a hydraulic control device that automatically operates the hydraulic pump to forcibly open the gate without any management operation when the downstream water level has dropped sufficiently after the automatic closing operation has been performed and the amount of water drained from the upstream side is small. [Means for solving the problem]

[0006] The invention according to claim 1 is A hydraulic control device for a forced opening type gate that is closed by its own weight, a double-rod hydraulic cylinder (3) having a rod (8) that moves in conjunction with the movement of hydraulic oil, a front oil port (3a) and a rear oil port (3b); a door body (1) that moves in a closing direction when the rod (8) moves to the side where the front oil port (3a) is located, and moves in an opening direction when the rod (8) moves to the side where the rear oil port (3b) is located; a first communication pipe (10) communicating between the front oil port (3a) and the rear oil port (3b); a check valve (11) provided in the first communication pipe (10) and allowing hydraulic oil to flow only in a direction from the rear oil port (3b) to the front oil port (3a); a second communicating pipe (12) communicating between a front side and a rear side of the check valve (11) in the first communicating pipe (10); a float valve (4b) provided in the second communication pipe (12) and opened when a downstream water level (19b) downstream of the forced opening gate reaches or exceeds a predetermined water level, and a flow control valve (13) for adjusting the flow rate of the hydraulic oil so as not to exceed a predetermined flow rate; a hydraulic tank (18) for storing hydraulic oil; a hydraulic pump (17) that supplies hydraulic oil from the hydraulic tank (18) to the double rod type hydraulic cylinder (3); a hydraulic oil supply pipe (14) connecting a hydraulic oil outlet of the hydraulic pump (17) to a side of the first communicating pipe (10) relative to the check valve (11) toward the front oil port (3 a) or connecting the hydraulic oil outlet to a side of the second communicating pipe (12) relative to the float valve (4 b) and the flow rate control valve (13) toward the front oil port (3 a); a supply check valve (15a) provided in the hydraulic oil supply pipe (14); a hydraulic oil discharge pipe (16) connecting the hydraulic tank (18) and a side of the first communicating pipe (10) from the check valve (11) to the rear oil port (3 b) or connecting the hydraulic tank (18) and a side of the second communicating pipe (12) from the float valve (4 b) and the flow rate control valve (13) to the rear oil port (3 b); a check valve (15b) with a discharge pilot provided in the hydraulic oil discharge pipe (16); a water level detection device (21) that detects whether the downstream water level (19b) is equal to or lower than a specific water level; a hydraulic pressure detection device (22) that detects whether or not the supply pipe hydraulic pressure in the hydraulic oil supply pipe (14) is less than a predetermined pressure; a hydraulic pump control device (23) that operates the hydraulic pump (17) when the water level detection device (21) detects that the downstream water level (19b) is equal to or lower than the specific water level and the oil pressure detection device (22) detects that the supply pipe oil pressure is lower than the predetermined pressure, and that stops the hydraulic pump (17) when the water level detection device (21) detects that the downstream water level (19b) is not equal to or lower than the specific water level or the oil pressure detection device (22) detects that the supply pipe oil pressure is not lower than the predetermined pressure, When hydraulic oil is supplied from the hydraulic tank (18) to the double-rod hydraulic cylinder (3) via the hydraulic pump (17), the hydraulic oil supply pipe (14), the supply check valve (15a), the first communicating pipe (10), and the front oil port (3a), hydraulic oil is discharged from the double-rod hydraulic cylinder (3) to the hydraulic tank (18) via the rear oil port (3b), the first communicating pipe (10), the hydraulic oil discharge pipe (16), and the discharge pilot-equipped check valve (15b).

[0007] The invention according to claim 2 is as follows: In the hydraulic control device according to claim 1, the hydraulic pressure detection device (22) is replaced with a door body opening degree detection device (24) that detects whether the opening degree of the door body (1) is less than a predetermined opening degree or not, The hydraulic pump control device (23) is characterized in that it operates the hydraulic pump (17) when the water level detection device (21) detects that the downstream water level (19b) is equal to or lower than the specific water level and when the door body openness detection device (24) detects that the degree of opening of the door body (1) is less than the predetermined degree of opening, and stops the hydraulic pump (17) when the water level detection device (21) detects that the downstream water level (19b) is not equal to or lower than the specific water level or when the door body openness detection device (24) detects that the degree of opening of the door body (1) is not less than the predetermined degree of opening.

[0008] The invention according to claim 3 is the hydraulic control device according to claim 1 or 2, a third communication pipe (25) communicating between the supply check valve (15a) and the hydraulic pump (17) in the hydraulic oil supply pipe (14) and between the discharge pilot-equipped check valve (15b) and the hydraulic tank (18) in the hydraulic oil discharge pipe (16); The hydraulic system further includes a relief valve (26) that is provided in the third communicating pipe (25) and allows hydraulic oil to flow from the hydraulic oil supply pipe (14) to the hydraulic oil discharge pipe (16) when the communicating pipe oil pressure in the third communicating pipe (25) becomes equal to or higher than the predetermined pressure. Effect of the Invention

[0009] According to the invention of claim 1, there are provided a first communicating pipe (10) communicating the front oil port (3a) and the rear oil port (3b) of the double-rod hydraulic cylinder (3), a check valve (11) provided in the first communicating pipe (10) and allowing the hydraulic oil to flow only in the direction from the rear oil port (3b) to the front oil port (3a), a second communicating pipe (12) communicating the front side and the rear side of the check valve (11), a float valve (4b) provided in the second communicating pipe (12) and opening when the water level (19b) downstream of the gate reaches or exceeds a predetermined water level, and a flow control valve (13) adjusting the flow rate of the hydraulic oil so as not to exceed a predetermined flow rate. Therefore, when the float valve (4b) is closed, the hydraulic oil flows without resistance from the rear oil port (3b) to the front oil port (3a), and the gate body (1) is smoothly opened by the water pressure of the drainage flow from the upstream side, etc. At this time, the hydraulic oil does not flow from the front oil port (3a) to the rear oil port (3b), so that once the door body (1) is opened, the open state can be maintained. In addition, when the float valve (4b) is in the open state, hydraulic oil flows from the front oil port (3a) to the rear oil port (3b) via the flow control valve (13), so that the gate body (1) can move in the closing direction under its own weight. However, the action of the flow control valve (13) slows down the operating speed, thereby preventing the gate body (1) from flapping due to waves, etc. The invention according to claim 1 further comprises a hydraulic tank (18), a hydraulic pump (17), a hydraulic oil supply pipe (14), a supply check valve (15a) provided in the hydraulic oil supply pipe (14), a hydraulic oil discharge pipe (16), a discharge pilot-equipped check valve (15b) provided in the hydraulic oil discharge pipe (16), a water level detection device (21) that detects whether the downstream water level (19b) is equal to or lower than a specific water level, a hydraulic pressure detection device (22) that detects whether the supply pipe hydraulic pressure in the hydraulic oil supply pipe (14) is lower than a predetermined pressure, and a hydraulic pump control device ( The hydraulic pump control device (23) operates the hydraulic pump (17) when the water level detection device (21) detects that the downstream water level (19b) is equal to or lower than a specific water level and when the oil pressure detection device (22) detects that the supply pipe oil pressure is less than a predetermined pressure, and stops the hydraulic pump (17) when the water level detection device (21) detects that the downstream water level (19b) is not equal to or lower than the specific water level or when the oil pressure detection device (22) detects that the supply pipe oil pressure is not less than the predetermined pressure. Therefore, when the downstream water level has dropped sufficiently after the gate has been automatically closed and the amount of water drained from the upstream side has decreased, the hydraulic pump can be operated automatically without any management operations, and the hydraulic pump can be stopped at the appropriate time.

[0010] According to the invention of claim 2, in the hydraulic control device of claim 1, the hydraulic pressure detection device (22) is replaced with a door body opening degree detection device (24) that detects whether the opening degree of the door body (1) is less than a predetermined opening degree or not, and the hydraulic pump control device (23) operates the hydraulic pump (17) when the water level detection device (21) detects that the downstream side water level (19b) is equal to or lower than a specific water level and the door body opening degree detection device (24) detects that the opening degree of the door body (1) is less than the predetermined opening degree. The hydraulic pump (17) is stopped when it is detected that the water level is not below the predetermined level, or when the gate body openness detection device (24) detects that the openness of the gate body (1) is not less than a predetermined openness. Therefore, by using a simple device without using a hydraulic detection device (22), as in the invention of claim 1, when the downstream water level (19b) has dropped sufficiently after the automatic closing operation of the gate has been performed and the amount of water drained from the upstream side has decreased, the hydraulic pump (17) can be automatically operated and stopped at an appropriate timing without management operation.

[0011] According to the invention of claim 3, in addition to the effects of the invention of claim 1 or 2, there is further provided a third communicating pipe (25) communicating between the hydraulic oil supply pipe (14) and the hydraulic oil discharge pipe (16), and a relief valve (26) provided in the third communicating pipe (25) for allowing hydraulic oil to flow from the hydraulic oil supply pipe (14) to the hydraulic oil discharge pipe (16) when the communicating pipe oil pressure reaches or exceeds a predetermined pressure. Therefore, when a problem occurs in the hydraulic pressure detection device (22) or the door body opening detection device (24), etc., causing a problem in stopping the hydraulic pump (17), it is possible to prevent the door body (1) from being opened beyond the upper limit. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a perspective view of an upper hinge type flap gate according to a first embodiment. [Diagram 2] FIG. 1 is a diagram showing a configuration of a hydraulic operation device and the like according to a first embodiment. [Diagram 3] FIG. 2 is a diagram showing a state of the hydraulic operation device according to the first embodiment (during automatic opening operation after opening). [Figure 4]FIG. 4 is a diagram for explaining the flow of hydraulic oil in the first embodiment (during automatic closing operation). [Diagram 5] FIG. 2 is a diagram showing a state of the hydraulic operation device according to the first embodiment (when closed). [Figure 6] FIG. 2 is a diagram showing a state of the hydraulic operation device and the like according to the first embodiment (during automatic opening operation after closing). [Figure 7] FIG. 4 is a diagram for explaining the flow of hydraulic oil in the first embodiment (at the start of forced opening). [Figure 8] FIG. 4 is a diagram showing a state of the hydraulic operation device according to the first embodiment (at the end of forced opening). [Figure 9] 5A to 5C are diagrams illustrating the operation of the water level detection device (21). [Figure 10] 4 is a diagram illustrating the relationship between the opening degree of the door body (1) and the supply pipe oil pressure (p). FIG. [Figure 11] FIG. 11 is a diagram showing the configuration of a hydraulic operation device and the like according to a second embodiment. [Figure 12] FIG. 11 is a diagram showing the configuration of a hydraulic operation device and the like according to a third embodiment. [Figure 13] FIG. 13 is a diagram showing the configuration of a hydraulic operation device and the like according to a fourth embodiment. [Figure 14] FIG. 4 is a diagram showing a configuration of a hydraulic operation device and the like according to a modified example of the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, the embodiments of the present invention will be described with reference to examples. EXAMPLES

[0014] FIG. 1 is a perspective view of an upper hinge type flap gate according to a first embodiment. In the upper hinge type flap gate of Example 1, as shown in Figure 1, a gate body 1 is suspended freely rotatably by a hinge hardware 6 at the boundary between the upstream waterway and the downstream waterway, and when no external force is applied, the gate body 1 closes the outlet of the upstream waterway by its own weight. In addition, a door body drive arm 1a is provided on the upper part of the door body 1 and is hingedly connected to a tip metal fitting 9 provided at the tip of the rod 8 of the double-rod hydraulic cylinder 3, so that the opening and closing operation of the door body 1 and the extension and retraction operation of the rod of the double-rod hydraulic cylinder 3 are always synchronized. The double rod hydraulic cylinder 3 is attached to a trunnion bearing 7 so that the rod 8 retracts when the door body 1 opens, and extends when the door body 1 closes. Conversely, when the rod 8 retracts, the door body 1 opens, and when the rod 8 extends, the door body 1 closes. Furthermore, a float 4a, a float valve 4b and a water level detector 21, which will be described later, are housed inside the float device storage box 4c, and a door stopper 5 is provided around the outlet of the upstream waterway.

[0015] FIG. 2 is a diagram showing the configuration of the hydraulic operation device etc. according to the first embodiment. The front oil port 3a and the rear oil port 3b of the double-rod hydraulic cylinder 3 are connected by a first connecting pipe 10, and the first connecting pipe 10 is provided with a check valve 11 that allows hydraulic oil to flow only in the direction from the rear oil port 3b to the front oil port 3a. Furthermore, the double-rod hydraulic cylinder 3 has the characteristic that the amount of hydraulic oil inside the cylinder does not change even when the rod 8 is extended or retracted, so that the hydraulic oil can flow freely between the front oil port 3a and the rear oil port 3b, allowing the rod 8 to be freely extended or retracted by external force. In addition, the front side (the side closer to the front oil port 3a) and the rear side (the side closer to the rear oil port 3b) of the check valve 11 in the first communicating pipe 10 are connected by a second communicating pipe 12, and the second communicating pipe 12 is provided with a float valve 4b that opens when the downstream water level in the water passage 2b downstream of the gate reaches or exceeds a predetermined water level, and a flow control valve 13 that adjusts the flow rate of the hydraulic oil so that it does not exceed a predetermined flow rate. Next, the first communicating pipe 10 is connected to the hydraulic tank 18 on the front side of the check valve 11 by a hydraulic oil supply pipe 14, and the first communicating pipe 10 is connected to the hydraulic tank 18 on the rear side of the check valve 11 by a hydraulic oil discharge pipe 16. The hydraulic oil supply pipe 14 is provided with a hydraulic pump 17 for supplying hydraulic oil from the hydraulic tank 18 to the double-rod hydraulic cylinder 3, a supply check valve 15a, and a hydraulic pressure detection device 22 for detecting whether the hydraulic pressure in the hydraulic oil supply pipe 14 (supply pipe hydraulic pressure) is below a predetermined pressure, and the hydraulic oil discharge pipe 16 is provided with a discharge pilot-equipped check valve 15b for preventing the flow of hydraulic oil from the rear oil port 3b to the hydraulic tank 18 except when the hydraulic oil is supplied from the hydraulic tank 18 by the hydraulic pump 17. Furthermore, the system is equipped with a water level detection device 21 which detects whether the downstream water level is below a specific water level which is lower than a predetermined water level, and outputs a water level signal indicating that it is below the specific water level, a hydraulic pressure detection device 22 which detects whether the supply pipe hydraulic pressure in the hydraulic oil supply pipe 14 is below a predetermined pressure, and outputs a hydraulic pressure signal indicating that it is below the predetermined pressure, and a hydraulic pump control device 23 which operates the hydraulic pump 17 when it receives a water level signal from the water level detection device 21 and a hydraulic pressure signal from the hydraulic pressure detection device 22, and stops the hydraulic pump 17 when it stops receiving either the water level signal or the hydraulic pressure signal.

[0016] FIG. 3 is a diagram showing the state of the hydraulic operating device and the like according to the first embodiment during automatic opening operation after the door body 1 is opened. As shown in Fig. 3, when the downstream water level 19b is lower than a predetermined water level, that is, when the float valve 4b is closed and the second communicating pipe 12 is in a closed state, the hydraulic oil can only move from the rear oil port 3b to the front oil port 3a, so the rod 8 of the double-rod hydraulic cylinder 3 can only contract. Note that the closed state of the float valve 4b and the closed state of the second communicating pipe 12 include a state in which the hydraulic oil cannot move in both directions and a state in which the hydraulic oil is allowed to flow only in the direction from the rear oil port 3b to the front oil port 3a as shown in Fig. 3 (from right to left in Fig. 3). In this state, when the upstream water level 19a in the waterway 2a upstream of the gate rises and the gate body 1 is pushed in the discharge direction by the water pressure from the upstream side, hydraulic oil flows in the first communication pipe 10 from the rear oil port 3b to the front oil port 3a, and the automatic opening operation is performed. Then, even if the upstream water level drops thereafter and the water pressure becomes smaller, the rod 8 cannot extend, so the open state of the gate body 1 is maintained. Also, the hydraulic pump 17 does not operate in the state shown in FIG. 3.

[0017] FIG. 4 is a diagram for explaining the flow of hydraulic oil in the first embodiment during an automatic closing operation, and FIG. 5 is a diagram showing the state of the hydraulic operating device and the like according to the first embodiment when the door body 1 is closed. 3, when the downstream water level 19b rises and the float 4a rises to open the float valve 4b, hydraulic oil can move from the front oil port 3a to the rear oil port 3b via the first communicating tube 10, the second communicating tube 12, the float valve 4b, the flow control valve 13, and the first communicating tube 10, so that the rod 8 of the double-rod hydraulic cylinder 3 can not only contract but also extend. Therefore, in this state, the door body 1 can perform automatic opening and closing operations in response to fluctuations in the upstream water level 19a and the downstream water level 19b. In other words, when the upstream water level 19a is higher than the downstream water level 19b and the water pressure in the drainage direction of the upstream water level 19a is greater than the water pressure due to the downstream water level 19b and the pressure due to the weight of the gate body 1, the automatic opening operation is performed and water is drained from the upstream side of the gate in the downstream direction. Conversely, when the upstream water level 19a is lower than or equal to the downstream water level 19b and the water pressure in the discharge direction of the upstream water level 19a is smaller than the water pressure due to the downstream water level 19b and the pressure due to the weight of the door body 1, as shown in Figure 4, the door body 1 will attempt to rotate in the closing direction due to the water pressure due to the downstream water level 19b and the weight of the door body 1, and the rod 8 will attempt to move in the direction of the black arrow. Then, the hydraulic oil flows through the first communicating pipe 10 and the second communicating pipe 12 in the direction from the front oil port 3a to the rear oil port 3b, as shown by the white arrows, so that the door body 1 moves in the closing direction and an automatic closing operation is performed, finally reaching the state shown in Figure 5. At this time, the flow rate of the hydraulic oil flowing through the second communicating pipe 12 does not exceed a predetermined flow rate due to the action of the flow control valve 13, so the extension speed of the rod 8 is limited and the automatic closing speed of the door body 1 is slow. Therefore, it is possible to prevent the door body 1 from closing at high speed and causing a violent collision with the door stop 5, and it is possible to prevent noise and damage.

[0018] FIG. 6 is a diagram showing the state of the hydraulic operating device etc. of Example 1 during automatic opening operation after the door body 1 is closed, FIG. 7 is a diagram explaining the flow of hydraulic oil in Example 1 at the start of forced opening, and FIG. 8 is a diagram showing the state of the hydraulic operating device etc. of Example 1 at the end of forced opening. Even if the downstream water level 19b drops from the gate closed state during automatic closing operation shown in Figure 5, the float valve 4b closes and the gate becomes capable of automatic opening, the gate will remain closed if the water level difference between the upstream water level 19a and the downstream water level 19b is small as shown in Figure 6 and the water pressure from the upstream side is smaller than the pressure due to the weight of the gate body 1. In particular, if the upstream water level 19a is quite low when the automatic closing operation is performed, the gate will remain closed even if the downstream water level 19b drops as shown in Figure 7, and even if the water pressure from the upstream side becomes greater than the pressure due to the weight of the gate body 1, it will only open slightly according to the amount of water discharged, which creates the problem that vegetation, soil, or debris is likely to accumulate upstream of the gate. Therefore, in this embodiment, the hydraulic pump 17 is operated when the downstream water level 19b is equal to or lower than a specific water level and the opening angle of the gate body 1 is less than a predetermined angle. When the hydraulic pump 17 is operated, as shown by the white arrow in FIG. 7, the hydraulic oil flows into the front oil chamber of the double-rod hydraulic cylinder 3 via the hydraulic oil supply pipe 14, supply check valve 15a, hydraulic oil supply pipe 14, first connecting pipe 10, and front oil port 3a, and accordingly the hydraulic oil in the rear oil chamber is discharged to the hydraulic tank 18 via the rear oil port 3b, first connecting pipe 10, hydraulic oil discharge pipe 16, discharge pilot-equipped check valve 15b, and hydraulic oil discharge pipe 16. As a result, the rod 8 moves in the direction of the black arrow in FIG. 7 and the door body 1 rotates in the opening direction. Thereafter, when the opening angle of the gate body 1 reaches a predetermined angle, the hydraulic pump 17 is stopped, resulting in the state shown in Figure 8. However, the hydraulic pump 17 is also stopped if the downstream water level 19b rises to or exceeds a specific water level before the state shown in Figure 8 is reached. After the state shown in FIG. 8 is reached, the upstream water level 19a and the downstream water level 19b become the same height, and the drainage water from the upstream side flows smoothly to the downstream side.

[0019] FIG. 9 is a diagram illustrating the operation of the water level detection device 21. The water level detection device 21 of the first embodiment is composed of a detection electrode 21a, an earth electrode 21b, an electric wire 21c electrically connected to the detection electrode 21a, and an electric wire 21d electrically connected to the earth electrode 21b. The lower ends of the detection electrode 21a and the earth electrode 21b are disposed at the height of a specific water level, and an AC voltage is applied between the earth electrode and the detection electrode. When the downstream water level 19b is higher than the specific water level as shown in Figure 9(A), the detection electrode 21a and the earth electrode 21b are both submerged, so that current flows between the two electrodes, and when the downstream water level 19b is below the specific water level as shown in Figure 9(B), the two electrodes are no longer in contact with the water, so that no current flows between the two electrodes. By detecting the value of the current flowing between these two electrodes, the output of a water level signal indicating that the downstream water level 19b is below a specific water level is controlled. The specific water level should be lower than the specified water level at which the float valve 4b opens and higher than the minimum water level of the downstream water level 19b, but it is usually set to a position slightly higher than the steady water level or average water level of the downstream water level 19b when the gate body 1 is fully open.

[0020] FIG. 10 is a diagram for explaining the relationship between the opening degree of the door body 1 and the supply pipe oil pressure p (MPa). The degree of opening of the door body 1 is represented by the angle θ (°) shown in Fig. 10(A). In other words, θ is a value indicating how many degrees the door body 1 has rotated from the fully closed state. FIG. 10(B) is a graph showing the relationship between the opening degree θ of the door body 1 and the supply pipe oil pressure p (the operating pressure during forced opening or the holding pressure during automatic opening operation). As can be seen from the graph in Figure 10(B), as θ increases, p also increases monotonically, so if the value of the supply pipe oil pressure pa for an arbitrary opening degree θa is measured and stored in advance for each gate equipment, the opening degree θ of the gate body 1 can be determined by detecting the supply pipe oil pressure p. Therefore, by detecting whether the supply pipe oil pressure in the hydraulic oil supply pipe 14 is below a predetermined pressure with the hydraulic pressure detection device 22, it is possible to detect whether the opening degree of the gate body 1 is below a predetermined angle. Therefore, if the predetermined angle corresponding to the predetermined pressure is set to approximately 90% or less of the maximum opening angle of the gate body 1, when the downstream water level 19b is low and the opening degree of the gate body 1 is insufficient, the hydraulic pump 17 can be reliably operated to forcibly open the gate body 1, and the hydraulic pump 17 can be stopped before the gate body 1 reaches a fully open state, thereby smoothly maintaining the open state of the gate body 1. In order to avoid a state in which the opening degree of the gate body 1 is small and to prevent floating vegetation, soil, or rubbish from accumulating on the upstream side of the gate, it is sufficient to set the specified angle to 30% or more of the maximum opening angle, but it is better to set it to 40% or more, taking into account a decrease in the opening degree. EXAMPLES

[0021] FIG. 11 is a diagram showing the configuration of a hydraulic operation device etc. according to the second embodiment. The hydraulic operating device of Example 2 and the hydraulic operating device of Example 1 (Figure 2) have exactly the same configuration except that a door body openness detection device 24 is added to a part of the door body drive arm 1a, the installation position of the hydraulic detection device 22 is changed to between the supply check valve 15a and the hydraulic pump 17, and the control conditions of the hydraulic pump control device 23 are changed. Therefore, the same members as those in the first embodiment are given the same reference numbers, and the following mainly describes the differences from the first embodiment.

[0022] The door body openness detection device 24 added in the second embodiment is an angle sensor that measures the angle between the longitudinal direction of the door body drive arm 1a and a horizontal or vertical plane. Since the angle measured by the door body openness detection device 24 has a one-to-one correspondence with the openness of the door body 1, the door body openness detection device 24 detects whether the openness of the door body 1 is less than a predetermined angle based on the measured angle, and outputs an angle signal indicating that it is less than the predetermined angle. Next, the oil pressure detection device 22 of the second embodiment has the same function as the previous embodiment, namely, detecting whether the supply pipe oil pressure in the hydraulic oil supply pipe 14 is below a predetermined pressure and outputting an oil pressure signal indicating that the supply pipe oil pressure is below the predetermined pressure, although the installation position is different. In addition, the hydraulic pump control device 23 of Example 2 operates the hydraulic pump 17 when it receives a water level signal from the water level detection device 21 and an angle signal from the door body openness detection device 24, and stops the hydraulic pump 17 when it stops receiving either the water level signal or the hydraulic signal from the hydraulic pressure detection device 22. EXAMPLES

[0023] FIG. 12 is a diagram showing the configuration of a hydraulic operation device etc. according to the third embodiment. The hydraulic operating device of Example 3 and the hydraulic operating device of Example 1 (Figure 2) have exactly the same configuration except that a door body openness detection device 24 has been added to a part of the door body drive arm 1a (the same as in Example 2), the hydraulic detection device 22 is not installed, and the control conditions of the hydraulic pump control device 23 have been changed. Therefore, the same members as those in the first and second embodiments are designated by the same reference numbers, and the following description will focus mainly on the differences from the first and second embodiments.

[0024] The door body openness detection device 24 of the third embodiment has the same structure and function as that of the second embodiment. The hydraulic pump control device 23 of the third embodiment operates the hydraulic pump 17 when it receives a water level signal from the water level detection device 21 and an angle signal from the door body openness detection device 24, and stops the hydraulic pump 17 when it stops receiving either the water level signal or the angle signal. Therefore, it is possible to provide a hydraulic operation device which is simpler in structure than the first and second embodiments and is less expensive. EXAMPLES

[0025] FIG. 13 is a diagram showing the configuration of a hydraulic operation device etc. according to the fourth embodiment. The hydraulic operating device of Example 4 and the hydraulic operating device of Example 1 (Figure 2) have exactly the same configuration except for the addition of a third communicating pipe 25 that connects between the supply check valve 15a in the hydraulic oil supply pipe 14 and the hydraulic pump 17, and between the discharge pilot-equipped check valve 15b in the hydraulic oil discharge pipe 16 and the hydraulic tank 18, and the provision of a relief valve 26 in the third communicating pipe 25. Therefore, the same members as those in the first embodiment are given the same reference numbers, and the following mainly describes the differences from the first embodiment.

[0026] The relief valve 26 of the fourth embodiment allows hydraulic oil to flow from the hydraulic oil supply pipe 14 to the hydraulic oil discharge pipe 16 when the hydraulic pressure (communicating pipe hydraulic pressure) in the third communicating pipe 25 reaches or exceeds a predetermined pressure, and therefore discharges hydraulic oil from the hydraulic oil discharge pipe 16 to the hydraulic tank 18 when the supply pipe hydraulic pressure p in the hydraulic oil supply pipe 14 rises too high due to a failure of the elements (water level detection device 21 and hydraulic pressure detection device 22) that control the hydraulic pump control device 23, etc. The action of this relief valve 26 makes it possible to prevent the door body 1 from opening beyond the fully open state.

[0027] Modifications of Examples 1 to 4 are listed below. (1) In the first to fourth embodiments, the flow control valve 13 is provided on the rear oil port 3b side of the float valve 4b of the second communicating pipe 12. However, the flow control valve 13 may be provided on the front oil port 3a side of the float valve 4b of the second communicating pipe 12. (2) In Examples 1 to 4, an upper hinged flap gate was used, but in all of the examples, any gate, such as a miter gate, may be used as long as it is a gate that closes under its own weight and moves in the opening or closing direction depending on the water pressure of the upstream or downstream water level. (3) In the water level detection device 21 in Examples 1 to 4, the lower ends of the detection electrode 21a and the earth electrode 21b are positioned at the height of the specific water level, but it is also possible to use a depth gauge and output a water level signal when the measured water depth falls below the depth corresponding to the specific water level.

[0028] (4) In the first to fourth embodiments, the hydraulic oil supply pipe 14 connects the hydraulic oil outlet of the hydraulic pump 17 to the forward oil port 3a side of the check valve 11 of the first communicating pipe 10. However, as shown in FIG. 14 (an example of a modified configuration of the hydraulic operating device etc. according to the first embodiment), the hydraulic oil supply pipe 14 may connect the hydraulic oil outlet of the hydraulic pump 17 to the forward oil port 3a side of the float valve 4b of the second communicating pipe 12. In addition, the hydraulic oil discharge pipe 16 connects the hydraulic tank 18 to the rear oil port 3b side of the check valve 11 of the first communicating pipe 10, but as shown in Figure 14, it may also connect the hydraulic tank 18 to the rear oil port 3b side of the flow control valve 13 of the second communicating pipe 12. Furthermore, the hydraulic oil supply pipe 14 may be connected as shown in FIG. 2 and the hydraulic oil discharge pipe 16 may be connected as shown in FIG. 14, or conversely, the hydraulic oil supply pipe 14 may be connected as shown in FIG. 14 and the hydraulic oil discharge pipe 16 may be connected as shown in FIG. 2.

[0029] (5) The hydraulic pump control device 23 in Example 2 operates the hydraulic pump 17 when it receives a water level signal from the water level detection device 21 and an angle signal from the door body openness detection device 24, and stops the hydraulic pump 17 when it stops receiving either the water level signal or the hydraulic signal from the hydraulic pressure detection device 22. However, the hydraulic pump 17 may be operated when it receives a water level signal and an angle signal or a water level signal and a hydraulic pressure signal, and the hydraulic pump 17 may be stopped when it stops receiving any of the water level signal, hydraulic pressure signal, and angle signal. In this case, the hydraulic pump 17 can be operated or stopped more reliably. (6) In the modified example of (5) above, the hydraulic pump 17 is operated when a water level signal and an angle signal or a water level signal and an oil pressure signal are received, but the hydraulic pump 17 may be operated when a water level signal and an oil pressure signal are received.

[0030] (7) In the first to fourth embodiments and the modified examples of (5) and (6) above, the hydraulic pump 17 is operated under various conditions and then stopped. However, instead of or in addition to these conditions, a timer may be provided in the hydraulic pump control device 23, and the hydraulic pump 17 may be stopped when a time set on the timer has elapsed since the hydraulic pump 17 was operated. By doing so, the risk of the hydraulic pump 17 operating excessively can be reduced. (8) The door body openness detection device 24 in the second and third embodiments and the above modified examples (5) and (6) measures the angle between the longitudinal direction of the door body drive arm 1a and the horizontal or vertical plane, but may measure the length of the rod 8 protruding forward or backward of the double-rod hydraulic cylinder 3. In such a case, since the length measured by the door body openness detection device corresponds one-to-one to the openness of the door body 1, the door body openness detection device detects whether the openness of the door body 1 is less than a predetermined angle based on the measured length and outputs an angle signal indicating that the openness is less than the predetermined angle. (9) In Example 4, the third communicating pipe 25 and the relief valve 26 are added to Example 1. However, the third communicating pipe 25 and the relief valve 26 may be added not only to Example 1 but also to Examples 2 to 4 and the modified examples (5) and (6) above. [Explanation of symbols]

[0031] 1 Gate body 1a Gate body drive arm 2a Upstream waterway 2b Downstream waterway 3 Double rod hydraulic cylinder 3a Front oil port 3b Rear oil port 4a Float 4b Float valve 4c Float device storage box 5 Door stop hardware 6 Hinge hardware 7 Trunnion bearing 8 Rod 9 End fitting 10 First connecting pipe 11 check valve 12 second communicating pipe 13 flow control valve 14 Hydraulic oil supply pipe 14a Supply connection port 15a Supply check valve 15b Discharge pilot check valve 16 hydraulic oil discharge pipe 16a discharge connection port 17 hydraulic pump 18 Hydraulic tank 19a Upstream water level 19b Downstream water level 21 Water level detection device 22 Oil pressure detection device 23 Hydraulic pump control device 24 Gate body openness detection device 25 Third connecting pipe 26 Relief valve

Claims

1. A hydraulic control device for a forced opening type gate that is closed by its own weight, A double-rod hydraulic cylinder having a rod that moves in conjunction with the movement of hydraulic oil, a front oil port, and a rear oil port; a door body that moves in a closing direction when the rod moves to the side where the front oil port is located and moves in an opening direction when the rod moves to the side where the rear oil port is located; a first communication pipe communicating between the front oil port and the rear oil port; a check valve provided in the first communication pipe and configured to allow hydraulic oil to flow only in a direction from the rear oil port to the front oil port; a second communication pipe that communicates the first communication pipe with a front side and a rear side of the check valve; a float valve that is provided in the second communication pipe and opens when the downstream water level downstream of the forced opening type gate reaches or exceeds a predetermined water level, and a flow control valve that adjusts the flow rate of the hydraulic oil so as not to exceed a predetermined flow rate; A hydraulic tank for storing hydraulic oil; a hydraulic pump for supplying hydraulic oil from the hydraulic tank to the double rod type hydraulic cylinder; a hydraulic oil supply pipe connecting a hydraulic oil outlet of the hydraulic pump and a front oil port side of the check valve of the first communicating pipe, or connecting the hydraulic oil outlet and a front oil port side of the float valve and the flow control valve of the second communicating pipe; A supply check valve provided in the hydraulic oil supply pipe; a hydraulic oil discharge pipe connecting the hydraulic tank and the rear oil port side of the check valve of the first communicating pipe or connecting the hydraulic tank and the rear oil port side of the float valve and the flow control valve of the second communicating pipe; A check valve with a discharge pilot provided in the hydraulic oil discharge pipe; A water level detection device that detects whether the downstream water level is equal to or lower than a specific water level; a hydraulic pressure detection device that detects whether or not the hydraulic pressure in the hydraulic oil supply pipe is less than a predetermined pressure; a hydraulic pump control device that operates the hydraulic pump when the water level detection device detects that the downstream water level is equal to or lower than the specific water level and the oil pressure detection device detects that the supply pipe oil pressure is lower than the predetermined pressure, and stops the hydraulic pump when the water level detection device detects that the downstream water level is not equal to or lower than the specific water level or the oil pressure detection device detects that the supply pipe oil pressure is not lower than the predetermined pressure, When hydraulic oil is supplied from the hydraulic tank to the double-rod hydraulic cylinder via the hydraulic pump, the hydraulic oil supply pipe, the supply check valve, the first connecting pipe, and the front oil port, hydraulic oil is discharged from the double-rod hydraulic cylinder to the hydraulic tank via the rear oil port, the first connecting pipe, the hydraulic oil discharge pipe, and the check valve with discharge pilot. A hydraulic control device comprising:

2. In the hydraulic control device according to claim 1, the hydraulic pressure detection device is replaced with a door body opening degree detection device that detects whether the opening degree of the door body is less than a predetermined opening degree, The hydraulic pump control device operates the hydraulic pump when the water level detection device detects that the downstream water level is equal to or lower than the specific water level and the door body openness detection device detects that the openness of the door body is less than the predetermined openness, and stops the hydraulic pump when the water level detection device detects that the downstream water level is not equal to or lower than the specific water level or when the door body openness detection device detects that the openness of the door body is not less than the predetermined openness. A hydraulic control device comprising:

3. a third communication pipe that communicates between the supply check valve and the hydraulic pump in the hydraulic oil supply pipe and between the discharge pilot-equipped check valve and the hydraulic tank in the hydraulic oil discharge pipe; a relief valve provided in the third communicating pipe, which allows hydraulic oil to flow from the hydraulic oil supply pipe to the hydraulic oil discharge pipe when the communicating pipe oil pressure in the third communicating pipe becomes equal to or higher than the predetermined pressure.

3. The hydraulic control device according to claim 1 or 2.

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