CN104864143B - Irrigation multifunctional mass-flow reducing valve - Google Patents

Abstract

The invention relates to a pressure reducing valve in the field of agricultural water-saving irrigation, which comprises a valve body, a support plate, a valve stem, a valve core, a valve cover, a base, an opening and closing valve, a spring positioning member, bolts and springs. Under working conditions, when the upstream pressure is unstable, under the action of the spring force and water pressure, the valve stem and valve core can move axially up and down to adjust the cross-flow section, resulting in local different head losses and stabilizing the downstream pressure. effect. The throttling port of the present invention is perpendicular to the direction of water flow, and the flow rate is large; the bottom end is provided with an opening and closing valve, and by adjusting the opening and closing valve, the valve core can be closely attached to the lower side wall of the throttling port to close the valve. The invention has the advantages of large flow rate, wide adjustment range, good pressure adjustment effect, and convenient assembly. It will greatly improve the uniformity of irrigation when used in agricultural irrigation systems; at the same time, the ingenious design of the opening and closing valve can save the switch in the pipeline. Valve, reduce investment.

Description

A multifunctional large flow pressure reducing valve for irrigation

technical field

The invention relates to a pressure reducing valve, in particular to a multifunctional large flow pressure reducing valve suitable for branch pipes of pipeline irrigation systems, belonging to the field of agricultural water-saving irrigation.

Background technique

In agricultural irrigation, irrigation uniformity is an important index to measure irrigation quality. However, due to differences in terrain and the distance between the head and the downstream irrigation plots, the water pressure at the entrance of each irrigation plot will change, resulting in irrigation uniformity that does not meet the specification requirements. In order to effectively control the irrigation uniformity of the entire irrigation system, it is a better solution to install pressure regulating equipment at the inlet branch pipes of each irrigation area, which can ensure that the inlet pressure of each irrigation area is the same.

Introduce the many deficiencies that existing pressure regulating valve exists according to accompanying drawing now. As shown in Fig. 14, it is a single-range pressure regulator in the prior art, mainly including a casing 1, a flower basket 2, a pressure regulating assembly 3 and a spring 4, which are composed of upper, middle and lower parts. Its pressure regulating mechanism is: the water flows through the flower basket 2 and enters the cavity of the pressure regulating component 3 to flow downstream. As the upstream pressure continues to increase, the downstream pressure also increases. Due to the force of the spring 4, the upstream pressure reaches a certain value. Before, the downstream end of the pressure regulating assembly 3 and the outlet have been kept in a tight state. When the upstream pressure continues to increase and the pressure acting on the downstream of the pressure regulating assembly 3 is greater than the sum of the initial compression stress of the spring 4 and the downstream pressure, the pressure regulator starts to play a regulating role, and the spring 4 is compressed under the combined force, and the pressure regulating assembly 3 Move to the upstream, at this time, the cross-sectional area of the inlet decreases, the head loss increases, and the downstream pressure decreases, so as to achieve the purpose of controlling the outlet pressure.

However, once the pressure regulator is assembled, only one preset pressure can be realized; and since the water flow only flows downstream through the cavity of the pressure regulating component, space will be wasted, and the volume of the entire device will be large if a large flow rate is to be realized.

As shown in Figure 15, it is a multi-range adjustable pressure reducing valve for irrigation in the prior art. Its pressure regulating mechanism is: when the upstream has a certain water pressure, the water flow enters the water inlet valve from the water inlet 19 chamber 30, and then enters the flow control chamber 26 through the diversion port 28, and then enters the water outlet valve chamber 25 through the water diversion port 29, and flows out from the water outlet 20. With the continuous increase of the upstream pressure, the downstream pressure also increases. Due to the spring 4 Due to the action of force, the support rod 14 and the valve top 17 will not move until the upstream pressure reaches a certain value. When the resultant force acting on the support rod 14 and the valve top 17 is greater than the force of the spring 4, the pressure regulating valve starts to work, and the valve top moves upwards. At this time, the cross-sectional area of the water decreases, the head loss increases, and the outlet pressure decreases. On the contrary, when the upstream pressure decreases, the spring 4 recovers under the action of the total pressure difference, the valve top 17 moves downstream, the cross-sectional area increases, the water head loss decreases, and the outlet pressure increases, so as to ensure the stability of the outlet pressure. There is a drive rod 6 at the top of the pressure regulating valve, and the outlet preset pressure can be changed by adjusting the drive rod 6 .

However, the flow rate of this pressure relief valve is only 5-15m ³ /h, which is difficult to meet the flow requirements of the branch pipes of the existing irrigation system; When 28 enters the flow control chamber 26, the split column will play a hindering role, the head loss will increase, and the starting pressure will be higher.

And when the above two devices are used in the pipeline irrigation system, they must be used in conjunction with the valve. When the irrigation of a wheel irrigation group is completed, the valve needs to be closed, that is, the above two devices have no closing and opening functions, so they cannot be used as valves. .

Therefore, there is an urgent need in the prior art for a pressure reducing valve for branch pipes of irrigation systems with large flow rate, adjustable outlet preset pressure, and opening and closing functions.

Contents of the invention

In view of the above problems, the present invention aims to provide a pressure reducing valve for branch pipes of irrigation systems with large flow rate, adjustable outlet preset pressure, good pressure regulation effect and opening and closing function. Further, the above-mentioned problems existing in the prior art are solved.

In order to achieve the above object, the present invention adopts the following technical solutions: a multifunctional large-flow pressure reducing valve for irrigation, which includes a valve body, a support plate, a valve stem, a valve core, a valve cover, a base and an opening and closing valve; The body is a straight-through cylindrical structure, one end of which is the water inlet end and the other end is the water outlet end. There is an opening on the upper and lower parts of the middle of the valve body, and the pipe wall at the lower opening extends outward for a certain distance to form a valve body. A circular opening with a flush bottom, the inner wall of the circular opening is provided with threads, and the pipe wall at the upper opening extends outward for a certain distance to form a circular opening with a flush top, and the upper opening The inner diameter of the extension section increases at two places, forming a first step and a second step, that is, the upper opening includes three sections with different inner diameters along the axial direction, and the end of the extension section of the upper opening expands along the radial direction of the outer wall to form a A square plate, each of which is provided with a drill hole near the edge at the four corners of the square plate; a baffle plate is arranged inside the valve body, and the baffle plate is in the shape of a slope step, and the baffle plate is close to the water inlet from the valve body Below the inner wall of the water end, there is an inclined upward extension section, followed by a horizontal extension section, and finally an inclined upward extension section, which is finally connected to the inner wall of the valve body near the water outlet. There is an opening on the horizontal extension section. As a throttling port, the upper opening, the lower opening and the central axis of the throttling port coincide; the main body of the supporting plate is a disc-shaped structure, and the center of the supporting plate is provided with a first through hole. The edge is provided with a first annular boss; the main body of the valve stem is a rod-shaped structure, which is divided into four sections according to the diameter of the outer wall, which are the first columnar section, the second columnar section, the third columnar section and the fourth columnar section. Section, the first columnar section at the top is used for spring positioning, the diameter of the second columnar section is larger than the diameter of the first columnar section, and the two ends of the second columnar section bear spring force and water pressure respectively, and the second columnar section There is a layer of rubber sealing cloth in the radial direction of the section. The bottom of the rubber sealing cloth is flush, and there is a bending section in the middle that plays a role in stretching. platform, the diameter of the third columnar section is smaller than the diameter of the first and second columnar sections, the diameter of the fourth columnar section is smaller than the diameter of the third columnar section, and the fourth columnar section is used to install the valve core; The main body of the valve core is a disc-shaped structure, the edge of the upper side wall of the valve core is provided with a third annular boss, and a circular rubber pad is arranged in the space surrounded by the third annular boss of the valve core, There is a second through hole in the middle of the valve core, the diameter of the second through hole should ensure that the fourth columnar section of the valve stem can just pass through; the main body of the valve cover is a hollow truncated cone Shaped structure, its lower end is provided with a circular opening, and the circular opening end expands radially along the outer wall to form another square plate, and the four corners of the other square plate are respectively provided with a drill hole near the edge, and the other The square plate and its drilling holes correspond to the size and position of the square plate and the drilling holes of the valve body respectively, and a fourth annular boss is axially extended on the inner end surface of the circular opening end, so that There is a third through hole on the top of the bonnet , the hole wall of the third through hole is provided with an annular extension along the axial direction to increase the length of the third through hole, the inner wall of the third through hole is provided with threads, and the outer wall of the valve cover is provided with several rows The air hole communicates with the inside of the valve cover and the outside atmosphere; the middle part of the base is a disc, and the center of the base is provided with a fourth through hole, and the fourth through hole of the base extends upward in the axial direction. A section of cylindrical body, a section of tetrahedral pedestal extends axially downward from the fourth through hole of the base, the fourth through hole penetrates the cylindrical body and the tetrahedral pedestal at the same time, the first The inner wall of the four through holes is provided with threads, the upper surface of the base is provided with an annular cylinder, the outer wall of the annular cylinder on the base is provided with threads, and the inner wall of the lower circular opening on the valve body is provided with threads. Threaded connection, the upper surface of the base is provided with an annular groove near the edge, which is used to install water-stop parts to ensure the seal between the valve body and the base; the opening and closing valve includes an integrally formed columnar body and a handle. The handle is vertically connected to one end of the columnar body, and the outer wall of the other end of the columnar body is provided with threads, which are matched with the threads on the inner wall of the fourth through hole of the base.

Further, the multifunctional large-flow pressure reducing valve for irrigation also includes a spring positioning member, bolts and springs, the spring positioning member is a disc, and a circular groove is arranged on one side of the outer wall of the spring positioning member, There is a boss on the other side of the outer wall; the bolt structure is similar to a commonly used screw, the lower end is a threaded cylindrical rod, the upper end is a hexagonal cylinder, and the cylindrical rod of the bolt rotates Extending into the third through hole at the upper end of the valve cover, the end of the columnar rod presses against the wall of the groove of the spring positioning member; the spring is placed in the inner space of the valve cover, One end is sleeved on the boss of the spring positioning member, and the other end is sleeved on the first columnar section of the valve rod, for exerting a downward driving tendency of the valve rod.

Further, the water inlet and outlet of the valve body are both set in the form of threads, and are connected to the irrigation system through threads.

Further, an O-ring seal is used between the base and the valve body.

Further, a layer of rubber sealing cloth is sandwiched between the second columnar section of the valve stem to prevent water from entering the cavity of the valve cover.

Further, the surrounding part of the third annular boss of the valve core is provided with a rubber pad to ensure that no water flows through when the valve is closed.

The present invention has adopted above technical scheme, has following beneficial effect:

1. The section of the orifice of the present invention is relatively large, and the initial distance between the spool and the orifice is relatively large, so the flow rate is large, which can meet the irrigation volume of 30-50m ³ /h; 2. The bonnet of the present invention is provided with a Bolt, the downstream preset pressure can be changed by adjusting the bolt, the adjustment range is wide, and the applicability is strong; 3. The base of the present invention is provided with an opening and closing valve, which can be closed by adjusting the handle, and the on-off valve can be omitted in the pipeline , saving investment; 4. Both ends of the baffle inside the valve body of the present invention are slope-shaped, and only the valve stem passes through the throttle, and there are no other obstacles around the throttle to ensure that the water head before the water flow passes through the throttle The loss is reduced to a minimum, which is beneficial to reduce the starting pressure; 5. The valve cover of the present invention is provided with a vent hole, which can ensure that the pressure in the valve cover cavity is always kept the same as the external atmospheric pressure, and ensures that the movement of the valve stem and the valve core is not affected. Influenced by air pressure; 6. The present invention can adjust the outlet preset pressure in a wider range only by changing the spring, which is easy to serialize; 7. The spring of the present invention is installed in the valve cover cavity, which is convenient for disassembly and maintenance. To sum up, the present invention has a large flow rate, wide adjustment range, good pressure regulation effect, and its own function of closing the pipeline, which is suitable for large-scale promotion and installed at the inlet of branch pipes, which will greatly improve the uniformity of irrigation.

Description of drawings

Fig. 1 is a schematic diagram under the initial state after assembly of the present invention;

Fig. 2 is a schematic diagram under the pressure regulating state in use of the present invention;

Fig. 3 is a schematic diagram of the external structure of the valve body of the present invention;

FIG. 4 is a schematic top view of FIG. 3;

Fig. 5 is the A-A sectional schematic diagram of Fig. 4;

Figure 6 is a schematic cross-sectional view of the middle part of the support plate of the present invention;

Fig. 7 is a schematic cross-sectional view of the middle part of the valve stem of the present invention;

Fig. 8 is a schematic cross-sectional view of the middle part of the spool of the present invention;

Fig. 9 is a schematic top view of a valve cover of the present invention;

Fig. 10 is a schematic cross-sectional view of A-A of Fig. 9;

Figure 11 is a schematic cross-sectional view of the middle part of the base of the present invention;

Fig. 12 is a schematic cross-sectional view of the middle part of the opening and closing valve of the present invention;

Fig. 13 is a schematic cross-sectional view of the middle part of the spring positioning member of the present invention;

Fig. 14 is a structural schematic diagram of a pressure regulator in the prior art;

Fig. 15 is a structural schematic diagram of a pressure regulating valve in the prior art.

detailed description

The preferred implementation method of the present invention will be described in detail below in conjunction with the accompanying drawings.

The present invention adopts the following technical solutions: a multifunctional large-flow pressure reducing valve for irrigation, as shown in Figure 1 and Figure 2, the present invention includes a valve body 1, a support plate 2, a valve stem 3, a valve core 4, and a valve cover 5 , base 6 and opening and closing valve 7.

As shown in Figure 3-5, the valve body 1 is a straight-through cylindrical structure, one end of which is the water inlet end 11, and the other end is the water outlet end 12; The pipe wall at the lower opening extends outward for a certain distance to form a circular opening with the bottom flush. The inner wall of the circular opening is provided with threads, and the circular opening end is the base connection end 13; The pipe wall at the upper opening extends outward for a certain distance to form a circular opening with a flush top. The inner diameter of the extension section of the upper opening increases at two places to form a first step 14 and a second step 15, namely the upper opening Contains three sections with different inner diameters in the axial direction, the end of the extension section of the upper opening expands along the radial direction of the outer wall to form a square plate 16, and each of the four corners of the square plate 16 has a drill hole 17 near the edge; A baffle plate 18 is provided inside the valve body 1, and the baffle plate is in the shape of a slope step. The baffle plate 18 has an inclined upward extension section from the bottom of the inner wall of the valve body 1 near the water inlet 11, and then another section The horizontal extension section, and finally continue an inclined upward extension section, and finally connect with the inner wall of the valve body 1 near the water outlet 12. There is an opening on the horizontal extension section as a throttle port 19; the upper opening, The lower opening coincides with the central axis of the orifice 19;

As shown in Figure 6, the main body of the support plate 2 is a disc-shaped structure, the center of the support plate 2 has a first through hole 22, and the edge of the support plate 2 is provided with a first annular boss 21; The support plate 2 is installed on the first step 14 of the upper opening of the valve body 1, and the first annular boss 21 is connected with the second step of the upper opening of the valve body 1. 15 steps are flush;

As shown in Figure 7, the main body of the valve rod 3 is a rod-shaped structure, which is divided into four sections according to the diameter of the outer wall, which are successively the first columnar section 31, the second columnar section 32, the third columnar section 33 and the fourth columnar section. Section 34, the first columnar section 31 at the top is used for spring positioning; the diameter of the second columnar section 32 is greater than the diameter of the first columnar section 31, and the two ends of the second columnar section 32 bear spring force and water pressure respectively; The second columnar section 32 is radially interposed with a layer of rubber sealing cloth 35, the bottom of which is flush with the bottom of the rubber sealing cloth 35, and there is a curved section in the middle which acts as a telescopic function. The outer edge of the rubber sealing cloth 35 is provided with a The ring plays the second annular boss 36 of positioning effect; The diameter of the third columnar section 33 is less than the diameter of the first and second columnar section 31; The diameter of the fourth columnar section 34 is less than the diameter of the third columnar section 33, The fourth columnar section 34 is used to install the valve core 4; when installed, the third columnar section 33 passes through the first through hole 22 in the center of the support plate 2, and the lower end surface of the second columnar section 32 Close to the upper surface of the disc of the support plate 2, the lower end surface of the edge of the rubber sealing cloth 35 is close to the second step 15 of the upper opening of the valve body 1 and the support plate 2 on the first annular boss 21;

As shown in Figure 8, the main body of the valve core 4 is a disc-shaped structure, the edge of the upper side wall of the valve core 4 is provided with a third annular boss 41, the space surrounded by the third annular boss 41 A circular rubber pad 42 is arranged inside; the middle position of the valve core 4 has a second through hole 43; when installed, the second through hole 43 of the valve core passes through the fourth columnar section 34 of the valve stem 3 , the rubber pad 42 is close to the interface between the third columnar section 33 and the fourth columnar section 34 of the valve stem 3;

As shown in Fig. 9 and Fig. 10, the main body of the valve cover 5 is a hollow truncated conical structure, and a circular opening is provided at its lower end, and the circular opening end expands radially along the outer wall to form another square plate 51, so that The four corners of another square plate 51 are respectively provided with a borehole 52 near the edge, and the other square plate 51 and its borehole 52 are respectively connected with the square plate 16 of the valve body 1 and the borehole 17 thereof. Corresponding in size and position; a fourth annular boss 53 is axially expanded on the inner end surface of the circular opening; the top end of the valve cover 5 is provided with a third through hole 54, and the third through hole 54 The wall of the hole is provided with a section of annular extension along the axial direction to increase the length of the third through hole 54, the inner wall of the third through hole 54 is provided with threads; the outer wall of the valve cover 5 is provided with a number of exhaust holes 55, It communicates with the inside of the valve cover 5 and the outside atmosphere; when installed, the other square plate 51 at the open end is close to the square plate 16 of the valve body 1, and the outer wall of the fourth annular boss 53 at the open end is close to the The inner wall surface of the annular boss 36 of the rubber gasket 35 of the valve stem 3 plays a role in fixing the rubber gasket 35;

As shown in Figure 11, the middle part of the base 6 is a disc 61, the center of the base 6 is provided with a fourth through hole 64, and the fourth through hole 64 of the base 6 is axially upward A section of cylindrical body 62 is extended, and a section of tetrahedral pillar 63 is extended axially downward at the fourth through hole 64 of the base 6, and the fourth through hole 64 penetrates the cylindrical body 62 and the fourth through hole 62 at the same time. Tetrahedral column 63, the inner wall of the fourth through hole is provided with threads; the upper surface of the base 6 is provided with a circle of annular cylinder 65, and the outer wall of the annular cylinder 65 is provided with threads, which are valve body connection ends An annular groove 66 is provided on the upper surface of the base 6 close to the edge for installing a water-stopping component to ensure the sealing between the valve body and the base; when installing, the annular cylinder 65 of the base 6 The outer wall and the inner wall of the lower opening end of the valve body 1 are connected by threads, and the upper side wall surface of the disc 61 is close to the end of the lower opening end of the valve body 1;

As shown in Figure 12, the opening and closing valve 7 includes an integrally formed cylindrical body 71 and a handle 72, the handle 72 is vertically connected to one end of the cylindrical body 71, and the outer wall surface of the cylindrical body 71 is provided with threads, Cooperate with the thread on the inner wall of the fourth through hole 64 of the base 6 . During installation, the columnar body 71 rotates and extends into the through hole 64 of the base 6, and is connected by threads;

Further, the present invention also includes a spring positioning member 8, a bolt and a spring;

As shown in Figure 13, the spring positioning member 8 is a disc, a circular groove 81 is provided on one side of the outer wall of the spring positioning member 8, and a boss 82 is provided on the other side of the outer wall; In the initial state, the side of the circular groove 81 on the spring positioning member 8 is close to the inner wall of the upper end of the valve cover 5;

The bolt structure is similar to a commonly used screw, the lower end is a threaded cylindrical rod, and the upper end is a hexagonal cylinder; in use, the cylindrical rod of the bolt rotates and extends into the upper end of the valve cover 5 In the third through hole 54, the end of the columnar rod presses against the wall surface of the groove 81 of the spring positioning member 8;

The spring 10 is placed in the inner space of the valve cover 5, one end is sleeved on the boss 82 of the spring positioning member 8, and the other end is sleeved on the first cylindrical section 31 of the valve stem 3 on, for exerting a downward drive tendency on the valve stem 3 .

Further, the water inlet end 11 and the water outlet end 12 of the valve body 1 are both set in the form of threads, which are connected to the irrigation system through threads;

Further, an O-ring seal is used between the base 6 and the valve body 1;

Further, a layer of rubber sealing cloth 35 is sandwiched between the second columnar section 32 of the valve stem 3 to prevent water from entering the cavity of the valve cover 5;

Further, the surrounding part of the third annular boss 41 of the valve core 4 is provided with a rubber pad 42 to ensure that no water flows through when the valve is closed.

The pressure regulating principle of the present invention is: as shown in Figure 1 and Figure 2, water flows in from the water inlet 11 of the valve body, passes through the throttle port 19, flows downstream along the wall of the valve core 4, and flows out from the water outlet 12 of the valve body. When there is water flow passing through, the main forces on the pressure reducing valve are: the force of upstream water flow acting on the lower side wall surface of the second columnar section 32 of the valve stem and the force on the rubber sealing cloth 35, the force of spring 10 acting on the valve stem 3, and the force of downstream water flow. The force on the upper and lower sides of the spool 4. When the upstream pressure is small, under the action of the prestress of the spring 10, the valve stem 3 and the valve core 4 will not be displaced. With the further increase of the upstream pressure, the downstream pressure will increase accordingly. When the upstream pressure increases to a certain When the value is one, under the action of the resultant force formed by the four forces, the valve stem 3 and the valve core 4 move upward, reducing the cross-flow section, increasing the local head loss, and reducing the downstream pressure; when the upstream pressure decreases, the valve stem 3 and the The spool 4 moves downwards to increase the flow cross section, reduce the local head loss, and increase the downstream pressure, so as to ensure that the downstream pressure is stable near the preset pressure. In addition, when there is no need to irrigate the water, you can manually rotate the opening and closing valve handle 72 upwards, squeeze the valve stem to drive the valve core 4 to move upward, so that the rubber pad 42 on the valve core 4 is close to the peripheral wall of the throttle port to ensure water flow. won't pass.

The above example is only an illustration of a preferred solution of the present invention, wherein the structure and connection mode of each part can be changed, and all equivalent transformations and improvements carried out on the basis of the present invention should be included in the protection scope of the present invention within.

Claims (6)

1. A multifunctional large-flow pressure reducing valve for irrigation, characterized in that: it includes a valve body, a support plate, a valve stem, a valve core, a valve cover, a base and an opening and closing valve; the valve body is a straight-through cylindrical structure , where one end is the water inlet end and the other end is the water outlet end. An opening is provided on the upper and lower parts of the valve body, and the pipe wall at the lower opening extends outward for a certain distance to form a circular ring with a flush bottom. Opening, the inner wall of the circular opening is provided with threads, and the pipe wall at the upper opening extends outward for a certain distance to form a circular opening with the top flush. The inner diameter of the extension section of the upper opening has two increase to form a first step and a second step, that is, the upper opening includes three sections with different inner diameters in the axial direction, and the end of the extension section of the upper opening expands along the radial direction of the outer wall to form a square plate, and the square plate Each of the four corners is provided with a drilling hole near the edge; the inside of the valve body is provided with a baffle, and the baffle is in the shape of a slope step, and the baffle has a slope from the bottom of the inner wall of the valve body near the water inlet. An upward extension section, followed by another horizontal extension section, and finally an oblique upward extension section, which is finally connected to the inner wall of the valve body near the water outlet. There is an opening on the horizontal extension section as a throttle. The upper opening, the lower opening, and the central axis of the orifice coincide; the main body of the support plate is a disc-shaped structure, a first through hole is provided in the center of the support plate, and a first annular protrusion is provided on the edge of the support plate. Taiwan; the main body of the valve rod is a rod-shaped structure, which is divided into four sections according to the diameter of the outer wall, which are the first columnar section, the second columnar section, the third columnar section and the fourth columnar section, and the first columnar section at the top section is used for spring positioning, the diameter of the second columnar section is greater than the diameter of the first columnar section, and the two ends of the second columnar section bear spring force and water pressure respectively, and a layer of Rubber sealing cloth, the bottom of the rubber sealing cloth is flush, and there is a curved section in the middle that plays a role in stretching. The outer edge of the rubber sealing cloth is provided with a second ring-shaped boss that plays a positioning role. The diameter is smaller than the diameter of the first and second columnar sections, the diameter of the fourth columnar section is smaller than the diameter of the third columnar section, and the fourth columnar section is used to install the valve core; the main body of the valve core is a circle Sheet structure, the edge of the upper wall surface of the valve core is provided with a third annular boss, a circular rubber pad is arranged in the space surrounded by the third annular boss of the valve core, and the middle position of the valve core has A second through hole, the diameter of the second through hole should ensure that the fourth columnar section of the valve stem can just pass through; the main body of the valve cover is a hollow truncated conical structure, and its lower end is provided with a A circular opening, the end of the circular opening expands radially along the outer wall to form another square plate, each of the four corners of the other square plate is provided with a drilling hole near the edge, and the other square plate and its drilling holes are respectively Corresponding to the square plate of the valve body and the size and position of the drilled hole, a fourth annular boss is axially extended on the inner end surface of the circular opening end, and the top end of the valve cover is provided with A third through hole, the hole wall of the third through hole is along the axial direction There is a circular extension in the upward direction to increase the length of the third through hole. The inner wall of the third through hole is provided with threads, and the outer wall of the valve cover is provided with a number of exhaust holes to communicate with the inside of the valve cover and the outside world. Atmosphere; the middle part of the base is a disc, the center of the base is provided with a fourth through hole, the fourth through hole of the base extends upward along the axial direction with a cylindrical body, the base of the base There is a section of tetrahedral column extending axially downward at the fourth through hole, the fourth through hole penetrates the cylindrical body and the tetrahedral column at the same time, the inner wall of the fourth through hole is provided with threads, An annular cylinder is arranged on the upper surface of the base, and the outer wall surface of the annular cylinder on the base is provided with threads, which are connected with the threads on the inner wall of the lower annular opening on the valve body. There is an annular groove near the edge, which is used to install water-stop parts to ensure the sealing between the valve body and the base; the opening and closing valve includes an integrally formed column and a handle, and the handle is connected to one end of the column. Vertically connected, the outer wall surface of the columnar body is provided with threads, which cooperate with the threads on the inner wall of the fourth through hole of the base. 2. A multi-functional large-flow relief valve for irrigation according to claim 1, characterized in that: it also includes a spring locator, a bolt and a spring, the spring locator is a disc, and the spring locator A circular groove is provided on one side of the outer wall, and a boss is provided on the other side of the outer wall; the bolt structure is similar to a commonly used screw, the lower end is a threaded columnar rod, and the upper end is a hexagonal The cylindrical rod of the bolt rotates and extends into the third through hole on the upper end of the valve cover, and the end of the cylindrical rod is pressed against the groove wall of the spring positioning member; The spring is placed in the inner space of the valve cover, one end is sleeved on the boss of the spring positioning member, and the other end is sleeved on the first cylindrical section of the valve stem, for applying the A downward driving tendency of the valve stem. 3. A multi-functional large-flow pressure reducing valve for irrigation according to any one of claims 1-2, characterized in that: the water inlet and outlet of the valve body are both set in the form of threads, which are connected into the Irrigation system. 4. A multi-functional large-flow pressure reducing valve for irrigation according to any one of claims 1-2, characterized in that: an O-ring seal is used between the base and the valve body. 5. A multifunctional large-flow pressure reducing valve for irrigation according to any one of claims 1-2, characterized in that a layer of rubber sealing cloth is sandwiched between the second columnar section of the valve stem to prevent water from entering the valve cover inside the cavity. 6. A multi-functional large-flow pressure reducing valve for irrigation according to any one of claims 1-2, characterized in that: the surrounding part of the third annular boss of the valve core is provided with a rubber pad to ensure that the valve Completely no water flow through when closed.