Bulk material hopper capable of preventing longitudinal tearing of belt and material flow control method

Abstract

The invention discloses a bulk cargo hopper capable of preventing a belt from being torn longitudinally and a material flow control method.The bulk cargo hopper comprises a hopper body, the hopper body is provided with an upper feeding port and a lower discharging port, and the bulk cargo hopper is characterized in that a hopper side face first-stage discharging port is formed in the bottom of the hopper body from bottom to top; a buffer area communicated with the hopper side face first-stage discharging port is arranged on the outer side of the hopper side face first-stage discharging port of the hopper body, and the buffer area is a cavity which is closed in the circumferential direction and open in the upper portion and the lower portion. And a hopper side surface secondary discharge hole is formed in the front end of the buffer area. According to the hopper, the buffer area is arranged on the outer side of the hopper body, the upper portion of the buffer area is open, strong positive pressure of materials above foreign matter on the foreign matter is eliminated, and therefore the situation that the foreign matter is inserted into a belt to cause longitudinal tearing of the belt is avoided.

Description

Technical Field

[0001] The invention relates to the field of bulk cargo operations at port terminals, in particular to a bulk cargo hopper. Background Art

[0002] Bulk cargo hoppers are usually used in bulk cargo operations at port terminals. Although seemingly simple, bulk cargo hoppers play a key role in connecting the upper and lower parts of bulk cargo operations and have a significant impact on production efficiency. Bulk cargo hoppers have two main functions: one is to receive bulk cargo from grab equipment such as gantry cranes or ship unloaders and temporarily store bulk cargo; the other is to evenly feed materials to the belt conveyor below the bulk cargo hopper through the hopper mouth.

[0003] The main structure of the bulk hopper is usually a four-sided metal structure with a large upper opening and a small lower opening. The upper opening is the feed opening, which is generally 6 to 8 meters square and is used to receive the materials from the grab bucket. The lower opening is the discharge opening, which is generally 0.4 to 1.2 meters wide (determined by the width of the belt conveyor below the hopper, usually less than two-thirds of the belt width), and is used to feed the belt conveyor below. The hopper height is usually between 8 and 10 meters. The middle hopper is used to temporarily store bulk materials.

[0004] At present, in bulk cargo operations at port terminals, the feed port (upper port) of the bulk cargo hopper is generally square, and the discharge port (lower port) structure mainly has two forms: fixed size (rectangular) form and openable and closable form.

[0005] In actual use, the feed port and the bucket body have few faults and are easy to maintain. The discharge port has a great impact on production operations, has many faults, and is difficult to maintain. Therefore, the present invention focuses on the structure and flow control of the discharge port.

[0006] Advantages and disadvantages of bulk hoppers with fixed size outlets:

[0007] Advantages: The discharge port has a simple and stable structure, low manufacturing and maintenance costs, and simple and easy maintenance.

[0008] shortcoming:

[0009] 1. The flow rate of the discharge port cannot be controlled. It is actually just a straight-through hopper. It is usually not used to feed belt conveyors, but is used in the process of feeding dump trucks.

[0010] 2. There is no temporary material storage function. Because the discharge port is of fixed size and cannot be opened or closed, there is no temporary material storage function. The material flow can only be controlled by the crane grab (operated by the driver), which has a great impact on production efficiency.

[0011] Advantages and disadvantages of bulk hopper with openable and closable discharge port:

[0012] This structure can adjust the material flow rate by changing the width of the discharge port through an additional opening and closing mechanism set at the discharge port, and control the material flow rate to meet the operating requirements of the maximum load of the belt conveyor.

[0013] advantage:

[0014] 1. Control the flow rate of the discharge port. An opening and closing mechanism is set at the discharge port to adjust the material flow rate by changing the width of the discharge port. The opening degree can be adjusted according to the material characteristics, such as material bulk density, viscosity, particle size, etc., to prevent the belt conveyor from being overloaded due to excessive flow.

[0015] 2. The bulk hopper has a temporary storage function. When the discharge port is in a closed state, the hopper has the function of temporarily storing materials. The discharge port can be opened and closed according to on-site needs to meet production needs.

[0016] shortcoming:

[0017] 1. There is a risk of longitudinal tearing of the belt. In bulk cargo operations, special-shaped materials are sometimes mixed into the materials. When the size of the special-shaped materials is larger than the maximum width or height of the discharge port and is stuck at the discharge port (inside the hopper) (it is difficult to be discovered), the belt conveyor below is still running. Under the strong material pressure in the hopper, the belt will be torn longitudinally over a long distance. This phenomenon often occurs in production operations, causing production interruptions and large machine losses.

[0018] 2. Blockage at the discharge port. When handling materials with larger bulk density (common bulk density of materials in ports: coal 0.85~1.0t / m 3 , sand and gravel building materials 1.3~1.6t / m 3 , metal ore 2.0~2.5t / m 3 ), in order to prevent the belt conveyor from overloading, it is necessary to reduce the width of the discharge port and reduce the flow rate. At this time, the material is easy to arch at the discharge port and cause blockage. If the material is more viscous, the blockage is more obvious.

[0019] 3. Unstable flow control at the discharge port. In the port, it is necessary to adapt to the operation of various materials. The physical properties of various materials are quite different, such as bulk density, viscosity, moisture content, particle size, etc. In order to ensure that the belt conveyor is not overloaded, the discharge flow at the hopper port needs to be relatively stable to maximize the production efficiency and ensure that the belt conveyor is neither overloaded nor underloaded. The existing discharge port structure realizes flow control by changing the width of the discharge port. The flow control is not stable enough, and overload and discontinuous feeding may occur from time to time. Summary of the invention

[0020] The technical problem to be solved by the present invention is to provide a bulk cargo hopper and a material flow control method which can prevent the longitudinal tearing of the belt.

[0021] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0022] The present invention first provides a bulk cargo hopper that can prevent belt longitudinal tearing, including a hopper body, wherein the hopper body has an upper feed port and a lower discharge port, and a primary discharge port is opened on the side of the hopper body from the bottom upward; a buffer zone connected to the primary discharge port is arranged outside the primary discharge port of the hopper body, and the buffer zone is a cavity that is closed circumferentially and open at the top and bottom; a secondary discharge port is arranged at the front end of the buffer zone.

[0023] The secondary discharge port is provided with a secondary discharge port regulating plate, and the secondary discharge port regulating plate is used to adjust the height of the secondary discharge port (ie the thickness of the material layer).

[0024] The buffer zone comprises two buffer zone side panels, and the two buffer zone side panels are coplanar with the hopper body side panels.

[0025] The height of the buffer zone side panel is higher than the height of the primary discharge port.

[0026] The buffer zone also includes a buffer zone front panel, and the secondary discharge port is located on the buffer zone front panel; the buffer zone front panel, two buffer zone side panels and the hopper body front side panel enclose the buffer zone.

[0027] A height adjustment hole is arranged on the front panel of the buffer zone along the height direction, and the secondary discharge port adjustment plate is adjusted up and down on the front panel of the buffer zone through the height adjustment hole.

[0028] The buffer zone is integrated with the hopper body.

[0029] The width of the secondary discharge port is less than two-thirds of the belt width.

[0030] The present invention also provides a material flow control method, which calculates the secondary discharge port height according to the material bulk density, belt running speed, maximum design flow of the belt conveyor and a practical correction value, and controls the material flow by the secondary discharge port height.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. The hopper of the present invention is provided with a buffer zone at the front end of the hopper body, and the top of the buffer zone is open, thereby eliminating the strong positive pressure of the material above the foreign matter on the foreign matter, thereby preventing the foreign matter from inserting into the belt (the foreign matter is not strong enough to insert into the belt under the action of its own weight) and causing the belt to tear longitudinally.

[0033] 2. The hopper of the present invention is provided with a secondary discharge port at the front end of the buffer zone to adjust the discharge height, control the material flow rate, and prevent the belt conveyor from overloading; the material flow rate control is also more stable and accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Schematic diagram of belt tearing caused by foreign matter blocking the belt in height direction;

[0035] Figure 2 Test diagram;

[0036] Figure 3 Structural diagram of bulk cargo hopper mouth to prevent belt longitudinal tearing;

[0037] Figure 4 Left view of the hopper outlet (half-section view);

[0038] Figure 5 Schematic diagram of foreign matter eliminating the positive pressure above through the first-level discharge port;

[0039] Figure 6 Correspondence diagram between material bulk density and secondary discharge port height;

[0040] Among them: 1- hopper body; 2- discharge port below the hopper; 3- primary discharge port; 4- secondary discharge port; 5- secondary discharge port adjustment plate; 6- buffer zone (ABCDEF encircled area); 7- belt; 8- foreign matter; 9- adjustment plate base; 10- long strip adjustment hole; 11- bolt.

[0041] h-height of the secondary discharge port; A1-height of foreign matter; H-height of the primary discharge port; K-height of the discharge port side plate; B1-width of the lower discharge port. DETAILED DESCRIPTION

[0042] like Figure 1 In a conventional hopper, if the particle size of foreign matter mixed in the material is larger than the width or height (h0) of the discharge port, regardless of its length or width, it will be stuck at the discharge port. Combined with the positive pressure of the material in the hopper, it will cause a longitudinal tearing accident of the belt during operation.

[0043] In order to solve the problem of longitudinal belt tearing during operation, the applicant conducted the following test, see Figure 2 : Putting foreign objects of the same size (found in production) or even larger and heavier objects on the same belt conveyor will not insert into the belt, but will move forward with the running belt, without causing longitudinal tearing of the belt. The reason for this is that in addition to its own weight, the foreign objects have no strong additional pressure, so they will not insert into the belt. At the same time, the foreign objects move with the belt, and there is no relative movement between them, so longitudinal tearing of the belt is avoided.

[0044] In order to achieve the above test results, the applicant set a buffer zone outside the hopper to form the technical solution of the present invention. Figure 3As shown, the discharge port structure of the bulk cargo hopper for preventing belt longitudinal tearing of the present invention comprises a hopper body 1, and a buffer zone 6 is connected to the bottom of the hopper body 1 through a primary discharge port 3, and the buffer zone 6 is an area surrounded by ABCDEF. The buffer zone 6 is made of a steel plate or other materials that meet the requirements of bulk cargo. The buffer zone 6 and the hopper body 1 are formed into a whole by welding or other means. The lower part of the whole is the discharge port 2, and the upper part of the buffer zone 6 is open. A secondary discharge port 4 is arranged in front of the buffer zone 6, and a secondary discharge port adjustment plate 5 is installed on the secondary discharge port 4. The secondary discharge port adjustment plate 5 can be adjusted up and down. By adjusting the secondary discharge port adjustment plate 5 up and down, the discharge port height of the secondary discharge port 4 can be adjusted, thereby controlling the material layer thickness and realizing material flow control.

[0045] In one embodiment, an adjustment plate base 9 is welded on the side panel of the buffer zone 6, and a long strip adjustment hole 10 is opened on the adjustment plate base. The secondary discharge port adjustment plate 5 is fixed to the adjustment plate base 9 by a bolt 11 passing through the long strip adjustment hole 10.

[0046] The outlet structure proposed by the present invention has a buffer zone to eliminate the positive pressure above the foreign matter, such as Figure 5 .

[0047] Try to eliminate the positive pressure above the foreign matter 8 in the material, so that the foreign matter 8 can enter the buffer zone 6 through the primary discharge port 3 (such as Figure 3 ), reaches the outside of the first-level discharge port 3 on the side of the hopper, and the buffer zone 6 is Figure 3 The upper part of the buffer zone 6 is open, which eliminates the strong positive pressure of the material above the foreign object on the foreign object, thereby preventing the foreign object from being inserted into the belt (the foreign object is not strong enough to be inserted into the belt under the action of its own weight).

[0048] In order to allow foreign matter 8 in the material to pass through the primary discharge port 3, the height of the primary discharge port 3 must be raised. However, if the primary discharge port 3 is raised, the material flow rate will be too large, which will cause the belt conveyor to overload. Therefore, a secondary discharge port 4 is set at the rear end to limit the discharge height to ensure that the belt conveyor is not overloaded. The small amount of material cut from the primary discharge port 3 to the secondary discharge port 4 will be stored in the buffer zone for a short time. Practical operation has proved that due to the internal force between bulk materials, the cut bulk materials will only be stored for a short time and will not overflow. Figure 5 .

[0049] The function of the primary discharge port 3 is to allow foreign matter to pass through and reach the buffer zone 6, thereby eliminating the positive pressure above the foreign matter and preventing the belt from tearing longitudinally; the function of the secondary discharge port 4 is to ultimately achieve material flow control.

[0050] In actual applications, the unstable material flow phenomenon often occurs in metal mining operations with large bulk density, small particle size, high water content, high viscosity, and poor fluidity, such as powdered metal ore. In addition to the objective factors of the material itself, it is also related to the structure of the hopper mouth. As analyzed above (see Figure 3 , Figure 4 ), the material flow control of the commonly used openable and closable bulk hopper is achieved by changing the width of the discharge port B1. In practice, it is found that the width of the discharge port is positively correlated with the material passability (smoothness) and material flow rate. In other words, the larger the width of the discharge port, the better the material passability (easier to pass through the discharge port, less likely to form an arch), and the greater the material flow rate. However, for some metal mines with large bulk densities, in order to prevent the belt conveyor from overloading, the material flow must be controlled and the width of the discharge port B1 must be reduced, which reduces the material passability, resulting in poor material discharge and even blocking, affecting production efficiency.

[0051] In this process, it is not difficult to find that since the material passability and material flow controllability are related to the discharge port width B1 at the same time, it is difficult to meet their operating conditions at the same time, resulting in mutual influence and interference, which leads to unstable material flow control and difficulty in coordination.

[0052] Ideas for stable material flow control

[0053] Practice has proved that there are two main ideas: one is step-by-step control (first let the material pass, then control the material flow); the other is to change from controlling the width of the discharge port to controlling the height of the material layer (such as Figure 3 , Figure 4 In the middle, the height of the secondary discharge port is h).

[0054] The principle of step-by-step control is: the first step is to widen the discharge port (generally less than two-thirds of the belt width) to ensure the passability, so that the material reaches the belt and passes through the first-level discharge port; the second step is to realize material flow control to meet the requirement of not overloading the belt conveyor.

[0055] The control of the discharge port width is changed to the control of the material layer height; as the discharge port width increases, the height also increases (as mentioned above), the material can pass through the discharge port relatively smoothly and reach the buffer zone outside the hopper. At this time, the material flow is overloaded, and then the secondary discharge port height (i.e. the material layer thickness) is adjusted through the set secondary discharge port. Figure 3 In the process, the secondary discharge port height h) is reduced to reduce part of the material remaining in the buffer zone, thereby achieving stable material flow control. In actual application, the material reaching the belt conveyor is very uniform and stable.

[0056] The present invention can remove the complicated opening and closing mechanism of the existing bulk hopper, extend the side plates on both sides of the hopper mouth, and form a buffer zone that is closed in the circumference and open in the upper and lower directions in front of the raw material hopper body 1. The buffer zone has two functions: one is to store a small amount of material to be cut for a short time, and the other is to facilitate the observation of foreign matter and remove it from the open area above the buffer zone (requiring a short shutdown operation).

[0057] The width B1 of the secondary discharge port 4 should be less than two-thirds of the belt width to prevent side overflow. Figure 4 A movable adjustment plate that can be adjusted up and down is set at the secondary discharge port, and the height h of the secondary discharge port is adjusted to control the material layer thickness, thereby realizing material flow control.

[0058] Specific working principle: When larger foreign matter (assuming the particle size is A1) is mixed in the material, when A1 moves to the belt near the primary discharge port, since A1 is less than H (the height of the primary discharge port), under the action of the belt friction, the foreign matter can enter the buffer zone through the primary discharge port. Since A1 is greater than h (the height of the secondary discharge port), the foreign matter cannot pass through the secondary discharge port and stays in the buffer zone. As the material moves forward under the action of the belt friction, the material is squeezed and the foreign matter will jump in the buffer zone (at this time, the foreign matter has no other external pressure except its own weight (the weight of the small amount of material cut can be ignored) and will not be inserted into the belt). Other materials with a particle size smaller than h can still pass through the secondary discharge port (at this time, the material flow rate will be slightly reduced, and in practice it will not be completely blocked, and the foreign matter will continue to jump). If the operator nearby observes that there is a foreign matter jumping, the machine can be stopped for a short time, and the foreign matter can be easily removed from the top of the buffer zone to resume production, thereby avoiding the long-distance tearing of the belt due to the obstruction of foreign matter.

[0059] In actual application, for the convenience of operation, a corresponding reference table of material bulk density and secondary discharge port height is listed according to the bulk density of the material, which has achieved good results. Figure 6 , Table 1, Correspondence between material bulk density and secondary discharge port height,

[0060] After statistics of practical application data, theoretical derivation and practical application correction, the relationship between material bulk density, belt running speed, maximum design flow rate of belt conveyor and discharge port height is summarized as follows:

[0061] P=(972*h+1440)*h*v*γ

[0062] In the formula,

[0063] P---The maximum design flow rate of the belt conveyor, unit: tons / hour (t / h). For example, if the maximum design material flow rate of the belt conveyor in use is 1500t / h, the belt width is 1.2 meters, and the set discharge port width is 0.4 meters.

[0064] h---height of secondary discharge port, unit: meter (m)

[0065] v---belt running speed, unit: meter / second (m / s), the belt conveyor speed in use is 3.15m / s

[0066] γ---Material bulk density, unit: tons / cubic meter (t / m 3 )

[0067] Table 1 Correspondence between material bulk density and secondary discharge port height

[0068]

[0069] Note: In actual production, under extreme circumstances, there are occasionally foreign objects with a particle size larger than the height H of the first-level discharge port. To this end, an isolation net with a single hole size of H*H is added at the feed port of the bulk hopper, so that foreign objects with a particle size larger than the height H of the first-level discharge port are intercepted on the isolation net and will not enter the hopper.

Claims

1. A bulk cargo hopper for preventing longitudinal tearing of a belt, comprising a hopper body, wherein the hopper body has a feed inlet located at the top and a discharge outlet located at the bottom, characterized in that: A primary discharge port is opened on the side of the hopper body from the bottom upward; a buffer zone connected to the primary discharge port is arranged outside the primary discharge port of the hopper body, and the buffer zone is a cavity which is closed circumferentially and open at the top and bottom; a secondary discharge port is arranged at the front end of the buffer zone.

2. The bulk cargo hopper for preventing longitudinal tearing of belts according to claim 1, characterized in that: The secondary discharge port is provided with a secondary discharge port adjusting plate, and the secondary discharge port adjusting plate is used to adjust the height of the secondary discharge port.

3. The bulk cargo hopper for preventing longitudinal tearing of belts according to claim 2, characterized in that: The buffer zone comprises two buffer zone side panels, and the two buffer zone side panels are coplanar with the hopper body side panels.

4. The bulk cargo hopper for preventing longitudinal tearing of belts according to claim 3, characterized in that: The height of the buffer zone side panel is higher than the height of the primary discharge port.

5. The bulk cargo hopper for preventing longitudinal tearing of belts according to claim 4, characterized in that: The buffer zone also includes a buffer zone front panel, and the secondary discharge port is located on the buffer zone front panel; the buffer zone front panel, two buffer zone side panels and the hopper body front side panel enclose the buffer zone.

6. The bulk cargo hopper for preventing longitudinal tearing of belts according to claim 5, characterized in that: A height adjustment hole is arranged on the front panel of the buffer zone along the height direction, and the secondary discharge port adjustment plate is adjusted to an upper and lower position on the front panel of the buffer zone through the height adjustment hole.

7. The bulk cargo hopper for preventing longitudinal tearing of belts according to any one of claims 1 to 6, characterized in that: The buffer zone is integrated with the hopper body.

8. The bulk cargo hopper for preventing longitudinal tearing of belts according to any one of claims 1 to 6, characterized in that: The width of the secondary discharge port is less than two-thirds of the belt width.

9. A material flow control method for a bulk cargo hopper with an anti-belt longitudinal tearing function according to any one of claims 1 to 8, characterized in that: The height of the secondary discharge port is calculated based on the bulk density of the material, and the material flow rate is controlled by the height of the secondary discharge port.

10. The material flow control method according to claim 9, characterized in that: According to the bulk density of the material, the running speed of the belt, the maximum design flow rate of the belt conveyor and the practical correction value, the expression of the secondary discharge port height is obtained as follows: h=P / (972*h+1440)*v*γ In the formula, h is the height of the secondary discharge port; P is the maximum design flow rate of the belt conveyor; γ is the belt running speed; γ is the bulk density of the material.

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