CN106192931B - A kind of gallery automatic sand discharging device of more sand inlet sequence opening and closings - Google Patents

Abstract

The invention relates to an automatic sand discharge device for corridors with multiple sand inlets sequentially opened and closed, which belongs to the field of water conservancy project management. The set skateboards, the triggering members fixed in the middle of each slideboard in a horizontal and symmetrical manner, the traction mechanism that drives the slideboards to reciprocate longitudinally along the sand delivery corridor, the slideboard reset devices symmetrically arranged on both sides of the slideboards, and the exit gates; among them, the sand delivery The corridor is excavated and constructed on the riverbed upstream of the reservoir dam. One end of the sand conveying corridor is connected to the bottom of the reservoir dam, and this end passes through the bottom of the reservoir dam through the outlet gate. The rollers are arranged symmetrically, and the slide board moves back and forth longitudinally along the sand delivery corridor. When the device is running, the sand inlets are opened and closed sequentially, and only one sand inlet is opened to ensure that each sand inlet along the sand delivery corridor has the same water head when opened, which solves the problem that the remote sand inlet is easy to be blocked. The key issue.

Description

A corridor automatic sand discharge device with sequential opening and closing of multiple sand inlets

technical field

The invention belongs to the technical field of operation management of water conservancy projects, and in particular relates to an automatic sand discharge device for corridors with multiple sand inlets sequentially opened and closed.

Background technique

The shortage of water resources in Northwest my country seriously restricts the development of economy and society. The main and tributaries of the Yellow River in Northwest China and the inland rivers in Xinjiang have high sediment content and coarse sediment particle size, which have adverse effects on the effective operation and management of water conservancy facilities such as reservoirs and channels. Severe siltation has occurred, which directly threatens the safety of the Guanzhong Plain and can only reduce its design function; some small and medium reservoirs in Xinjiang may lose their effectiveness due to siltation within a few years; the water diversion channel will also reduce flow due to sediment siltation capacity, and the cleared silt accumulates to desertify the cultivated land. The famous water diversion project "Zhengguo Canal" in history diverted water from the Luohe River, and the agriculture in the irrigation area developed greatly, which once made the Qin State strong and unified the world. However, the "Zhengguo Canal" has long since been buried by sediment.

For a long time, engineering management, design and research units have been committed to the research and exploration of reservoir channel silt reduction and dredging measures. The sand washing tunnel and sand discharge corridor related to the present invention are commonly used devices.

Sand flushing tunnels: some reservoirs are equipped with sand flushing tunnels, for example, the Three Gorges Reservoir has 7 sand flushing tunnels in the main dam section, and 3 sandwashing tunnels in the underground power plant dam section. The inlet elevation of the sand flushing tunnel is generally higher than the initial river bed elevation and lower than the inlet elevation of the power station or water intake that needs its protection. As the sediment gradually deposits, when the silted sand surface is close to the inlet elevation, the outlet gate is opened to flush the sand , the initial sediment concentration of the flushing water flow is high, and then gradually decreases. After scouring, it is generally funnel-shaped, starting from the bottom elevation of the entrance of the sand-washing tunnel, forming a scouring funnel in front of the dam with the underwater dynamic angle of repose as the slope, which has a good effect on protecting the water inlet. Due to the limited scouring range, the sand-washing tunnel has little effect on large-scale scouring and sand discharge and maintaining the effective storage capacity of the reservoir.

Sand-discharging corridor: Tan Peigen's invention patent "self-discharging sand corridor, patent number NIOIOO397OA", proposed a self-discharging sand corridor. The patent consists of multiple corridors arranged in parallel, and multiple sand discharge mechanisms are arranged in sequence on the upper part of each corridor to form a network of sand discharge holes on the plane. The multiple corridors are centrally controlled by a unified outlet gate. This patent focuses on the design of the shape and structure of the sand discharge mechanism. No consideration is given to the impact of the effect of the water head of each sand discharge mechanism on the distance from the outlet gate, so that the farther away from the outlet gate, the smaller the inflow of the sand discharge mechanism, and the remote sand discharge mechanism will be damaged during operation. It is gradually silted up and affects the sand discharge effect.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art and provide an automatic sand discharge device for corridors with multiple sand inlets sequentially opened and closed. When the device is running, the sand inlets are opened and closed sequentially, and only one sand inlet is opened. , to ensure that each sand inlet along the sand delivery corridor has the same effect water head, which solves the key problem that the sand inlet at the far end is easy to be blocked; the sediment is automatically discharged by using the reservoir drop, saving energy, and the structure is simple and economical significantly.

The present invention proposes an automatic sand discharge device for corridors with multiple sand inlets opened and closed sequentially. The sliding plate, the trigger member fixed in the middle of the lower part of each sliding plate symmetrically arranged laterally, the traction mechanism driving the sliding plate to reciprocate longitudinally along the sand transport corridor, the sliding plate reset device symmetrically arranged on both sides of the sliding plate, and the exit gate; among them, the sand transporting corridor The channel is excavated and built on the riverbed upstream of the reservoir dam. The downstream end of the sand delivery corridor is connected to the bottom of the reservoir dam. This end passes through the bottom of the reservoir dam through the outlet gate. The upstream end of the sand delivery corridor is closed and located in the reservoir; the slide plate The four corners below are symmetrically provided with rollers, and the skateboard reciprocates longitudinally along the sand delivery corridor.

Features and effects of the present invention:

A slide board is set under the sand inlet of the sand delivery corridor. By controlling the opening and closing of the slide board, only one of all the sand inlets of the entire sand delivery corridor is opened, and the rest of the sand inlets are closed, so that the sand inlet of each sand inlet is opened. The acting water heads are all the same, and the inlet flow velocity is roughly equal, which solves the key problem of silting at the sand inlet at the far end of the common corridor. Utilizing the drop of the reservoir to automatically discharge sand, no additional power is needed; the device has simple structure, convenient operation, low operating cost, and has good social and economic benefits.

Description of drawings

Fig. 1 is a schematic longitudinal sectional view of the overall arrangement of the device of the present invention.

Fig. 2 (a) is the cross-sectional structure schematic diagram of device of the present invention,

Fig. 2(b) is a schematic diagram of a longitudinal section of a partial structure of the device of the present invention.

Fig. 3 is a schematic diagram of the triggering member of the device of the present invention, wherein: Fig. 3(a) is a top view structural diagram of the triggering member when the sliding plate is located directly below the sand inlet and the driving ball is just stuck, and Fig. 3(b) is a fully opened sliding plate 1. The top view structure schematic diagram when the trigger member releases the driving ball; Fig. 3 (c) is a top view structure schematic diagram of the positioning block, Fig. 3 (d) is a side view structure schematic diagram of the positioning block; Fig. 3 (e) is a top view structure of the telescopic rod Schematic diagram, Fig. 3(f) is a side view structural diagram of the telescopic rod.

Fig. 4 is the schematic diagram of the working state of the slide block reset device when the device of the present invention starts to open the sand inlet sequentially from the downstream, wherein: Fig. 4 (a) is a schematic diagram of the working state of the slide block reset device when the first sand inlet is opened, Fig. 4(b) is a schematic diagram of the working state of the slider reset device when the second sand inlet is opened, and Fig. 4(c) is a schematic diagram of the working state of the slider reset device when the third sand inlet is opened.

Detailed ways

An automatic sand discharge device for corridors with multiple sand inlets sequentially opened and closed according to the present invention will be described in detail below in conjunction with accompanying drawings 1 to 4 and embodiments. For the convenience of text description, it is agreed that the length L along the longitudinal direction of the sand transport corridor 1, the width B of the cross section of the sand transport corridor 1 in the transverse direction, and the height or thickness H in the vertical upward direction, and the size of each device number is added with the above characters The corresponding number marks in the attached drawings indicate that, for example, the length of the sand transport corridor 1 is L1 and the width is B1; and it is agreed that the upstream and downstream are divided according to the flow direction of the water flow, and the water flow flows from the upstream to the downstream, and the left and right banks face the downstream.

The structure of the device of the present invention is shown in Fig. 1, 2, and this device comprises that the top is provided with a plurality of sand delivery corridors 1 of sand inlets 3 (the length L1 and the net width B1 of the sand delivery corridor 1 should be determined according to engineering design, If only dredging in front of the dam is required, the length is on the order of 100m; if it is necessary to remove silt to maintain the storage capacity, it will be on the order of 1000m), the slide 4 arranged under each sand inlet 3 is in the middle of each slide 4 The laterally symmetrical trigger member 6, the traction mechanism that drives the slide 4 to reciprocate longitudinally along the sand delivery corridor 1, the slide reset device located symmetrically on both sides of the slide 4, and the exit gate Valve; wherein, the sand delivery corridor 1 is located in the reservoir The riverbed upstream of the dam (UB in Figure 1 is the upstream riverbed and DB is the downstream riverbed) is excavated and constructed, and the downstream end of the sediment delivery corridor 1 is connected to the bottom of the reservoir dam Dam, and this end passes through the reservoir dam through the outlet gate Valve At the bottom, the upstream end of the sand delivery corridor 1 is closed and located in the reservoir, and there is silt at the top of the silt delivery corridor 1 (DS is the upper surface of the silt sediment in Figure 1); the four corners below the slide plate 4 are symmetrically provided with rollers 11 , the slide plate 4 reciprocates longitudinally along the sand delivery corridor 1 .

The cross-section of the described sand transport corridor 1 is a composite section of upper rectangle, lower trapezoid or semicircle, as shown in Figure 2 (a) (Fig. 2 (a) is the cross section of the lower trapezoidal sand transport corridor 1 ), the shape and size of this cross-section remain unchanged along the longitudinal direction of the sand delivery corridor 1, the longitudinal section of the sand delivery corridor 1 is shown in Figure 2(b), in the figure V represents the flow direction of the water flow, and the arrow points downstream; The upper surface of the straight cover plate 2 at the top of the corridor 1 is flush with the surface of the river bed, and the two sides of the cover plate 2 protrude from the side wall of the sand transport corridor 1, forming a closed sand transport corridor 1 with the composite section. Rectangular sand inlets 3 (length×width: L3×B3) are sequentially arranged at a certain distance along the sand delivery corridor on the board 2 (the distance between sand inlets is designed according to the sand discharge requirements). When each sand inlet 3 is opened, All have the same effect water head; a slide plate 4 is correspondingly arranged below each sand inlet 3, and the length of the slide plate 4 is 1.2 times of the length of the sand inlet 3, and the width is 1.1 times of the width of the sand inlet 3 (that is, L4×B4= 1.2L3 * 1.1B3), ensure that the sand inlet 3 can be completely closed, and the width B4=0.95B1 of the slide plate 4 in the present embodiment can calculate the width B3=0.86B1 of the sand inlet; A plurality of corbels 13 are arranged on the inner side walls according to a certain distance (the specific size should ensure that the slide rail 12 does not bend and sag after being loaded). Upward reciprocating movement; Arrange forward trigger block 7 (its plan view is trapezoidal, wider side is positioned at upstream) on the side walls of sand transport corridor 1 upstream of each sand inlet 3, its longitudinal position is far from sand inlet 3 The center is the length of a slide plate 4; the reverse trigger block 27 (its size is the same as the forward trigger block, the The wider side is located downstream), its longitudinal position is located at the center of the sand inlet 3, the height of the two kinds of trigger blocks is flush with the trigger member 6, and the width of the wide side is 0.02B1.

The minimum flow velocity in the sand delivery corridor 1 should be greater than the maximum starting velocity V _D of the sediment, and the maximum flow velocity can be 2 to 3 times the minimum flow velocity; among them, g is the acceleration of gravity, D is the particle size of the sediment, and H is the total operating head (that is, the difference between the upstream water level of the reservoir and the elevation of the valve center of the outlet gate).

The traction mechanism includes two drive balls 5, two traction cables 8, four fixed pulleys 9 and a hoist 10; wherein, the two drive balls 5 are strictly parallel and are respectively fixed on two traction cables 8; The fixed pulleys 9 are fixed in pairs at both ends of the sand delivery corridor 1, and their height is flush with the trigger member; the hoist 10 is located on the top of the reservoir dam Dam; 8. First, go around the fixed pulley at the downstream end of the sand delivery corridor from the winch 10 on the top of the reservoir dam, pass through the trigger member under the slide plate 4 in turn, then turn around the fixed pulley at the upstream end of the sand delivery corridor, and turn back from the rollers 11 at the four corners of the slide plate. Pass above, and then wind back to the hoist 10 from the fixed pulley at the downstream end of the sand delivery corridor, and finally form an endless traction cable 8 with constant length and reciprocatingly pulling the driving ball 5 .

Described triggering member 6 is laterally symmetrically fixed on the middle part below each slide plate 4, and its structure is shown in Figure 3 (only the triggering member that is positioned at one side below the slide plate is shown in the figure, and the other side is not shown), including positioning block 14, belt There are telescopic rods 17 and pressure springs 18 of rollers 19; wherein, the positioning block 14 is rectangular, fixed on the side of the middle part below the slide plate 4, near the side wall 21 of the sand transport corridor, the outside of the positioning block 14 is larger than that of the slide plate 4 The width of the wide side of the outer indentation trigger block is horizontally milled into an inverted T-shaped slot in the middle of the upper plane of the positioning block (as shown in 14-1, 14-2 in Figure 3 (c), (d), and the pressure Spring 18 is put into the horizontal inner section 14-1 of T-shaped groove, telescopic rod 17 is put into the lateral lateral section 14-2 of T-shaped groove, and telescopic rod 17 rear end is close to pressure spring 18, and then the upper plane of positioning block 14 Riveted with the lower plane of the slide plate, the slide plate and 14-1 and 14-2 form a closed cavity, and the telescopic rod 17 and the spring 18 can slide laterally in this cavity; One side of the wall is longitudinally symmetrically provided with a conical horn hole 15 with a large mouth outward (as shown in Figure 3 (c)), which is convenient for guiding the drive ball 5 fixed on the traction cable 8 to enter smoothly, and is located at the longitudinal inner side of the horn hole 15 There is a cylindrical hole 16 just for the drive ball 5 to pass through and concentric with the horn hole 15. The diameter of the cylindrical hole 16 is equal to the small diameter of the horn hole 15; the telescopic rod 17 is a transverse inner section 17-2 and a transverse outer section 17- 3 constitutes an inverted T shape, and the rod end (that is, the outer end) near the side wall 21 of the sand delivery corridor is provided with a groove 19-2 for installing a roller 19 and a wheel shaft hole 17-1 (as shown in Figure 3(e)) After the wheel shaft 19-1 is inserted into the wheel shaft hole 17-1 and riveted, the middle part of the telescopic rod 17 is provided with a cylindrical hole 20 just for the drive ball 5 to pass through, and the height of the center of the hole is flush with the center of the horn hole 15 of the positioning block 14; The traction cable 8 passes through the trumpet hole 15 of the positioning block 14 , the cylindrical hole 16 and the cylindrical hole 20 in the middle of the expansion rod 17 .

According to the change of the relative position of the slide plate 4 and the sand inlet 3, the relative positional relationship between the internal components of the trigger member 6 is described as follows:

When the slide plate 4 is located directly below the sand inlet 3 (as shown in Figure 3(a)), the sand inlet 3 is closed, the forward trigger block 7 is upstream of the slide plate 4, and the reverse trigger block 27 is located longitudinally at the sand inlet. In the center, the driving ball 5 has entered the horn hole 15 of the positioning block 14, and the telescopic rod 17 protrudes toward the direction close to the side wall 21 under the action of the pressure spring 18, but its laterally outer section 17-3 is close to the position of the positioning block 14. The transverse middle section 14-2 of the T-shaped groove will not continue to stretch out; the cylindrical hole 20 in the middle of the telescopic rod 17 and the cylindrical hole 16 in the middle of the positioning block 14 are laterally misaligned (the misalignment width is 0.002B4 in this embodiment) , blocks the drive ball 5, and pulls the slide plate 4 upstream under the action of the traction cable 8;

When the slide plate 4 left the sand inlet 3 and made it about to be fully opened (as shown in Figure 3 (b)), the outer end roller 19 of the telescopic rod 17 began to contact the forward trigger block 7, and the forward trigger block 7 inclined-plane Squeeze the telescopic rod 17 to retreat gradually and reversely push the pressure spring 18. When the cylindrical hole 20 in the middle of the telescopic rod 17 is aligned with the cylindrical hole 16 of the positioning block 14, the driving ball 5 enters the cylindrical hole 20 (this embodiment Taking the slope of the forward trigger block 7 as 2:1, the roller 19 at the outer end of the telescopic rod 17 starts to contact the cylindrical hole 20 in the middle of the forward trigger block 7 to the telescopic rod 17 and the cylindrical hole 20 of the positioning block 14. The aligned length of the hole 16 is 0.004B4), the slide plate 4 stays at the position where the sand inlet 3 is fully open, and the sand inlet discharges sand (see position B in Figure 1; the sand inlet at position A has completed sand discharge, and the top forms sand funnel, and the slide plate 4 in this position has been reset to the closed position); the traction cable 8 pulls the driving ball 5 and moves to the next slide plate 4.

The sliding plate resetting device includes a plurality of linkage ropes positioned on both sides of the slide plate, a fixed pulley 22 (as shown in Fig. ); wherein, after the two ends of each linkage rope bypass the fixed pulley 22, they are respectively fixed on two adjacent slide plates, and the fixed pulley 22 is positioned at the downstream oblique side of the sand inlet, 0.5L4 length; when two adjacent slides are located directly below the sand inlet to close the two sand inlets, the linkage rope fixed between the two slides is in a loose state.

Fig. 4 has illustrated the process that slide plate 4 is pulled back to the closed state of sand inlet 3 with linkage rope:

The linkage rope 23 is arranged symmetrically on both sides of the slide plate 4, and only one side is shown in the figure, and the other side is not shown. The initial working condition of this device is that all the sand inlets 3 of the sand delivery corridor 1 are closed by the slide plate 4, and the driving ball 5 is located downstream of the first sand inlet 3-1 in front of the reservoir dam (Fig. 4(a) left side), the drive balls 5 on both sides are strictly parallel; when sand discharge starts, the outlet gate Valve is opened, the winch 10 is started, and the traction steel cable 8 pulls the drive ball 5 to move upstream (the right side of Fig. 4(a)), to When the first slide 4-1, the drive ball 5 is stuck, pull the slide 4-1 to gradually open the sand inlet 3-1, pull the linkage rope 23-1 at the same time, and bypass the fixed pulley 22 to tighten the linkage rope 23-2 ; When the slide plate 4-1 arrived at the fully open position of the sand inlet 3-1, the linkage rope 23 also just straightened, and the drive ball 5 just passed the cylindrical hole 20 of the telescopic rod 17 to move on, and the slide plate 4-1 Then stay at the fully open position of the sand inlet 3-1, see Fig. 4 (a); the traction steel cable 8 pulls the drive ball 5 and continues to move upstream, reaches the second slide plate 4-2 and pulls it apart, synchronously pulling Long interlocking rope 24-1, tightening interlocking rope 24-2; Because the first group of interlocking rope 23 is tensioned originally, when second slide plate 4-2 moves upstream, because the length of every interlocking rope is constant , the linkage rope 23 is pulled counterclockwise, and the first slide plate 4-1 is pulled back to the position of closing the first sand inlet 3-1, and the telescopic rod is also in the state of stretching out under the effect of the pressure spring 18, see Fig. 4 (b); Continue the same operation, the sand inlet 3-3 is opened, the slide plate 4-2 is pulled back to the position of closing the sand inlet 3-2, the linkage rope 23 returns to a relaxed state, and the linkage rope 25 is tensioned, see Figure 4(c).

The traction cable 8 pulls the driving ball 5 to move toward the upstream of the reservoir, and opens each sand inlet 3 in turn, and always keeps only one sand inlet 3 open for sand discharge, and the rest of the sand inlets 3 are reset and closed under the action of the linkage rope. , which solves the key problem of silting at the sand inlet 3 at the far end of the common sand delivery corridor 1.

After the driving ball 5 reaches the upstream end of the sand delivery corridor 1 and opens the farthest sand inlet 4, the driving ball 5 passes through the trigger member of the farthest slide plate 4; A pressure spring 28 (as shown in Figure 1) is installed in it, when the trigger member releases the drive ball 5, the pressure spring 28 pushes the slide plate 4 downstream a small distance, so that the rod end roller of the telescopic rod 17 is separated from the forward trigger. Block 7, the telescopic rod 17 returns to the outstretched state; the hoist 10 runs in reverse and pulls the drive ball 5 back, and the drive ball 5 is blocked by the trigger member of the slide plate 4 at the upstream end of the sand transport corridor, and then the slide plate is pulled back to the sand transport gallery Right below the sand inlet 3 at the upstream end of the road, at the same time, the reverse trigger block 27 squeezes the telescopic rod 17, releases the drive ball 5, and the slide plate 4 at the upstream end of the sand delivery corridor stays directly under the sand inlet 3 at the upstream end to close it , continue to pull the driving ball 5 downstream, because when the slide plate 4 resets, the telescopic rod 17 has stretched out, and the cylindrical hole 20 in the middle is misaligned with the cylindrical hole 16 of the positioning block 14, and the driving ball 5 is pulled back to the sand inlet 3. When the central position is stuck, the outer end roller 19 of the telescopic rod 17 also contacts the reverse trigger block 27, and the telescopic rod 17 is gradually retracted under the extrusion of the reverse trigger block 27 slope, when the cylinder in the middle of the telescopic rod 17 When the shaped hole 20 is aligned with the cylindrical hole 16 of the positioning block 14, the driving ball 5 passes through the trigger member and continues to move downstream, and the slide plate 4 stays at the position downstream of the sand inlet 3 (0.004B4). Due to the length of the slide plate 4 It is 1.2 times the length of the sand inlet 3 (B4=1.2B3), and the downstream side (0.004B4) can also completely close its corresponding sand inlet 3. The driving ball 5 passes through the trigger member of each slide plate one by one, and the driving ball 5 finally gets back to the position in front of the dam, waiting for the next sand discharge.

The sand discharge time of each sand inlet 3 is determined by the sand discharge effect. When the silt accumulated above the sand inlet 3 is basically discharged and the sand content of the sand discharge flow is significantly reduced, it is exchanged to the next sand inlet 3. sand. The sand discharge time of each sand inlet 3 is roughly the moving time of the drive ball 5 between the two sand inlets 3, which can be controlled by adjusting the speed of the hoist 10; if a single sand inlet 3 requires a longer sand discharge time , can also stay for a certain period of time when the driving ball 5 is positioned between two sand inlets 3 .

In this embodiment, the clear width B1 at the upper mouth of the sand transport corridor 1 (Fig. 2) is designed to be 1.6m, the height of the rectangle is 0.7m, the height of the trapezoid is 1.0m, the width of the bottom is 0.6m, the water flow area is 2.22m ² , and the sand transport The flow velocity in the corridor is 2.50m/s, the sand discharge flow rate is 5.55m ³ /s, the width of the sand inlet 3 is B3=0.86B1=1.38m, the length is L3=1.6m, and the inlet area of the sand inlet 3 is 2.20m ² . Thus the size of the slide plate 4 can be calculated, width B4=1.1B3=1.52m, length L4=1.2L3=1.92m. The interval between each sand inlet 3 is set to be 20m, and 50 sand inlets are arranged, which can remove the silt deposited within 1000m in the reservoir.

The device is suitable for elongated reservoirs. If the sand discharge device of the present invention is built synchronously on the reservoir bed during reservoir construction, when the silt thickness of the designed dead storage capacity is 20m, the underwater dynamic repose angle of silt silt is 30 degrees, and when a certain silt thickness is For sand discharge, the effective width of sand discharge can be maintained at about 70m.

For large reservoirs, multiple sets of independent devices can be arranged in front of the dam. For example, the underground power plant on the right bank of the Three Gorges has built three sand washing tunnels. Continue the goal of flushing sand.

Claims (8)

1. An automatic sand discharge device for corridors with multiple sand inlets opened and closed in sequence, characterized in that the device includes a sand delivery corridor with a plurality of sand inlets on the top, a slide plate arranged below each sand inlet , the triggering member fixed in the middle of each slide plate in a horizontal and symmetrical manner, the traction mechanism that drives the slide plate to reciprocate longitudinally along the sand transport corridor, the slide plate reset device symmetrically located on both sides of the slide plate, and the exit gate; wherein, the sand transport corridor is in The upper reaches of the reservoir dam are excavated and constructed on the river bed. The downstream end of the sand delivery corridor is connected to the bottom of the reservoir dam. The downstream end of the sand delivery corridor passes through the bottom of the reservoir dam through the outlet gate. Inside; the four corners below the slide plate are symmetrically provided with rollers, and the slide plate moves back and forth longitudinally along the sand transport corridor. 2. The automatic sand discharge device for the corridor with multiple sand inlets opened and closed sequentially according to claim 1, wherein the cross section of the sand conveying corridor is a composite cross section of upper rectangle, lower trapezoid or semicircle , the top of the sand conveying corridor is a straight cover plate, the upper surface of which is flush with the surface of the river bed, and the two sides of the cover plate protrude from the side wall of the sand conveying corridor; Springs; the sand inlets are arranged at certain intervals along the cover plate in the longitudinal direction of the sand delivery corridor. The sand inlets are rectangular, and each sand inlet has the same effect when opened separately; Set multiple corbels at a certain distance, install slide rails on the corbels, and the rollers at the four corners below the slide plate reciprocate on the slide rails; symmetrically arrange on both sides of the sand delivery corridor upstream and downstream of each sand inlet For the trigger block, the longitudinal position of the upstream positive trigger block is the length of a slide plate from the center of the sand inlet, and the downstream reverse trigger block is located at the center of the sand inlet, and the height of the trigger block is flush with the trigger member. 3. The automatic sand discharge device for the corridor with multiple sand inlets opened and closed in sequence according to claim 2, wherein the minimum flow velocity in the described sand delivery corridor is greater than the maximum starting velocity of sediment, and the maximum flow velocity is taken as the minimum flow velocity 2 to 3 times of that. 4. The automatic sand discharge device for corridors with multiple sand inlets opened and closed sequentially as claimed in claim 1, wherein the slide plate is rectangular, its length is 1.2 times the length of the sand inlet, and its width is 1.1 times the width of the sand inlet, so that when the slide is located directly below the sand inlet, the sand inlet is completely closed. 5. The automatic sand discharge device for corridors with multiple sand inlets opened and closed sequentially according to claim 2, wherein the traction mechanism is composed of two drive balls, two traction cables, four fixed pulleys and a hoist Among them, two driving balls are strictly parallel and fixed on two traction cables respectively; four fixed pulleys are fixed in pairs at both ends of the sand delivery corridor, and their height is flush with the triggering member; The top of the dam; the traction steel cable is located on both sides of the sand delivery corridor. The traction cable goes from the winch on the top of the reservoir dam to the fixed pulley at the downstream end of the sand delivery corridor, passes through the trigger member under the slide plate in turn, and bypasses the sand delivery corridor The fixed pulley at the upstream end turns back, passes over the rollers at the four corners of the skateboard, and then winds back to the winch from the fixed pulley at the downstream end of the sand delivery corridor, finally forming an endless traction cable with constant length and reciprocating pulling of the driving ball. 6. The automatic sand discharge device for the corridor with multiple sand inlets opened and closed sequentially according to claim 5, wherein the trigger member includes a positioning block, a telescopic rod with rollers and a pressure spring; wherein, the positioning The outer side of the block close to the side wall of the sand transport corridor is indented laterally by the distance of the longer and wider side of the trigger block than the outer side of the slide plate. The positioning block is horizontally milled to place the expansion rod and the pressure spring. The closed cavity is formed by the slide plate and the horizontal milling groove of the positioning block. The telescopic rod and the pressure spring slide in the closed cavity. On the side of the positioning block close to the side wall of the sand washing corridor, a conical horn with a large mouth facing outward is arranged longitudinally and symmetrically. The hole and the cylindrical hole concentric with the horn hole are used for the traction cable and the driving ball to pass through; the outer end of the telescopic rod is provided with a groove for installing rollers and a wheel axle hole, the rear end of the telescopic rod is close to the pressure spring, and the middle part of the telescopic rod There is a cylindrical hole for the traction cable and the driving ball to pass through. The diameter of the cylindrical hole is equal to the cylindrical hole of the positioning block and the height is consistent. Under the thrust of the pressure spring, it is transverse to the cylindrical hole of the positioning block. Misaligned, but under the squeeze of the trigger block will be concentric with the cylindrical hole of the positioning block to allow the drive ball to pass through. 7. The automatic sand discharge device for corridors with multiple sand inlets sequentially opened and closed according to claim 1, wherein the slide reset device includes a plurality of linkage ropes located on both sides of the slide, and each linkage rope The fixed pulleys are matched and fixed at the bottom of the cover plate of the sand delivery corridor; wherein, after the two ends of each linkage rope bypass the fixed pulleys matched with it, they are respectively fixed on the two adjacent sliding plates, and the fixed pulleys are located at the entrance. The oblique side of the downstream of the sand mouth; the slide plate reset device forms a linkage under the drive of the traction mechanism to reset the slide plate. 8. The automatic sand discharge device for the corridor with multiple sand inlets opened and closed in sequence according to claim 1, wherein the outlet gate controls the outlet flow of the sand discharge device to meet the design flow velocity in the sand delivery corridor. Requirements; select opening and closing times according to the sand discharge plan.