Flaring inward-extending pipe with top center inserted type anti-fatigue structure for separating materials

Abstract

The utility model discloses a top center insertion type anti-fatigue structure flaring inward extending pipe for separating materials, and belongs to the field of separation equipment in the petrochemical industry. The flaring inner extending pipe comprises a feeding pipe, a central pipe and a spraying pipe which are sequentially connected and coaxially arranged; the feeding pipe is connected with the central pipe through a threaded structure, and a gap straight section is arranged at each of the connecting parts of the two pipes at the upstream and the downstream of the threaded structure; the central pipe comprises a spiral groove section and an equal-diameter straight section which are sequentially connected in the flowing direction, the inner diameter of the spiral groove section is gradually increased in the flowing direction, and a spiral groove is formed in the inner wall of the spiral groove section; the thread direction of the spiral groove is opposite to that of the thread structure; the inner diameter of the spray pipe is gradually increased in the flowing direction. According to the flaring inward-extending pipe, vibration of the flaring inward-extending pipe in the working process can be reduced, and fatigue damage and damage of a threaded connection structure are reduced.

Description

Technical Field

[0001] The utility model belongs to the field of separation devices, and particularly relates to a top-center inserted anti-fatigue structure flared inner extension pipe for separating materials. Background Art

[0002] In petrochemical plants, the need to separate different media often arises. In polymerization reaction devices for polymer materials, in order to separate different-phase media (generally reaction products and unreacted phases), the principle of gravity separation is often adopted, and separation is achieved by utilizing the density difference of the media.

[0003] For some high-viscosity non-crystalline polymer materials, sometimes two-phase flow is used to entrain the polymer material and quickly eject it from the nozzle of the flared structure. After the high-viscosity polymer material is ejected, it generally adheres to the container wall, while the gas phase will escape. The medium entrained by the escaping gas phase is separated by gravity, and the separation of different-phase media is achieved through the above two processes.

[0004] In current industry, for large processing volumes and high material viscosities, gravity separators (equipment) are mainly used to achieve gas-liquid separation. Generally, a simple inner extension pipe is arranged inside the gravity separator (equipment) as the feeding and spraying device for the material to be separated. The outlet end of the inner extension pipe often adopts a flared structure in the shape of a horn. However, the flared structure in the shape of a horn often has severe vibrations, resulting in damage to the center pipe structure of the flared opening, especially the middle connection part, causing frequent shutdowns for replacement and repair. Summary of the Utility Model

[0005] To solve the problems in the prior art, the utility model proposes a top-center inserted anti-fatigue structure flared inner extension pipe for separating materials.

[0006] The utility model first proposes a top-center inserted anti-fatigue structure flared inner extension pipe for separating materials, which sequentially connects and coaxially arranges a feeding pipe, a center pipe, and a spraying pipe; the feeding pipe and the center pipe are connected by a threaded structure, and a section of gap straight section is arranged at the connection parts of the two pipes upstream and downstream of the threaded structure; the center pipe and the spraying pipe are fixedly connected or integrally formed; the center pipe includes a spiral groove section and an equal-diameter straight section that are sequentially connected along the flow direction, wherein the inner diameter of the spiral groove section gradually increases along the flow direction, and the inner wall is provided with spiral grooves; the spiral grooves are opposite to the thread direction of the threaded structure; the tail end of the feeding pipe is provided with an enlarged-diameter flared opening, and the outlet end of the enlarged-diameter flared opening is connected to the spiral groove section; the inner diameter of the spraying pipe gradually increases along the flow direction.

[0007] According to a preferred embodiment of the present utility model, a flange structure is connected to the outer wall surface of the feed pipe; the flange structure is used to install the flared inner extension pipe vertically downward to the top of the gas-liquid separator, and the axis of the flared inner extension pipe coincides with the central axis of the gas-liquid separator.

[0008] According to a preferred embodiment of the present utility model, a split hoop is provided at the connection of the outer wall surface of the feed pipe and the central pipe, and the split hoop is used to lock the feed pipe and the central pipe to prevent the loosening of the threaded structure.

[0009] According to a preferred embodiment of the present utility model, at the clearance straight section, the feed pipe is sleeved inside the central pipe, and the two are in clearance fit. 1 to 3 positioning pins are circumferentially arranged at the clearance straight section downstream of the threaded structure for realizing the centering and locking of the feed pipe and the central pipe.

[0010] The present utility model also provides a gas-liquid separator having the flared inner extension pipe. The gas-liquid separator is a kettle-type separator. The flared inner extension pipe is installed vertically downward at the top of the gas-liquid separator, and the axis of the flared inner extension pipe coincides with the central axis of the gas-liquid separator; the distance from the outlet of the flared inner extension pipe to the bottom of the gas-liquid separator is 1 / 4 to 1 / 2 of the height of the gas-liquid separator.

[0011] Compared with the prior art, the present utility model has the following advantages:

[0012] 1) The flared inner extension pipe of the present utility model adopts a structure with a gradually increasing inner diameter from top to bottom. Among them, the tail end of the feed pipe, the spiral groove section, and the nozzle are all flared designs. According to the Bernoulli principle of fluid mechanics, the pressure of the two-phase fluid gradually decreases during the process of flowing out from top to bottom, and the static pressure head is converted into the dynamic pressure head, resulting in an increase in the fluid velocity. Finally, the two-phase flow "sprays" out from the bottom of the horn-shaped central pipe at the bottom. The amorphous polymer material in the two-phase flow will adhere to the material piled up at the bottom of the separation container due to its relatively high viscosity, while the gas phase will be reflected and dissipated accordingly.

[0013] 2) The feed pipe and the central pipe of the present utility model are connected by a threaded structure, and the spiral groove has the opposite thread direction to the threaded structure of the threaded structure. The load-bearing capacity of the thread is relatively strong, but the flow path of the central feed pipe changes continuously from top to bottom, the density of the two-phase flow is uneven, and phase change may also occur during the flow process. All these reasons lead to the existence of additional circumferential bending loads while there is an axial load on the central feed pipe, resulting in fatigue failure. In order to reduce the additional bending load and fatigue damage, a spiral groove is provided in the spiral groove section to guide the medium to rotate circumferentially, and the spiral groove with a longer and larger flow path is used to slow down the circumferential force. The spiral groove will cause an additional axial torque. The threaded connection structure and the spiral groove processed in the flow path are set in the opposite direction to avoid the thread loosening and fatigue damage caused by the additional torque.

[0014] 3) In the present utility model, a section of clearance straight section is provided at both the upstream and downstream pipe connection parts of the threaded structure. The clearance straight section enables good contact between the feed pipe and the central pipe, and tries to avoid the transfer of the additional bending moment load at the bottom to the threaded structure, playing a role in protecting the threaded structure. A split hoop is provided at the connection between the outer wall surface of the feed pipe and the central pipe in the present utility model. The split hoop is used to lock the feed pipe and the central pipe, prevent the threaded structure from loosening, realize the rigid transition of the two parts, and slow down the local stress concentration and fatigue damage. Brief Description of the Drawings

[0015] Figure 1 It is a schematic structural view of the flared inner extending pipe of the present utility model;

[0016] Figure 2 It is a schematic installation view of the flared inner extending pipe in the gas-liquid separator;

[0017] Figure 3 It is a schematic installation view of the threaded structure and the clearance straight section;

[0018] Figure 4 It is a schematic installation view of the split hoop and the positioning pin;

[0019] Figure 5 It is a schematic flange structure view;

[0020] Figure 6 It is a schematic view of the spiral groove;

[0021] In the figure: flange structure 1, feed pipe 2, stress relief groove 3, spiral groove 4, nozzle 5, equal-diameter straight section 6, positioning pin 7, split hoop 8, clearance straight section 9. Detailed Embodiment

[0022] The following further elaborates and explains the present utility model in combination with the specific embodiments. The described embodiments are only demonstrations of the present disclosure content and do not delimit the scope of limitation. The technical features of each embodiment in the present utility model can be combined correspondingly without conflict.

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present utility model with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present utility model without creative efforts belong to the scope protected by the present utility model.

[0024] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present utility model are only used to explain the relative positional relationship and movement conditions between components in a certain specific posture (as shown in the attached drawings). If this specific posture changes, the directional indications will also change accordingly.

[0025] In the present utility model, unless otherwise clearly defined and limited, terms such as "connection" and "fixation" shall be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection, an electrical connection, or a physical connection; it can be directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two components or the interaction relationship between two components, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0026] As Figure 1 shown, the top-center-inserted anti-fatigue structure flared inner extension pipe for separating materials includes, from top to bottom, a feed pipe 2, a central pipe, and a spray pipe 5 that are sequentially connected and coaxially arranged. Among them, the feed pipe 2 and the central pipe in this embodiment are connected by a threaded structure, and a section of clearance straight section 9 is provided at both the upstream and downstream connection parts of the threaded structure. The central pipe includes a spiral groove section 4 and an equal-diameter straight section 6 that are sequentially connected along the flow direction. The inner diameter of the spiral groove section 4 increases gradually along the flow direction, and the inner wall is provided with a spiral groove 4; the spiral groove 4 has a thread direction opposite to that of the threaded structure; the tail end of the feed pipe 2 is provided with an enlarged-diameter bell mouth, and the outlet end of the enlarged-diameter bell mouth is connected to the spiral groove section 4; the spray pipe 5 has an inner diameter that gradually increases along the flow direction, that is, it is in the shape of a bell mouth, and the spraying angle of the bell mouth is 10-45°, which is comprehensively determined according to the tank diameter and the insertion length of the inner extension pipe. At the clearance straight section, the feed pipe is sleeved inside the central pipe, and the two are in clearance fit.

[0027] The internal flow path of the flared inner extension pipe shown in the embodiment is a structure with an inner diameter that gradually increases from top to bottom. According to the Bernoulli principle of fluid mechanics, during the process of the two-phase fluid flowing out from top to bottom, the pressure gradually decreases, and the static pressure head is converted into dynamic pressure head, resulting in an increase in the fluid velocity. Finally, the two-phase flow "sprays" out from the bottom of the bottom bell-shaped central pipe. The amorphous polymer material in the two-phase flow will adhere to the logistics accumulated at the bottom of the separation container due to its relatively high viscosity, while the gas phase will be reflected and dissipated accordingly.

[0028] The central pipe and the nozzle 5 can be fixedly connected or integrally formed. The gas phase reflected and dissipated at the lower part of the separation container slowly flows upward. The unreacted gas phase still entrained a small amount of amorphous polymer materials in particulate form. Under the action of gravity, separation will occur. Since gravity is constant, the separation effect at this time directly depends on the gas velocity and the travel length of the gas flowing out of the reactor. Therefore, the penetration length of the central pipe needs to be long enough if possible. The present utility model is provided with an equal-diameter section 6 for maintaining and adjusting the overall length of the central pipe and the inner extension pipe, guiding the gas flow downward so that the gas flow comes out from the bottom of the gas-liquid separator as much as possible. Among them, the length-diameter ratio of the central pipe should be greater than 20, preferably 30-50. The distance from the outlet of the flared inner extension pipe to the bottom of the gas-liquid separator is 1 / 4 to 1 / 2 of the height of the gas-liquid separator.

[0029] Since the overall length of the flared inner extension pipe is relatively long and it is difficult to process integrally, therefore, in this embodiment, a segmented design is adopted. It is obviously a better choice to process in segments and then assemble them. Among them, the feed pipe and the central pipe are connected by a threaded structure. Under the action of a unidirectional tensile load, the threaded structure has a strong load-bearing capacity. However, the flow channel of the inner extension pipe changes continuously from top to bottom, the density of the two-phase flow is uneven, and phase change may also occur during the flow process. All these reasons result in the existence of an additional circumferential bending load on the central feed pipe while there is an axial load.

[0030] In order to reduce the additional bending load, a spiral groove 4 is machined at the flared flow channel part of the central pipe to guide the medium to rotate circumferentially. The spiral groove 4 with an extended and enlarged flow channel can also slow down the circumferential force (see details in Figure 6 ). The spiral groove 4 will cause an additional axial torque. Therefore, the connecting thread of the segmented central pipe and the spiral groove 4 machined in the flow channel are set in the opposite direction to avoid the loosening of the thread due to the additional torque.

[0031] Considering that the threaded connection structure of the upper and lower segments of the inner extension pipe will be damaged due to the influence of the additional bending moment, especially prone to fatigue damage. In order to avoid damage to the thread, the present utility model adopts the following measures:

[0032] 1) A section of clearance straight section 9 is provided at the lower part of the thread of the threaded structure. In this embodiment, it is called the thread protection device (lower part) (see details in Figure 3 ). The upper and lower segments of the inner extension pipe (referring to the central pipe and the feed pipe 2) achieve good contact in this section, and try to avoid the transfer of the bottom additional bending moment load to the upper threaded structure.

[0033] 2) A section of clearance straight section 9 is also provided at the upper part of the thread of the threaded structure. In this embodiment, it is called the thread protection device (upper part) (see details in Figure 3 ). The central pipe and the feed pipe 2 achieve good contact in this section, and try to avoid the transfer of the bottom additional bending moment load to the upper threaded structure.

[0034] 3) The small gap straight section 9 at the bottom of the threaded connection structure is circumferentially provided with 1 to 3 positioning pins 7 for locking (see Figure 4 ), which can realize the centering of the inner and outer tubes and assist in the centering and fixing of the inner and outer tubes.

[0035] 4) A petal clamp 8 is arranged outside the upper and lower segmented threaded connection structure (see Figure 4 ), the function of the clamp is to prevent the thread from loosening, achieve a rigid transition between the two parts, and alleviate local stress concentration.

[0036] 5) In order to achieve rigidity matching, an annular stress relief groove 3 is provided at the position where the feed pipe 2 passes through the center of the flange structure 1 (see Figure 5 ). Since the rigidity difference between the feed pipe 2 and the flange structure 1 is too large, it is impossible to avoid the formation of a large stress concentration in the attachment area under the action of the attachment bending moment. By providing an annular stress relief groove 3 at the end of the flange structure 1, the local rigidity is reduced, thereby reducing the stress in the feed pipe 2, especially the fatigue life.

[0037] like Figure 2 As shown, this embodiment provides a gas-liquid separator with the flared inner extension pipe, the gas-liquid separator is a kettle separator, the flared inner extension pipe is installed on the top of the gas-liquid separator in a vertical downward manner, and the axial direction of the flared inner extension pipe coincides with the central axis of the gas-liquid separator; the distance from the outlet of the flared inner extension pipe to the bottom of the gas-liquid separator is 1 / 4 to 1 / 2 of the height of the gas-liquid separator. The flared inner extension pipe design of this embodiment can reduce the problem of easy damage to the connection part caused by the vibration of the flared structure. Due to the characteristics of the process medium of some petrochemical devices, when performing logistics separation, the material can be fed from the bottom, the side wall, or the top. This embodiment considers the use of impact entrainment, adhesion, and gravity separation principles, so it is selected to feed from the top. When feeding at the top, due to the two-phase flow, it is inevitable that additional circumferential bending and vibration will occur. The process hole opened in the center can try to ensure uniform circumferential load. Therefore, a feed pipe is set in the center.

[0038] The above-mentioned embodiments only express several implementation methods of the utility model, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the utility model. For ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the utility model, which all belong to the protection scope of the utility model.

Claims

1. A top center inserted anti-fatigue structure expanded inner extension tube for separating materials, characterized in that include: A feed pipe, a center pipe and a nozzle are connected in sequence and arranged coaxially; The feed pipe and the center pipe are connected by a threaded structure, and a gap straight section is provided at the connection parts of the two pipes upstream and downstream of the threaded structure; the center pipe and the nozzle are fixedly connected or integrally formed; The central tube comprises a spiral groove section and a straight section of equal diameter connected in sequence along the flow direction, wherein the inner diameter of the spiral groove section increases gradually along the flow direction, and the inner wall is provided with a spiral groove; the spiral groove is opposite to the thread direction of the thread structure; The tail end of the feed pipe is provided with an expanded diameter bell mouth, and the outlet end of the expanded diameter bell mouth is connected to the spiral groove section; the inner diameter of the nozzle gradually increases along the flow direction.

2. The flared inner extension tube according to claim 1, characterized in that: The outer wall surface of the feed pipe is connected with a flange structure; the flange structure is used to install the expanded inner extension pipe to the top of the gas-liquid separator in a vertical downward manner, and the axial direction of the expanded inner extension pipe coincides with the central axis of the gas-liquid separator.

3. The flared inner extension tube according to claim 2, characterized in that: The top of the flange structure is provided with a threaded mounting hole; the bottom is provided with a circle of annular stress release grooves.

4. The flared inner extension tube according to claim 1, characterized in that: The outer wall surface of the feed pipe is provided with a petal clamp at the connection with the central pipe, and the petal clamp is used to lock the feed pipe and the central pipe to prevent the thread structure from loosening.

5. The flared inner extension tube according to claim 1, characterized in that: At the straight section of the gap, the feed pipe is sleeved in the center pipe, and the two are clearance-matched.

6. The flared inner extension tube according to claim 5, characterized in that: One to three positioning pins are circumferentially arranged on the gap straight section downstream of the thread structure to realize centering and locking of the feed pipe and the center pipe.

7. The flared inner extension tube according to claim 1, characterized in that: The length-to-diameter ratio of the central tube is greater than 20.

8. The flared inner extension tube according to claim 7, characterized in that: The length-to-diameter ratio of the central tube is 30-50.

9. The flared inner extension tube according to claim 1, characterized in that: The inner diameter of the expanded bell mouth outlet end matches the inner diameter of the spiral groove section inlet section.

10. A gas-liquid separator having the expanded inner extension tube according to any one of claims 1 to 9, characterized in that: The gas-liquid separator is a kettle-type separator, the flared inner extension tube is installed on the top of the gas-liquid separator in a vertical downward manner, and the axial direction of the flared inner extension tube coincides with the central axis of the gas-liquid separator; the distance from the outlet of the flared inner extension tube to the bottom of the gas-liquid separator is 1 / 4 to 1 / 2 of the height of the gas-liquid separator.

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