Three-screw pump unit and material conveying system having the same unit

Abstract

This utility model relates to the field of material handling equipment technology, and more specifically to a three-screw pump device capable of pressure protection, and a material conveying system having the device. The three-screw pump device includes a housing, within which are formed: a feed chamber connected to an inlet, a discharge chamber connected to an outlet, and a conveying channel connecting the feed chamber and the discharge chamber; the conveying channel houses: a rotatable driving screw and two rotatable driven screws, the two driven screws being respectively located on both sides of the driving screw and both screwed to the driving screw; the driving screw is driven by a drive device that provides rotational force to it; the discharge chamber is also connected to: a pressure relief channel for discharging material from the discharge chamber to the external space; a pressure relief valve is provided in the pressure relief channel, configured to: control the pressure relief channel to be in a free-flowing discharge state / a blocked closed state when the hydraulic pressure in the discharge chamber is greater than / not greater than a predetermined value.

Description

Technical Field

[0001] This utility model relates to the field of material transport equipment technology, and more specifically to a three-screw pump device capable of pressure protection, and a material conveying system having the device. Background Technology

[0002] The three-screw pump, a typical rotary positive displacement pump, has a core working unit consisting of a screw pair comprising one driving screw and two driven screws, which, together with the pump body's internal cavity wall, form the pump. By setting appropriate gaps between the screw pairs and between the screws and the pump body's internal cavity wall, the pump utilizes the volume change of the sealed chamber formed by the meshing of the three screws as they rotate, achieving continuous and uniform liquid delivery along the screw axis. The liquid is then stably delivered to the dosing point through the outlet. This structural design gives it technical advantages such as stable flow rate, low pressure pulsation, and strong pressure resistance, making it widely used in the transportation of industrial fluids such as lubricating oil, coolant, hydraulic oil, and fuel oil.

[0003] However, in practical engineering applications, it has been found that three-screw pumps are prone to failure during long-term use, which can lead to unexpected equipment shutdowns or even damage to related components, making it difficult to effectively guarantee their operational stability and reliability. Utility Model Content

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a three-screw pump device with a pressure relief protection structure, which can improve operational stability and reliability.

[0005] The overall technical solution of this utility model is as follows:

[0006] This invention addresses the problem of low operational stability and reliability of existing three-screw pumps. Specifically, due to its three-screw configuration, the three-screw pump can consistently transport materials at a large flow rate. However, in actual production environments, due to diverse factors such as media characteristics (e.g., viscosity fluctuations, impurity content) and operating conditions (e.g., pressure shocks, temperature changes), the discharge port of the three-screw pump is prone to blockage or accidental closure. This leads to a sharp increase in internal pressure, which can easily cause malfunctions, resulting in unexpected equipment shutdowns or even damage to related components. Consequently, the operational stability and reliability of the three-screw pump cannot be effectively guaranteed.

[0007] Based on this, the present invention provides a three-screw pump device that improves operational stability and reliability by setting a pressure relief protection structure.

[0008] Specifically, the three-screw pump device of this utility model includes a housing, which has the following internally formed: a feed chamber connected to a feed inlet, a discharge chamber connected to a discharge outlet, and a conveying channel connecting the feed chamber and the discharge chamber.

[0009] The material conveying channel contains: a rotatable driving screw and two rotatable driven screws, with the two driven screws respectively located on both sides of the driving screw and both screwed to the driving screw;

[0010] The active screw drive is connected to a drive device that provides rotational force to it. By driving the active screw to rotate, it drives the two driven screws to rotate synchronously, so as to transport the material in the feed chamber to the discharge chamber.

[0011] The discharge chamber is also connected to a pressure relief channel for discharging the material in the discharge chamber to the external space;

[0012] The pressure relief channel is equipped with a pressure relief valve, which is configured to control the pressure relief channel to be in a free-flowing discharge state or a blocked closed state when the hydraulic pressure in the discharge chamber is greater than or not greater than a limit value.

[0013] The pressure relief channel and pressure relief valve together form a pressure relief protection structure. When the three-screw pump is operating normally and the pressure inside the discharge chamber is less than the limit value, the pressure relief valve closes to control the pressure relief channel to be in a blocked closed state, preventing material from flowing out of the pressure relief channel and ensuring that the three-screw pump can stably deliver materials in a directional manner. When the hydraulic pressure in the discharge chamber rises unexpectedly and sharply, indicating a need for pressure relief (often due to accidental blockage of the discharge port), the pressure relief valve opens to control the pressure relief channel to be in a smooth drainage state, allowing the material in the discharge chamber to be discharged outward through the pressure relief channel, reducing the internal pressure of the discharge chamber, and thus better avoiding malfunctions and damage caused by excessive internal pressure of the three-screw pump, thereby improving the overall operational stability and reliability of the three-screw pump.

[0014] The pressure relief channel can be located on any side wall of the discharge chamber and connected to the discharge chamber.

[0015] However, when the outlet of the pressure relief channel is opposite to the outlet of the material conveying channel, the material output from the material conveying channel is prone to exert an excessive instantaneous impact on the pressure relief valve, causing the pressure relief valve to be accidentally affected when there is no pressure relief requirement. This results in the pressure relief channel being unobstructed for a short period of time, affecting the stability and effectiveness of material transportation under normal operating conditions of the three-screw pump unit.

[0016] Therefore, as a preferred embodiment, in some implementations, one end of the pressure relief channel is a pressure relief port communicating with the discharge chamber, and the other end is a pressure discharge port for discharging the material in the pressure relief channel outward.

[0017] Furthermore, the pressure relief port is located on the first side wall of the discharge chamber;

[0018] One end of the material conveying channel is connected to the discharge chamber and is located on the second side wall of the discharge chamber;

[0019] The first and second sidewalls are arranged in a non-aligned manner.

[0020] By arranging the pressure relief port and the discharge port of the conveying channel in a non-aligned manner, the material output from the conveying channel will not directly impact the pressure relief port and pressure relief valve, thereby reducing the possibility of the pressure relief valve being accidentally opened or closed during normal material transportation, and further improving the operational stability and reliability of the three-screw pump unit with pressure relief protection structure.

[0021] At this point, based solely on the need for pressure relief, although the pressure relief port can be located on either the upper or lower side wall of the discharge chamber, actual use has revealed that: when the pressure relief port is located on the upper side wall of the discharge chamber, the material needs to overcome its own gravity to flow upwards, increasing the difficulty of pressure relief and making it impossible to quickly and effectively relieve pressure, thus compromising the effectiveness and timeliness of pressure relief; while when the pressure relief port is located on the lower side wall of the discharge chamber, the gravity of the material will always exert a certain pressure on the pressure relief valve, causing the valve to be under considerable pressure even when there is no need for pressure relief, which can negatively impact the service life of the valve.

[0022] Therefore, as a further preferred embodiment, in some implementations, the pressure relief channel is configured to extend in the horizontal direction;

[0023] Furthermore, the pressure relief port is located on any side wall of the discharge chamber in the horizontal direction (i.e., on any side wall of the discharge chamber, either the front side wall, the rear side wall, the left side wall, or the right side wall).

[0024] By placing the pressure relief port on any side wall in the horizontal direction of the discharge chamber, the effectiveness and timeliness of pressure relief can be better ensured, while also reducing the adverse effects of material gravity on the pressure relief protection structure.

[0025] For specific pressure relief valves.

[0026] In some embodiments, in the direction from the pressure relief port to the pressure discharge port, the pressure relief channel sequentially includes: a first flow channel section communicating with the pressure relief port, and a second flow channel section communicating with the pressure discharge port;

[0027] One end of the first flow channel section is connected to the second flow channel section, and the channel diameter of the second flow channel section is larger than that of the first flow channel section.

[0028] Pressure relief valve components include:

[0029] A sealing element that is installed in the second flow channel section and can seal one end of the first flow channel section forms a gap between itself and the channel wall of the second flow channel section to allow material flow.

[0030] A resilient pressure limiting member is configured to apply an elastic force, either in a tensile or compressive manner, to the sealing member, thereby causing the sealing member to seal one end of the first flow channel section.

[0031] In some embodiments, a locking member is fixed in the second flow channel section, located on the side of the sealing member facing away from the first flow channel section;

[0032] The pressure limiting element is compressed and positioned between the sealing element and the locking element to apply an elastic force to the sealing element;

[0033] Furthermore, the middle part of the locking component is provided with a material passage for material flowing from the pressure relief port to the pressure discharge port to pass through the locking component.

[0034] Alternatively, in some embodiments, a locking member is fixed in the second flow channel section, located on the side of the sealing member facing away from the first flow channel section;

[0035] The pressure limiting element is compressed and positioned between the sealing element and the locking element to apply an elastic force to the sealing element;

[0036] Furthermore, the outer edge of the locking component is provided with a slot, and a channel is formed between the slot and the pipe wall of the second flow channel section at intervals, allowing material flowing from the pressure relief port to the pressure discharge port to pass through the locking component.

[0037] By setting up a locking component, a more stable support is provided for the pressure limiting component, enabling the pressure limiting component to provide the required elastic force to the sealing component more stably. This allows the sealing component to stably seal the first flow channel section during normal operation of the three-screw pump unit, thus better ensuring the stability of material transportation during normal operation of the three-screw pump unit.

[0038] Furthermore, in some embodiments, the second flow channel section is a channel that extends in a straight line;

[0039] The locking member is detachably fixed in the second flow channel section, and the pressure relief port is formed at the end of the second flow channel section, providing an opening for the locking member to enter and exit the second flow channel section.

[0040] By making the locking components detachable, it is easier to maintain the three-screw pump unit with pressure relief protection structure (it is also easier to disassemble and maintain the locking components with material flow channels that are prone to blockage, and it is also easier to clean the pressure relief channels), so as to better extend the service life of the three-screw pump unit.

[0041] In some embodiments, the side of the plugging member facing the first flow channel section has a protruding guide portion;

[0042] The guide portion is adapted to the first flow channel section and is configured to: when the sealing member seals one end of the first flow channel section, it is adapted to be inserted into one end of the first flow channel section;

[0043] Furthermore, the outer surface of the guide portion is inclined and has a guide surface that guides the guide portion to be inserted into the first flow channel section.

[0044] By setting a guide insert with a guide surface, the positioning stability of the sealing component during normal operation of the three-screw pump is further improved, so that the sealing component can more stably seal the first flow channel section during normal operation of the three-screw pump, and better ensure the stability of material transportation during normal operation of the three-screw pump.

[0045] This invention further provides a material conveying system having the three-screw pump device described in any of the above embodiments.

[0046] In some embodiments, the material conveying system further includes:

[0047] A material box, which has a material cavity for containing materials;

[0048] The feed pipe has: one end connected to the feed port of the three-screw pump device, and the other end connected to the material chamber, so as to guide the material in the material chamber to the inlet channel in the feed port;

[0049] The return pipe has: one end connected to the pressure relief channel of the three-screw pump device, and the other end connected to the material chamber, so that the material that has been depressurized to the pressure relief channel can return to the return channel in the material chamber.

[0050] By setting up the feed pipe and return pipe, the material box and the three-screw pump unit form a material depressurization and return system, so that the material discharged after depressurization can still flow back into the material box for reuse, avoiding material waste.

[0051] The main beneficial effects of the above technical solution are as follows:

[0052] 1. The pressure relief channel and pressure relief valve together form a pressure relief protection structure. When the hydraulic pressure in the discharge chamber rises unexpectedly and rapidly, the material in the discharge chamber can be discharged outward through the pressure relief channel, reducing the internal pressure of the discharge chamber. This better avoids malfunctions and damage caused by excessive internal pressure of the three-screw pump, thereby improving the overall operational stability and reliability of the three-screw pump unit.

[0053] 2. By arranging the pressure relief port and the discharge port of the material conveying channel in a non-aligned manner, the possibility of the pressure relief valve being accidentally opened or closed during normal material transportation can be reduced, thereby further improving the operational stability and reliability of the three-screw pump unit with pressure relief protection structure.

[0054] 3. By setting the pressure relief port on any side wall in the horizontal direction of the discharge chamber, the effectiveness and timeliness of pressure relief can be better guaranteed, while also reducing the adverse effects of material gravity on the pressure relief protection structure.

[0055] 4. By setting up a locking component, the pressure limiting component can be better supported, enabling it to provide the necessary elastic force to the sealing component more stably, thereby better ensuring the stability of material transportation during normal operation of the three-screw pump unit.

[0056] 5. By making the locking components detachable, it is easier to maintain the three-screw pump unit with pressure relief protection structure, so as to better extend the service life of the three-screw pump unit.

[0057] 6. By setting a guide insert with a guide surface, the positioning stability of the sealing component during normal operation of the three-screw pump is further improved, so that the sealing component can more stably seal the first flow channel section during normal operation of the three-screw pump, and better ensure the stability of material transportation during normal operation of the three-screw pump.

[0058] 7. By setting up the feed pipe and return pipe, the material box and the three-screw pump unit form a pressure relief and return system, so that the material discharged after pressure relief can still flow back into the material box for reuse, avoiding material waste.

[0059] Further or more detailed beneficial effects will be described in conjunction with specific embodiments in the detailed implementation. Attached Figure Description

[0060] The present invention will be further described below with reference to the accompanying drawings:

[0061] Figure 1 This is a front sectional view of a three-screw pump unit.

[0062] Figure 2 A schematic diagram of a pressure relief protection structure consisting of a pressure relief channel and pressure relief valve.

[0063] Figure 3 This is a side sectional view of a three-screw pump unit.

[0064] Figure 4 This is a schematic diagram of the normal operation of a material conveying system.

[0065] Figure 5 A schematic diagram of a material conveying system during depressurization. Detailed Implementation

[0066] The present invention will be illustrated with specific examples below: Example 1:

[0067] Three-screw pump unit, as attached Figure 1 To be continued Figure 3 As shown, it includes a housing 1, on which a connecting part 1.1 is provided for connection with an external support structure or platform structure, so that the three-screw pump device can be connected as shown in the attached diagram. Figure 4 To be continued Figure 5 The installation and layout will be carried out in the middle.

[0068] Among them, as attached Figure 1 As shown, the interior of the housing 1 is hollow and has: a feeding chamber 1.2 connected to a feeding port 1.21, a discharging chamber 1.3 connected to a discharging port 1.31, and a conveying channel 1.4 connecting the feeding chamber 1.2 and the discharging chamber 1.3.

[0069] Furthermore, the material conveying channel 1.4 houses a rotatable drive screw 2 rotatably connected to the housing 1, and a rotatable driven screw 3 rotatably connected to the housing 1. When the discharge chamber 1.3 and the feed chamber 1.2 are vertically opposite each other, and the material conveying channel 1.4 extends vertically, both the drive screw 2 and the driven screw 3 are positioned vertically within the material conveying channel 1.4.

[0070] As attached Figure 2 As shown, two driven screws 3 are respectively placed on both sides of the driving screw 2, and both driven screws 3 are helically driven to the driving screw 2 through a threaded structure (the driving screw 2 has a first external thread extending in a helical shape on its outer periphery, and the driven screw 3 has a second external thread extending in a helical shape on its outer periphery and screwed into the first external thread).

[0071] The drive screw 2 is driven by a drive device 4, such as a rotary motor, that provides rotational force to it. The drive device 4 has an output shaft for outputting rotational power, which is driven by the drive screw 2 via a structure such as a coupling.

[0072] As attached Figure 1 As shown, the housing 1 is also provided with a pressure relief channel 1.5, one end of which is connected to the discharge chamber 1.3 and the other end of which is connected to the external space of the housing 1. The pressure relief channel 1.5 is used to discharge the material in the discharge chamber 1.3 to the external space of the housing 1.

[0073] As attached Figure 1 As shown, a pressure relief valve 5 is also provided in the pressure relief channel 1.5. The pressure relief valve 5 is configured to control the pressure relief channel 1.5 to be in a smooth discharge state or a blocked closed state when the hydraulic pressure in the discharge chamber 1.3 is greater than or not greater than a limit value (this limit value is set according to actual needs, for example, the limit value is the pressure value in the ultimate state when the discharge port 1.31 is blocked and the discharge chamber 1.3 is full of material).

[0074] For details, see attached. Figure 2 As shown, one end of the pressure relief channel 1.5 is a pressure relief port 1.51 connected to the discharge chamber 1.3, and the other end is a pressure discharge port 1.52 for discharging the material in the pressure relief channel 1.5 outward.

[0075] The pressure relief port 1.51 is located on the first side wall of the discharge chamber 1.3 (e.g., attached). Figure 1 The right side wall of the discharge chamber 1.3); and one port of the conveying channel 1.4, which connects to the discharge chamber 1.3, is located on the second side wall of the discharge chamber 1.3 (e.g., attached). Figure 1 The lower sidewall of the discharge chamber 1.3), the first sidewall and the second sidewall are arranged in a non-aligned manner.

[0076] Furthermore, the pressure relief channel 1.5 is configured to extend horizontally; that is, the axis of the pressure relief channel 1.5 is located in a certain horizontal plane. Simultaneously, the pressure relief port 1.51 is located on any side wall of the discharge chamber 1.3 in the horizontal direction; that is, the pressure relief port 1.51 is located on any one of the front, rear, left, or right side walls of the discharge chamber 1.3.

[0077] In the above scheme, the pressure relief valve 5 can be a solenoid valve that has a pressure sensor to detect the pressure in the discharge chamber 1.3 and controls the opening / closing of the pressure relief channel 1.5 through the pressure sensor.

[0078] Alternatively, the pressure relief valve 5 is a mechanical valve consisting of a pressure relief channel 1.5, a sealing element 5.1, and a pressure limiting element 5.2.

[0079] For details, see attached. Figure 2 As shown, in the direction from pressure relief port 1.51 to pressure discharge port 1.52, the pressure relief channel 1.5 sequentially includes: a first flow channel section 1.53 communicating with pressure relief port 1.51, and a second flow channel section 1.54 communicating with pressure discharge port 1.52. The end of the first flow channel section 1.53 away from pressure relief port 1.51 is connected to the second flow channel section 1.54, and the channel diameter of the second flow channel section 1.54 is larger than the channel diameter of the first flow channel section 1.53.

[0080] Meanwhile, the sealing component 5.1 is a block installed in the second flow channel section 1.54 and moving horizontally within the second flow channel section 1.54; the movement trajectory of the sealing component 5.1 extends to one end of the first flow channel section 1.53 away from the pressure relief port 1.51, so that the sealing component 5.1 can seal one end of the first flow channel section 1.53.

[0081] Furthermore, the outer diameter of the sealing element 5.1 is smaller than the channel diameter of the second flow channel section 1.54, so that a gap for material flow is formed between the outer wall of the sealing element 5.1 and the channel wall of the second flow channel section 1.54.

[0082] The pressure limiting member 5.2 is an elastic component that can provide elastic force by elastic deformation, such as a spring; it applies an elastic force to the sealing member 5.1 in a tensile or compressive manner to drive the sealing member 5.1 to seal one end of the first flow channel section 1.53.

[0083] The pressure limiting component 5.2 is selected or set according to the size of the limit value. When the pressure in the discharge chamber 1.3 is not greater than the limit value, it cannot overcome the elastic force generated by the pressure limiting component 5.2, and the sealing component 5.1 always seals one end of the first flow channel section 1.53. However, when the pressure in the discharge chamber 1.3 is greater than the limit value, it can overcome the elastic force generated by the pressure limiting component 5.2 and push the sealing component 5.1 away from the first flow channel section 1.53, so that the sealing component 5.1 does not seal one end of the first flow channel section 1.53.

[0084] Specifically, as one method, the second flow channel section 1.54 is fixed with a locking member 5.3 located on the side of the sealing member 5.1 facing away from the first flow channel section 1.53. A pressure limiting member 5.2 is compressedly disposed between the sealing member 5.1 and the locking member 5.3 so as to apply an elastic force to the sealing member 5.1 to drive it to seal one end of the first flow channel section 1.53.

[0085] Furthermore, the middle part of the locking component 5.3 is provided with a material passage 5.31 for material flowing from the pressure relief port 1.51 to the pressure discharge port 1.52 to pass through the locking component 5.3.

[0086] Alternatively, the second flow channel section 1.54 may be fixed with a retaining member 5.3 located on the side of the sealing member 5.1 facing away from the first flow channel section 1.53. A pressure limiting member 5.2 is compressedly disposed between the sealing member 5.1 and the retaining member 5.3 to apply an elastic force to the sealing member 5.1, causing it to seal one end of the first flow channel section 1.53.

[0087] Furthermore, the outer edge of the locking member 5.3 is provided with a slot, and the slot and the pipe wall of the second flow channel section 1.54 are intermittently formed to form a channel for material flowing from the pressure relief port 1.51 to the pressure discharge port 1.52 to pass through the locking member 5.3.

[0088] One end of the pressure limiting component 5.2 is positioned and connected to the sealing component 5.1 by a detachable connection method such as plug-in or a non-detachable connection method such as adhesive bonding, and the other end is positioned and connected to the locking component 5.3 by a detachable connection method such as plug-in or a non-detachable connection method such as adhesive bonding.

[0089] As attached Figure 2As shown, in this embodiment, the second flow channel segment 1.54 is a straight-extending channel. The locking member 5.3 is detachably fixed in the second flow channel segment 1.54, and the pressure discharge port 1.52 is located at the end of the second flow channel segment 1.54. The diameter of the pressure discharge port 1.52 is matched with the outline size of the locking member 5.3 so that the pressure discharge port 1.52 forms an opening for the locking member 5.3 to enter and exit the second flow channel segment 1.54.

[0090] For example, by forming an external thread on the outer periphery of the locking member 5.3, and forming an internal thread on the inner wall of the second flow channel section 1.54 that engages with the external thread of the locking member 5.3, the locking member 5.3 can be detachably fixed in the second flow channel section 1.54 through the threaded structure. By turning the locking member 5.3 in the forward or reverse direction, the locking member 5.3 can be fixed in or removed from the second flow channel section 1.54. At this time, the side of the locking member 5.3 facing the pressure outlet 1.52 is provided with a structure for a wrench to be inserted, such as an internal hexagonal socket.

[0091] As attached Figure 2 As shown, the sealing member 5.1 has a protruding guide portion 5.11 on the side facing the first flow channel section 1.53. The guide portion 5.11 is adapted to the channel diameter of the first flow channel section 1.53 and is configured to be inserted into one end of the first flow channel section 1.53 when the sealing member 5.1 seals one end of the first flow channel section 1.53.

[0092] Furthermore, the outer surface of the guide portion 5.11 is inclined and has a guide surface 5.12 for guiding the guide portion 5.11 into the first flow channel section 1.53. When the sealing member 5.1 seals one end of the first flow channel section 1.53, the port sidewall of the first flow channel section 1.53 abuts against the guide surface 5.12.

[0093] During normal operation of the three-screw pump unit:

[0094] The drive device 4 provides rotational power, which drives the active screw 2 to rotate. While the active screw 2 rotates, it drives the two driven screws 3 to rotate synchronously through the screw transmission structure. During this period, there will be continuous periodic volume changes between the screws and between the screws and the inner wall of the conveying channel 1.4, which can transport the material in the feed chamber 1.2 to the discharge chamber 1.3 and discharge it outward from the discharge port 1.31.

[0095] At this time, the pressure in the discharge chamber 1.3 is not greater than the limit value. The pressure limiting component 5.2 always applies an elastic force to the sealing component 5.1 to block one end of the first flow channel section 1.53, so that the pressure relief channel 1.5 is in a closed state of blockage. The material can only be discharged directionally from the discharge port 1.31 and will not be discharged from the pressure relief channel 1.5.

[0096] When blockage occurs at the discharge port 1.31 of the three-screw pump unit:

[0097] The drive unit 4 continuously drives the active screw 2 to rotate as described above, and continuously transports the material in the feed chamber 1.2 to the discharge chamber 1.3. As time progresses, the pressure in the discharge chamber 1.3 increases until it exceeds the limit value. At this time, the pressure value in the discharge chamber 1.3 is greater than the pressure value applied by the pressure limiting member 5.2 to the sealing member 5.1. The material will overcome the elastic force of the pressure limiting member 5.2 and push the sealing member 5.1 away from the port of the first flow channel section 1.53, so that the pressure relief channel 1.5 is in a smooth drainage state. The material in the discharge chamber 1.3 can be discharged outward from the pressure relief channel 1.5, thereby reducing the internal pressure of the discharge chamber 1.3 and better avoiding failures and damage caused by excessive internal pressure of the three-screw pump, so as to improve the overall operational stability and reliability of the three-screw pump device. Example 2:

[0098] The material conveying system includes the three-screw pump device described in any of the embodiments in Example 1.

[0099] As attached Figure 4 To be continued Figure 5 As shown, the material conveying system also includes a material box 6, which has a material cavity 6.1 for containing materials.

[0100] Furthermore, the material box 6 is connected to the three-screw pump device by a feed pipe 7 and a return pipe 8.

[0101] The feed pipe 7 has: one end connected to the feed port 1.21 of the three-screw pump device, and the other end connected to the material chamber 6.1, so as to guide the material in the material chamber 6.1 to the inlet channel 7.1 in the feed port 1.21.

[0102] The return pipe 8 has: one end connected to the pressure relief channel 1.5 of the three-screw pump device, and the other end connected to the material chamber 6.1, so that the material that has been depressurized to the pressure relief channel 1.5 can return to the return channel 8.1 in the material chamber 6.1.

[0103] As attached Figure 4 As shown, a pipe fitting 9 can be detachably inserted into the pressure relief port 1.52 of the pressure relief channel 1.5. This pipe fitting 9 has a protruding pipe connection 9.1 extending from the pressure relief channel 1.5. This pipe connection 9.1 is used to insert into one end of the return channel 8.1 to achieve a docking connection between the return pipe 8 and the three-screw pump device. Furthermore, the pipe fitting 9 internally forms a discharge channel 9.2 for discharging material from the pressure relief channel 1.5 into the return channel 8.1.

[0104] Thus, during normal operation of the three-screw pump unit:

[0105] The material in the material chamber 6.1 enters the feed chamber 1.2 through the feed pipe 7, flows through the conveying channel 1.4 and the discharge chamber 1.3, and is finally discharged directionally from the discharge port 1.31.

[0106] When the discharge port 1.31 of the three-screw pump unit is blocked:

[0107] The material discharged from the discharge chamber 1.3 into the pressure relief channel 1.5 will flow back to the material chamber 6.1 through the return pipe 8 for transportation and reuse, thus avoiding material waste.

[0108] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the scope of the present utility model. Furthermore, the terms "vertical," "horizontal," "front," and "rear," etc., mentioned in the embodiments of the present utility model, indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationships commonly used when the product is in use. They are only for the convenience of describing the present utility model and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present utility model. It should be further noted that, unless otherwise explicitly specified and limited, terms such as "installation," "connection," "joining," and "fixing" in the description should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, an indirect connection through an intermediate medium, or a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in the present utility model according to the specific circumstances.

[0109] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A three-screw pump device, comprising a housing (1) having therein: a feed chamber (1.2) communicating with a feed inlet (1.21), a discharge chamber (1.3) communicating with a discharge outlet (1.31), and a conveying channel (1.4) connecting the feed chamber (1.2) and the discharge chamber (1.3). The material conveying channel (1.4) contains: a rotatable driving screw (2) and two rotatable driven screws (3), the two driven screws (3) are respectively placed on both sides of the driving screw (2) and are both screwed to the driving screw (2); The active screw (2) is connected to a drive device (4) that provides rotational force to it. By driving the active screw (2) to rotate, the two driven screws (3) rotate synchronously, so as to transport the material in the feed chamber (1.2) to the discharge chamber (1.3). characterized in that The discharge chamber (1.3) is also connected to a pressure relief channel (1.5) for discharging the material in the discharge chamber (1.3) to the external space. The pressure relief channel (1.5) is provided with a pressure relief valve (5), which is configured to control the pressure relief channel (1.5) to be in a smooth discharge state or a blocked closed state when the hydraulic pressure in the discharge chamber (1.3) is greater than or not greater than a limit value.

2. The tri-screw pump apparatus of claim 1, wherein: One end of the pressure relief channel (1.5) is a pressure relief port (1.51) connected to the discharge chamber (1.3), and the other end is a pressure discharge port (1.52) for the material in the pressure relief channel (1.5) to be discharged outward. Furthermore, the pressure relief port (1.51) is located on the first side wall of the discharge chamber (1.3); The material conveying channel (1.4) is connected to one end of the discharge chamber (1.3) and is located on the second side wall of the discharge chamber (1.3); The first sidewall and the second sidewall are arranged in a non-aligned manner.

3. The tri-screw pump apparatus of claim 2, wherein: The pressure relief channel (1.5) is configured to extend horizontally. Furthermore, the pressure relief port (1.51) is located on any side wall of the discharge chamber (1.3) in the horizontal direction.

4. The tri-screw pump apparatus of any one of claims 2-3, wherein: In the direction from the pressure relief port (1.51) to the pressure discharge port (1.52), the pressure relief channel (1.5) sequentially includes: a first flow channel section (1.53) communicating with the pressure relief port (1.51), and a second flow channel section (1.54) communicating with the pressure discharge port (1.52). One end of the first flow channel section (1.53) is connected to the second flow channel section (1.54), and the channel diameter of the second flow channel section (1.54) is larger than the channel diameter of the first flow channel section (1.53); The pressure relief valve (5) includes: A sealing element (5.1) is installed in the second flow channel section (1.54) and can block one end of the first flow channel section (1.53), and a gap for material flow is formed between it and the channel wall of the second flow channel section (1.54); The resilient pressure limiting member (5.2) is configured to apply an elastic force to the plugging member (5.1) in a tensile or compressive manner, causing the plugging member (5.1) to block one end of the first flow channel section (1.53).

5. The tri-screw pump apparatus of claim 4, wherein: The second flow channel section (1.54) is fixed with a locking member (5.3) located on the side of the sealing member (5.1) facing away from the first flow channel section (1.53). The pressure limiting member (5.2) is compressedly disposed between the sealing member (5.1) and the locking member (5.3) to apply the elastic force to the sealing member (5.1); Furthermore, the middle part of the locking member (5.3) is provided with a material passage (5.31) through which the material flowing from the pressure relief port (1.51) to the pressure discharge port (1.52) passes through the locking member (5.3).

6. The tri-screw pump apparatus of claim 4, wherein: The second flow channel section (1.54) is fixed with a locking member (5.3) located on the side of the sealing member (5.1) facing away from the first flow channel section (1.53). The pressure limiting member (5.2) is compressedly disposed between the sealing member (5.1) and the locking member (5.3) to apply the elastic force to the sealing member (5.1); Furthermore, the outer edge of the locking member (5.3) is provided with a slot, and the slot and the pipe wall of the second flow channel section (1.54) are intermittently formed to form a channel for material flowing from the pressure relief port (1.51) to the pressure discharge port (1.52) to pass through the locking member (5.3).

7. The tri-screw pump apparatus of claim 5, wherein: The second flow channel section (1.54) is a straight-line extending channel; The locking member (5.3) is detachably fixed in the second flow channel section (1.54), and the pressure discharge port (1.52) is located at the end of the second flow channel section (1.54) and has an opening for the locking member (5.3) to enter and exit the second flow channel section (1.54).

8. The tri-screw pump apparatus of claim 4, wherein: The sealing member (5.1) has a protruding guide portion (5.11) on the side facing the first flow channel section (1.53). The guide portion (5.11) is adapted to the first flow channel section (1.53) and is configured to: when the sealing member (5.1) seals one end of the first flow channel section (1.53), it is adapted to be inserted into one end of the first flow channel section (1.53); Furthermore, the outer surface of the guide portion (5.11) is provided with an inclined guide surface (5.12) that guides the guide portion (5.11) to be inserted into the first flow channel section (1.53).

9. A material delivery system characterized by: It includes the three-screw pump device according to any one of claims 1 to 8.

10. The material delivery system of claim 9, wherein: The material conveying system also includes: The material box (6) has: a material cavity (6.1) for containing materials; The feed pipe (7) has: one end connected to the feed port (1.21) of the three-screw pump device, and the other end connected to the material chamber (6.1) to guide the material in the material chamber (6.1) to the inlet channel (7.1) in the feed port (1.21). The return pipe (8) has: one end connected to the pressure relief channel (1.5) of the three-screw pump device, and the other end connected to the material chamber (6.1) for the material that has been depressurized to the pressure relief channel (1.5) to return to the return channel (8.1) in the material chamber (6.1).

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