Flow control method of double-control discharge valve

Abstract

The invention relates to a flow control method for a dual-control discharge valve. The method comprises the steps of starting preparation, turning plate starting, rotary valve adjustment starting, turning plate readjustment and the like. According to the flow control method of the dual-control discharge valve, the discharge valve can quickly reach the set feeding flow in the starting stage; vibration is small in the working state, operation is stable, and flow control is reliable; and in a shutdown stage and a static state, the closing action is rapid, and the sealing effect is good.

Description

Technical Field

[0001] The present invention relates to a flow control method for a dual-control discharge valve, belonging to the technical field of material transportation. Background Art

[0002] Rotary feeders are generally only applicable to dust-like substances or small-particle bulk materials, but the jamming phenomenon is still relatively frequent. In particular, it is difficult to feed large-particle bulk objects without jamming. Moreover, it is difficult to deal with the jamming of the rotary valve, which has an adverse effect on production. Therefore, vibrating feeders are generally used for feeding large-particle materials, but vibrating feeders are noisy and not sealed.

[0003] For large-particle bulk materials, the way of direct connection through a chute has the highest passing performance, but it is difficult to control the flow rate. In the prior art, there is a dual-action feeder, which has two working modes of feeding. The first is rotary feeding through a rotary valve, and the second is direct feeding controlled by a flap. During the rotary feeding process, after the rotary machinery jams or fails and stops, the flap is actuated to open the standby direct pipe for feeding; although this dual-action feeder well solves the feeding function of the feeder, its feeding flow rate cannot be accurately controlled, and in the prior art, there is no method for using the dual-action feeder, especially no flow control method for the dual-action feeder during the whole process of starting, running, and stopping. Summary of the Invention

[0004] The technical problem to be solved by the present invention is: to overcome the above-mentioned technical drawbacks and provide a control method for a dual-action discharge valve that simultaneously has opening degree control and rotational speed control.

[0005] To solve the above-mentioned technical problem, the technical solution proposed by the present invention is: a flow control method for a dual-control discharge valve, comprising the following steps: Step 1: Startup preparation; the rotary valve is in a non-rotating state, and the flap opening is 0; the belt conveyor is started, and the electronic scale for weighing the material weight on the belt conveyor starts to work; Step 2: Start discharging; the flap opening increases, and through the weighing of the electronic scale, the material flow rate per unit time is obtained; until the set flow rate is reached, the flap opening no longer increases; if the flap opening increases to the maximum threshold and still fails to reach the set flow rate, proceed to the next step; the maximum threshold is half of the maximum opening of the flap; Step 3: Start the rotary valve and increase the rotational speed. At the same time, through the weighing of the electronic scale, the material flow rate per unit time is obtained; until the set flow rate is reached, the rotational speed of the rotary valve no longer increases; if the rotational speed of the rotary valve reaches the maximum value and still fails to reach the set flow rate, proceed to the next step; Step 4: The opening of the flap continues to increase, and the material flow rate per unit time is obtained through the weighing of the electronic scale; until the set flow rate is reached, the opening of the flap no longer increases.

[0006] A further improvement of the above solution is that: the flap is driven by a hydraulic cylinder, the pressure in the rodless cavity of the hydraulic cylinder is detected, if the detected pressure value P is less than or equal to the pressure threshold, it means that the double-control discharge valve is operating normally; otherwise, increase the opening of the flap until the pressure value P is less than or equal to the pressure threshold; during this process, if the material flow rate per unit time obtained through the weighing of the electronic scale exceeds the set flow rate, the rotary valve is controlled to adjust.

[0007] A further improvement of the above solution is that: the closing sequence of the double-control discharge valve is that first the flap closes, then the rotary valve stops, and finally the belt conveyor stops.

[0008] A further improvement of the above solution is that: the closing of the flap means that the flap resets to the state with an opening of 0; after the rotary valve stops rotating, delay for t seconds, or when the material flow rate per unit time obtained through the weighing of the electronic scale is 0, the belt conveyor stops.

[0009] The flow control method of the double-control discharge valve provided by the present invention can enable the discharge valve to quickly reach the set feeding flow rate in the startup stage; during the working state, it has small vibration, stable operation, and reliable flow control; during the shutdown stage and the static state, the closing action is rapid and the sealing effect is good. Description of the Drawings

[0010] Figure 1 It is a schematic structural diagram of the closed state of the discharge valve controlled by a preferred embodiment of the present invention.

[0011] Figure 2 It is a schematic structural diagram of the open state of the discharge valve controlled by a preferred embodiment of the present invention. Embodiment

[0012] Embodiment: The flow control method of the double-control discharge valve in this embodiment is applied to the discharge valve as shown in Figure 1 and Figure 2 This discharge valve includes: a silo 1, a rotary valve 2, a frequency converter 3, a flap 4, an oil cylinder 5, a displacement sensor 6, a pressure sensor 7, a belt conveyor 8, and an electronic scale 9; the frequency converter 3 is used to control the rotation speed of the rotary valve 2; the oil cylinder 5 is used to drive the flap 4, and the displacement sensor 6 is used to detect the extension length of the oil cylinder 5 to obtain the opening of the flap 4. The pressure sensor 7 is used to detect the pressure in the rodless cavity of the oil cylinder 5. The material in the silo 1 can fall onto the belt conveyor 8 through the rotary valve 2 and the flap 4; the electronic scale 9 is used to weigh the material weight on the belt conveyor 8 in real time.

[0013] Figure 1 The discharge valve is in the closed state. In this state, the outlet width corresponding to the rotary valve 2 is L1, the opening corresponding to the flap 4 is 0, the movable width of the opening corresponding to the flap 4 is L2, and the rotary valve 2 is stationary and does not rotate.

[0014] Figure 2 The figure shows the unloading valve in the open state. In this state, the outlet width of the rotary valve 2 is L1, the opening of the flap 4 is T, the remaining active width of the flap 4 is L2-T, and the total width of the discharge port of the unloading valve is L1+T.

[0015] The discharge valve opening state includes the following three opening states: State 1: The rotation speed of the rotary valve 2 is greater than 0; the flap 4 is not opened, and the opening T is equal to 0; the effective outlet width of the discharge valve is L1.

[0016] State 2: The rotation speed of the rotary valve 2 is equal to 0; the flap 4 is open, and the opening T is greater than 0; the effective outlet width of the dual-control unloading valve is T.

[0017] State three: the rotation speed of the rotary valve 2 is greater than 0; the flap 4 is open, and the opening T is greater than 0; the effective outlet width of the dual-control unloading valve is L1+T.

[0018] The flow control method of the dual-control discharge valve of this embodiment includes a start-up phase control method, an operation process control method and a shutdown phase control method. The rotation speed of the rotary valve 2 and the opening of the flap 4 are controlled simultaneously, specifically including the following steps: Step 1: Start preparation; Check the material level of silo 1. If there is no material, the discharge valve will not start; the rotary valve 2 is in a non-rotating state, and the opening of the flap 4 is 0; if material is unloaded, the belt conveyor 8 is started, and the electronic scale 9 for weighing the weight of the material on the belt conveyor 8 starts working; Step 2: Start unloading; the flap 4 is driven by the oil cylinder 5, and the opening increases. The material flow rate per unit time is obtained through the weighing and feedback of the electronic scale 9. The opening is detected by the displacement sensor 6 through PID control until the material flow rate reaches the set flow rate. The opening of the flap 4 will no longer increase and the start-up is completed; if the opening of the flap 4 increases to the maximum threshold and still fails to reach the set flow rate, the next step is entered; the maximum threshold is half of the maximum opening of the flap; Step 3: The rotary valve 2 is started and the speed is increased. At the same time, the speed of the rotary valve 2 is controlled by the weighing and feedback of the electronic scale 9 through PID control and the frequency converter 3; until the set flow rate is reached, the speed of the rotary valve 2 will no longer increase and the start-up is completed; if the speed of the rotary valve 2 reaches the maximum value and still fails to reach the set flow rate, proceed to the next step; Step 4: The opening of the flap 4 continues to increase, and it is weighed and fed back by the electronic scale 9; until the material flow rate reaches the set flow rate, the opening of the flap will no longer increase, and the startup is completed, and the discharge valve enters the operation control.

[0019] The purpose of the startup control is to quickly open the direct-through channel by the flap 4 so that the material flow rate quickly reaches the set value. At the same time, a certain control space for the flap 4 is reserved to facilitate timely adjustment in case of jamming or failure of the rotary valve 2.

[0020] The operation control of the discharge valve adopts an operation mode with pressure control priority on the premise of ensuring the flow rate. The purpose is to achieve that during the operation process of the discharge valve and the material flow process, the resistance is small, the equipment wear is small, and the service life is long.

[0021] Specifically: The pressure sensor 7 detects the pressure in the rodless cavity of the oil cylinder 5. If the detected pressure value P is less than or equal to the pressure threshold, it means that the dual-control discharge valve is operating normally; otherwise, the opening of the flap 4 is increased until the pressure value P is less than or equal to the pressure threshold; during this process, as the opening of the flap 4 increases, the material flow rate also increases. Therefore, if the material flow rate exceeds the set flow rate, the rotary valve 2 is controlled to adjust.

[0022] The closing sequence of the dual-control discharge valve is that first the flap 4 closes, then the rotary valve 2 stops, and finally the belt conveyor 8 stops. Closing the flap 4 means that the flap 4 is reset to the state with an opening of 0; after the rotary valve 2 stops rotating, after a delay of t seconds, or when the weighing by the electronic scale 9 shows that the material flow rate per unit time is 0, the belt conveyor 8 stops. The main purpose of the closing control is to ensure that the resistance of the flap 4 during the action is the smallest and the closing action is smooth.

[0023] The present invention is not limited to the above embodiments. All technical solutions formed by equivalent replacement fall within the protection scope required by the present invention.

Claims

1. A flow control method for a double-control discharge valve, characterized in that, It includes the following steps: Step 1: Startup preparation; The rotary valve is in a non-rotating state, and the flap opening is 0; The belt conveyor starts, and the electronic scale for weighing the material weight on the belt conveyor starts to work; Step 2: Start discharging; The flap opening increases, and through the weighing of the electronic scale, the material flow rate per unit time is obtained; When the set flow rate is reached, the flap opening no longer increases; If the set flow rate is still not reached when the flap opening increases to the maximum threshold, proceed to the next step; The maximum threshold is half of the maximum opening of the flap; Step 3: Start the rotary valve and increase the rotation speed. At the same time, through the weighing of the electronic scale, the material flow rate per unit time is obtained; When the set flow rate is reached, the rotation speed of the rotary valve no longer increases; If the set flow rate is still not reached when the rotation speed of the rotary valve reaches the maximum value, proceed to the next step; Step 4: The flap opening continues to increase, and through the weighing of the electronic scale, the material flow rate per unit time is obtained; When the set flow rate is reached, the flap opening no longer increases.

2. The flow control method of the dual-control discharge valve according to claim 1, characterized in that: The flap is driven by a hydraulic cylinder, and the pressure in the rodless cavity of the hydraulic cylinder is detected. If the detected pressure value P is less than or equal to the pressure threshold, it indicates that the double-control discharge valve is operating normally; Otherwise, increase the flap opening until the pressure value P is less than or equal to the pressure threshold; During this process, if the material flow rate per unit time obtained through the weighing of the electronic scale exceeds the set flow rate, control the rotary valve to adjust.

3. The flow control method of the dual-control discharge valve according to claim 1, characterized in that: The closing sequence of the double-control discharge valve is that first the flap closes, then the rotary valve stops, and finally the belt conveyor stops.

4. The flow control method of the dual-control discharge valve according to claim 3, characterized in that: The flap closing means that the flap resets to the state with an opening of 0; After the rotary valve stops rotating, delay for t seconds, or when the material flow rate per unit time obtained through the weighing of the electronic scale is 0, the belt conveyor stops.

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