A constant differential pressure regulating system and differential pressure regulating valve

Abstract

The present application discloses a constant pressure difference regulating system and a differential pressure regulating valve, which belongs to the field of valve control technology, and solves the problem that the pressure difference between the mechanical seal cavity pressure and the sealing fluid pressure of the conveying equipment in the prior art is not constant, resulting in high safety hazards and easy damage to the mechanical seal. The input end of the first valve is connected between the output end of the power source circuit and the input end of the sealing circuit, the output end is connected to the input end of the differential pressure regulating valve, the output end of the differential pressure regulating valve is connected to the input end of the second valve, and the output end of the second valve is connected to the oil tank. The input end of the bypass regulating valve is connected to the input end of the first valve, and the output end is connected to the output end of the second valve. The pressure inlet pipe is connected to the pressure inlet port of the differential pressure regulating valve. The present application can regulate the sealing fluid pressure so that the sealing fluid pressure can change with the mechanical seal cavity pressure, and the pressure difference between the two is a constant value, which can not only eliminate safety hazards, but also extend the service life of the mechanical seal.

Description

Technical Field

[0001] The present application relates to the field of valve control technology, and in particular to a constant differential pressure regulating system and a differential pressure regulating valve. Background Art

[0002] At present, in the chemical industry, the input pressure of some equipment is a fluctuating value, so the pressure of its mechanical seal cavity also fluctuates with the input pressure. If the pressure of the mechanical seal cavity becomes higher, the sealing liquid pressure cannot increase accordingly, which will cause mechanical seal leakage. Chemical industry is a high-risk industry. Mechanical seal leakage will cause some toxic, harmful or dangerous media transported by the equipment to leak out, thus causing safety hazards. If the pressure of the mechanical seal cavity becomes lower, the sealing liquid pressure cannot decrease accordingly, which will cause the mechanical seal to be over-pressurized and damaged. Summary of the invention

[0003] The embodiments of the present application provide a constant pressure difference regulating system and a differential pressure regulating valve, thereby solving the problem in the prior art that the pressure difference between the mechanical seal cavity pressure and the blocking fluid pressure of the conveying equipment is not constant, resulting in high safety hazards and easy damage to the mechanical seal.

[0004] In the first aspect, an embodiment of the present invention provides a constant pressure difference regulation system, which includes a power source circuit, an inlet sealing circuit, an outlet sealing circuit, a differential pressure regulation circuit and an oil tank; the input end of the power source circuit is connected to the oil tank, and the output end is connected to the input end of the inlet sealing circuit, so as to realize constant flow and variable pressure transmission of the medium; the output end of the inlet sealing circuit is connected to the input end of the mechanical seal, so as to transport the sealing liquid to the mechanical seal; the input end of the outlet sealing circuit is connected to the output end of the mechanical seal, and the output end is connected to the oil tank, so as to output the sealing liquid; the differential pressure regulation circuit It includes a differential pressure regulating valve, a pressure-introducing pipe, a bypass regulating valve, a first valve and a second valve; the input end of the first valve is connected between the output end of the power source circuit and the input end of the inlet sealing circuit, the output end is connected to the input end of the differential pressure regulating valve, the output end of the differential pressure regulating valve is connected to the input end of the second valve, and the output end of the second valve is connected to the oil tank; the input end of the bypass regulating valve is connected to the input end of the first valve, and the output end is connected to the output end of the second valve; the pressure-introducing pipe is connected to the pressure inlet port of the differential pressure regulating valve, so as to introduce the pump chamber pressure into the differential pressure regulating valve.

[0005] In combination with the first aspect, in a possible implementation, the differential pressure regulating circuit further includes a back pressure valve; an input end of the back pressure valve is connected to an output end of the second valve, and an output end of the back pressure valve is connected to the oil tank.

[0006] In combination with the first aspect, in a possible implementation, the power source circuit includes a coarse filter, a volumetric pump and a one-way valve; the input end of the coarse filter is connected to the oil tank, and the output end is connected to the input end of the volumetric pump; the output end of the volumetric pump is connected to the input end of the one-way valve, and the output end of the one-way valve is connected to the input end of the sealing circuit.

[0007] In combination with the first aspect, in a possible implementation, the power source circuit also includes a relief valve; the input end of the relief valve is connected between the output end of the volumetric pump and the input end of the one-way valve, and the output end of the relief valve is connected to the oil tank.

[0008] In combination with the first aspect, in a possible implementation, the inlet sealing circuit includes a high-precision filter, a bladder accumulator, a differential pressure transmitter and an electromagnetic flowmeter; the input end of the high-precision filter is connected to the output end of the power source circuit, and the output end is connected to the input end of the electromagnetic flowmeter; the output end of the electromagnetic flowmeter is connected to the input end of the mechanical seal; the differential pressure transmitter and the high-precision filter are connected in parallel; the bladder accumulator is connected between the output end of the power source circuit and the input end of the high-precision filter.

[0009] In combination with the first aspect, in a possible implementation, the outlet sealing circuit includes a flow regulating valve and a heat exchanger; the input end of the flow regulating valve is connected to the output end of the mechanical seal, and the output end is connected to the input end of the heat exchanger; the output end of the heat exchanger is connected to the oil tank.

[0010] In combination with the first aspect, in a possible implementation, the constant pressure difference regulation system also includes a pressure maintaining branch; the pressure maintaining branch includes a first hydraulically controlled one-way valve and a second hydraulically controlled one-way valve; the input end of the first hydraulically controlled one-way valve is connected to the output end of the inlet sealing circuit, and the output end is connected to the input end of the mechanical seal; the input end of the second hydraulically controlled one-way valve is connected to the output end of the mechanical seal, and the output end is connected to the input end of the outlet sealing circuit.

[0011] In the second aspect, an embodiment of the present invention provides a differential pressure regulating valve, which is used in the above-mentioned constant pressure difference regulating system, wherein the differential pressure regulating valve includes a valve body, a valve core and an adjusting mechanism; the adjusting mechanism includes a bellows shell, an adjusting structure, an adjusting bolt, an upper cover, a valve core guide sleeve and a guide sleeve pressure ring; an input end and an output end are arranged on the valve body; the bellows shell is connected to the top of the valve body; the upper cover is arranged at the end of the bellows shell away from the valve body; the adjusting bolt is threadedly connected to the upper cover, and the threaded end of the adjusting bolt passes through the upper cover and abuts against the top end of the adjusting structure; the end of the adjusting structure away from the adjusting bolt is located at the bellows shell. The valve core guide sleeve and the guide sleeve pressure ring are both sleeved on the valve core; the valve core guide sleeve is connected to the valve body and is located at the top of the valve body; a first through hole is provided on the valve core guide sleeve, the input end of the first through hole is connected to the input end of the valve body, and the output end of the first through hole is connected to the inner cavity of the bellows housing; the guide sleeve pressure ring is located in the inner cavity of the bellows housing, one end of the guide sleeve pressure ring is abutted against the valve core guide sleeve, and the other end is abutted against the adjusting structure; a pressure inlet is provided on the upper cover, and the pressure inlet is connected to the inner cavity of the adjusting structure.

[0012] In combination with the second aspect, in a possible implementation, the adjustment structure includes a bellows positioning seat, a bellows assembly, a balancing spring, a balancing spring pressure ring and a stroke limit rod; the bellows positioning seat is installed in the inner cavity of the bellows housing and is located at the bottom end of the bellows housing; one end of the bellows assembly is connected between the bellows housing and the upper cover, and the other end extends into the bellows housing and is connected to the valve core; the balancing spring is arranged in the inner cavity of the bellows assembly, one end of the balancing spring is connected to the bottom end of the bellows assembly, and the other end is connected to the balancing spring pressure ring; one end of the balancing spring pressure ring facing away from the balancing spring abuts against the threaded end of the adjusting bolt; one end of the stroke limit rod is connected to the balancing spring pressure ring, and the other end is located in the balancing spring.

[0013] In combination with the second aspect, in a possible implementation, the adjustment mechanism also includes an adjustment rod cover; the adjustment rod cover is connected to an end of the upper cover that faces away from the adjustment structure; and the head of the adjustment bolt is located in the inner cavity of the adjustment rod cover.

[0014] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0015] The embodiment of the present invention provides a constant pressure difference regulating system, which includes a power source circuit, an inlet sealing circuit, an outlet sealing circuit, a differential pressure regulating circuit and an oil tank. The input end of the power source circuit is connected to the oil tank, and the output end is connected to the input end of the inlet sealing circuit, so as to realize constant flow variable pressure transmission of the medium. The output end of the inlet sealing circuit is connected to the input end of the mechanical seal, so as to transport the blocking liquid to the mechanical seal. The input end of the outlet sealing circuit is connected to the output end of the mechanical seal, and the output end is connected to the oil tank for outputting the blocking liquid. The differential pressure regulating circuit includes a differential pressure regulating valve, a pressure lead pipe, a bypass regulating valve, a first valve and a second valve. The input end of the first valve is connected between the output end of the power source circuit and the input end of the inlet sealing circuit, the output end is connected to the input end of the differential pressure regulating valve, the output end of the differential pressure regulating valve is connected to the input end of the second valve, and the output end of the second valve is connected to the oil tank. The input end of the bypass regulating valve is connected to the input end of the first valve, and the output end is connected to the output end of the second valve. The pressure inlet pipe is connected to the pressure inlet port of the differential pressure regulating valve to introduce the pump chamber pressure into the differential pressure regulating valve. The present application can adjust the sealing liquid pressure so that the sealing liquid pressure can change with the mechanical seal cavity pressure and keep the pressure difference between the two constant, which can not only eliminate safety hazards but also extend the service life of the mechanical seal. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0017] Figure 1 A system schematic diagram of a constant pressure difference regulation system provided in an embodiment of the present application;

[0018] Figure 2 A schematic diagram of a power source circuit provided in an embodiment of the present application;

[0019] Figure 3 A schematic diagram of a differential pressure regulating circuit provided in an embodiment of the present application;

[0020] Figure 4 A schematic diagram of a sealing circuit provided in an embodiment of the present application;

[0021] Figure 5 A schematic diagram of a sealing circuit provided in an embodiment of the present application;

[0022] Figure 6 A schematic diagram of the structure of a differential pressure regulating valve provided in an embodiment of the present application.

[0023] Icons: 1-power source circuit; 11-coarse filter; 12-displacement pump; 13-check valve; 14-relief valve; 2-inlet sealing circuit; 21-high-precision filter; 22-bladder accumulator; 23-pressure differential transmitter; 24-electromagnetic flowmeter; 3-outlet sealing circuit; 31-flow control valve; 32-heat exchanger; 4-differential pressure control circuit; 41-differential pressure control valve; 411-valve body; 412-valve core; 413-regulating mechanism; 4131-bellows housing; 4132-regulating structure; 41321-bellows positioning seat; 41322-adjusting structure; 4132 ... 1322- bellows assembly; 41323- balance spring; 41324- balance spring pressure ring; 41325- travel limit rod; 4133- adjusting bolt; 4134- upper cover; 4135- upper cover baffle; 4136- valve core guide sleeve; 4137- guide sleeve pressure ring; 4138- adjusting rod cover; 42- pressure guide pipe; 43- bypass regulating valve; 44- first valve; 45- second valve; 46- back pressure valve; 5- oil tank; 6- mechanical seal; 7- pressure maintaining branch; 71- first hydraulically controlled one-way valve; 72- second hydraulically controlled one-way valve. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] In the description of the embodiments of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than indicating or implying that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limitations on the present invention. The terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. In addition, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be a connection inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0026] like Figures 1 to 5As shown, an embodiment of the present invention provides a constant pressure difference regulation system, which includes a power source circuit 1, an inlet sealing circuit 2, an outlet sealing circuit 3, a differential pressure regulation circuit 4 and an oil tank 5. The input end of the power source circuit 1 is connected to the oil tank 5, and the output end is connected to the input end of the inlet sealing circuit 2, so as to realize constant flow variable pressure transmission of the medium. The output end of the inlet sealing circuit 2 is connected to the input end of the mechanical seal 6, so as to transport the sealing liquid to the mechanical seal 6. The input end of the outlet sealing circuit 3 is connected to the output end of the mechanical seal 6, and the output end is connected to the oil tank 5, so as to output the sealing liquid. In practical applications, since the mechanical seal 6 of the pump requires an external sealing liquid flushing to ensure the normal operation of the pump, the pressure of the sealing liquid is 0.3Mpa higher than the pressure of the mechanical seal 6 cavity, but the pressure of the mechanical seal 6 cavity of the pump is often a variable value in chemical engineering, so the power source circuit 1 is required to realize constant flow variable pressure transmission of the medium.

[0027] like Figure 3 As shown, the differential pressure regulating circuit 4 includes a differential pressure regulating valve 41, a pressure-introducing pipe 42, a bypass regulating valve 43, a first valve 44, and a second valve 45. The input end of the first valve 44 is connected between the output end of the power source circuit 1 and the input end of the sealing circuit 2, the output end is connected to the input end of the differential pressure regulating valve 41, the output end of the differential pressure regulating valve 41 is connected to the input end of the second valve 45, and the output end of the second valve 45 is connected to the oil tank 5. The input end of the bypass regulating valve 43 is connected to the input end of the first valve 44, and the output end is connected to the output end of the second valve 45. The pressure-introducing pipe 42 is connected to the pressure-introducing port of the differential pressure regulating valve 41, and is used to introduce the pump chamber pressure into the differential pressure regulating valve 41. In actual use, the pressure difference is first adjusted to a certain value through the bypass regulating valve 43, and then the pressure-introducing pipe 42 is connected to introduce the pump chamber pressure, and the second valve 45 is opened at the same time, and then the bypass regulating valve 43 is gradually closed, and the first valve 44 is opened while closing the bypass regulating valve 43, until the bypass regulating valve 43 is fully closed and the first valve 44 is fully opened, at which time the differential pressure regulating valve 41 can be put into operation. Specifically, the differential pressure regulating circuit 4 adjusts the sealing liquid pressure through the differential pressure regulating valve 41, so that the sealing liquid pressure can change with the cavity pressure of the mechanical seal 6, and the pressure difference between the two is a constant value, which can not only eliminate safety hazards, but also extend the service life of the mechanical seal 6.

[0028] The embodiment of the present invention provides a constant pressure difference regulation system, which includes a power source circuit 1, an inlet sealing circuit 2, an outlet sealing circuit 3, a differential pressure regulation circuit 4 and an oil tank 5. The input end of the power source circuit 1 is connected to the oil tank 5, and the output end is connected to the input end of the inlet sealing circuit 2, so as to realize constant flow variable pressure transmission of the medium. The output end of the inlet sealing circuit 2 is connected to the input end of the mechanical seal 6, so as to transport the blocking liquid to the mechanical seal 6. The input end of the outlet sealing circuit 3 is connected to the output end of the mechanical seal 6, and the output end is connected to the oil tank 5, so as to output the blocking liquid. The differential pressure regulation circuit 4 includes a differential pressure regulating valve 41, a pressure lead pipe 42, a bypass regulating valve 43, a first valve 44 and a second valve 45. The input end of the first valve 44 is connected between the output end of the power source circuit 1 and the input end of the inlet sealing circuit 2, the output end is connected to the input end of the differential pressure regulating valve 41, the output end of the differential pressure regulating valve 41 is connected to the input end of the second valve 45, and the output end of the second valve 45 is connected to the oil tank 5. The input end of the bypass regulating valve 43 is connected to the input end of the first valve 44, and the output end is connected to the output end of the second valve 45. The pressure-introducing pipe 42 is connected to the pressure-introducing port of the differential pressure regulating valve 41, and is used to introduce the pump chamber pressure into the differential pressure regulating valve 41. The present application can adjust the sealing liquid pressure so that the sealing liquid pressure can change with the pressure of the mechanical seal 6 cavity, and the pressure difference between the two is a constant value, which can not only eliminate safety hazards, but also extend the service life of the mechanical seal 6.

[0029] Continue to refer to Figure 3 As shown, the differential pressure regulating circuit 4 also includes a back pressure valve 46. The input end of the back pressure valve 46 is connected to the output end of the second valve 45, and the output end of the back pressure valve 46 is connected to the oil tank 5. During the system regulation process, due to the small flow rate and the guaranteed regulation pressure difference, the system pipeline is prone to pressure instability, so the back pressure valve 46 is installed at the output end of the differential pressure regulating valve 41 to cooperate with the differential pressure regulating valve 41 to perform pressure regulation so that the differential pressure is within the required range.

[0030] like Figure 2 As shown, the power source circuit 1 includes a coarse filter 11, a positive displacement pump 12 and a one-way valve 13. The input end of the coarse filter 11 is connected to the oil tank 5, and the output end is connected to the input end of the positive displacement pump 12. The output end of the positive displacement pump 12 is connected to the input end of the one-way valve 13, and the output end of the one-way valve 13 is connected to the input end of the sealing circuit 2. Specifically, the positive displacement pump 12 includes a quantitative gear pump. During the operation of the quantitative gear pump, the flow rate of the pumped medium is constant and the relative pressure pulsation is small. Its output pressure can change with the change of the system resistance, which can not only realize the constant flow and variable pressure conveying of the medium, but also ensure the long-term and stable operation of the system.

[0031] Continue to refer to Figure 2As shown, the power source circuit 1 also includes a relief valve 14. The input end of the relief valve 14 is connected between the output end of the volumetric pump 12 and the input end of the one-way valve 13, and the output end of the relief valve 14 is connected to the oil tank 5. Specifically, the provision of the relief valve 14 can improve the safety performance of the system and avoid damage to the on-site equipment caused by unexpected high pressure in the system.

[0032] like Figure 4 As shown, the inlet sealing circuit 2 includes a high-precision filter 21, a bladder accumulator 22, a differential pressure transmitter 23 and an electromagnetic flowmeter 24. The input end of the high-precision filter 21 is connected to the output end of the power source circuit 1, and the output end is connected to the input end of the electromagnetic flowmeter 24. The output end of the electromagnetic flowmeter 24 is connected to the input end of the mechanical seal 6. In practical applications, the high-precision filter 21 can filter out impurities in the oil product to avoid contamination of the sealing liquid during use, which may cause the oil product to deteriorate at high temperature or freeze at low temperature. The electromagnetic flowmeter 24 is used to detect the flow rate to ensure that the flow rate can meet the requirements.

[0033] In practical applications, the differential pressure transmitter 23 is connected in parallel with the high-precision filter 21. Specifically, the differential pressure transmitter 23 can monitor the pressure difference between the input end and the output end of the high-precision filter 21, and timely determine whether the high-precision filter 21 is blocked.

[0034] Continue to refer to Figure 4 As shown, the bladder accumulator 22 is connected between the output end of the power source circuit 1 and the input end of the high-precision filter 21. Specifically, the bladder accumulator 22 can effectively absorb the pressure pulsation generated during the operation of the positive displacement pump 12. In practical applications, the bladder accumulator 22 is equipped with a pressure transmitter to detect the pressure of the main sealing liquid line.

[0035] like Figure 5 As shown, the sealing circuit 3 includes a flow regulating valve 31 and a heat exchanger 32. The input end of the flow regulating valve 31 is connected to the output end of the mechanical seal 6, and the output end is connected to the input end of the heat exchanger 32. The output end of the heat exchanger 32 is connected to the oil tank 5. Specifically, the flow regulating valve 31 can ensure that the flushing flow meets the requirements. In practical applications, a large amount of heat will be generated on the surface of the friction pair during the operation of the mechanical seal 6. The industrial white oil is used as a sealing liquid to provide lubrication for the friction pair of the mechanical seal 6 while taking away the heat from the surface of the friction pair. Therefore, the heat exchanger 32 is set to cool the sealing liquid, and an appropriate cooling water flow rate is selected according to the oil temperature. In addition, during the system shutdown period, the white oil is preheated by the built-in electric heater in the oil tank 5 to prevent the white oil from solidifying at low temperatures and ensure that the white oil temperature is controlled within the design temperature range.

[0036] like Figure 1 , Figure 4 and Figure 5As shown, the constant pressure difference regulation system also includes a pressure maintaining branch 7. The pressure maintaining branch 7 includes a first hydraulically controlled one-way valve 71 and a second hydraulically controlled one-way valve 72. The input end of the first hydraulically controlled one-way valve 71 is connected to the output end of the inlet sealing circuit 2, and the output end is connected to the input end of the mechanical seal 6. The input end of the second hydraulically controlled one-way valve 72 is connected to the output end of the mechanical seal 6, and the output end is connected to the input end of the outlet sealing circuit 3. Specifically, the hydraulic control lines of the first hydraulically controlled one-way valve 71 and the second hydraulically controlled one-way valve 72 are from the pump outlet sealing liquid main pipe. If the system is powered off or other reasons cause the pump to fail to work normally, the second hydraulically controlled one-way valve 72 is closed to cut off the return oil main line at the output end of the mechanical seal 6, and the first hydraulically controlled one-way valve 71 is closed to cut off the sealing liquid oil inlet line at the input end of the mechanical seal 6. At this time, the bladder accumulator 22 realizes the shutdown pressure maintaining function to ensure that the mechanical seal 6 remains in a positive pressure state when the system is powered off.

[0037] like Figure 6 As shown, an embodiment of the present invention provides a differential pressure regulating valve, which is used in the above-mentioned constant differential pressure regulating system, and the differential pressure regulating valve 41 includes a valve body 411, a valve core 412 and an adjusting mechanism 413. The adjusting mechanism 413 includes a bellows housing 4131, an adjusting structure 4132, an adjusting bolt 4133, an upper cover 4134, a valve core guide sleeve 4136 and a guide sleeve pressure ring 4137. An input end and an output end are provided on the valve body 411. The bellows housing 4131 is connected to the top of the valve body 411. The upper cover 4134 is arranged at one end of the bellows housing 4131 away from the valve body 411. The adjusting bolt 4133 and the upper cover 4134 are threadedly connected, and the threaded end of the adjusting bolt 4133 passes through the upper cover 4134 and abuts against the top of the adjusting structure 4132. Specifically, since the threaded end of the adjusting bolt 4133 passes through the upper cover 4134, there is a gap between the adjusting bolt 4133 and the upper cover 4134, so an upper cover baffle 4135 is provided on the upper cover 4134 to prevent the medium from leaking out from the gap between the adjusting bolt 4133 and the upper cover 4134. In addition, a sealing ring is provided between the upper cover baffle 4135 and the upper cover 4134 to play a sealing role.

[0038] In practical applications, the end of the adjusting structure 4132 that faces away from the adjusting bolt 4133 is located in the inner cavity of the bellows housing 4131, and its end is connected to the valve core 412 to drive the valve core 412 to move up and down in the valve body 411. The valve core guide sleeve 4136 and the guide sleeve pressure ring 4137 are both sleeved on the valve core 412. The valve core guide sleeve 4136 is connected to the valve body 411 and is located at the top of the valve body 411. A first through hole is provided on the valve core guide sleeve 4136, and the input end of the first through hole is connected to the input end of the valve body 411, and the output end of the first through hole is connected to the inner cavity of the bellows housing 4131. Specifically, the blocking liquid pressure is introduced into the inner cavity of the bellows housing 4131 through the first through hole on the valve core guide sleeve 4136.

[0039] like Figure 6 As shown, the guide sleeve pressure ring 4137 is located in the inner cavity of the bellows housing 4131, one end of the guide sleeve pressure ring 4137 abuts against the valve core guide sleeve 4136, and the other end abuts against the adjustment structure 4132. A pressure inlet is provided on the upper cover 4134, and the pressure inlet is connected to the inner cavity of the adjustment structure 4132. In actual application, the pressure of the mechanical seal 6 cavity is introduced into the inner cavity of the adjustment structure 4132 through the pressure inlet.

[0040] When the differential pressure regulating valve 41 of the embodiment of the present invention is in use, if the pressure difference of the differential pressure regulating valve 41 is inconsistent with the required pressure difference, first tighten the adjusting bolt 4133 to move the adjusting bolt 4133 upward or downward, and the adjusting bolt 4133 moves up and down to make the adjusting structure 4132 move up and down. The up and down movement of the adjusting structure 4132 drives the valve core 412 to move up and down. The up and down movement of the valve core 412 realizes the adjustment of the opening size of the differential pressure regulating valve 41, so as to adjust the pressure difference of the differential pressure regulating valve 41 to the required value. When the pressure in the cavity of the mechanical seal 6 changes, the valve core 412 will be driven to move up and down, so that the valve opening of the differential pressure regulating valve 41 will change, and the system resistance will also change accordingly (when the pressure in the cavity of the mechanical seal 6 increases, the valve core 412 moves downward, the valve opening decreases, the system resistance increases, and the output pressure of the blocking liquid increases, thereby pushing the valve core 412 to move upward, the valve opening gradually increases, and returns to a balanced state; similarly, when the pressure in the cavity of the mechanical seal 6 decreases, the valve core 412 moves upward, the valve opening increases, the system resistance decreases, and the output pressure of the blocking liquid decreases, thereby pushing the valve core 412 to move downward, the valve opening gradually decreases, and returns to a balanced state again).

[0041] Continue to refer to Figure 6As shown, the adjustment structure 4132 includes a bellows positioning seat 41321, a bellows assembly 41322, a balance spring 41323, a balance spring pressure ring 41324 and a travel limit rod 41325. The bellows positioning seat 41321 is installed in the inner cavity of the bellows housing 4131 and is located at the bottom end of the bellows housing 4131. The bellows positioning seat 41321 limits the compression amount of the balance spring 41323 to ensure that the balance spring 41323 is within a certain safe compression amount.

[0042] In practical applications, one end of the bellows assembly 41322 is connected between the bellows housing 4131 and the upper cover 4134, and the other end extends into the bellows housing 4131 and is connected to the valve core 412. The balance spring 41323 is arranged in the inner cavity of the bellows assembly 41322, one end of the balance spring 41323 is connected to the bottom end of the bellows assembly 41322, and the other end is connected to the balance spring compression ring 41324. Specifically, the bellows assembly 41322 seals the balance spring 41323 inside, isolates the sealing liquid pressure and the mechanical seal 6 cavity pressure, and the pressure difference between the inside and outside of the bellows assembly 41322 is the pressure of the balance spring 41323. In addition, the medium introduced by the pressure inlet is generally a highly corrosive medium in the chemical industry. The medium is isolated by the bellows assembly 41322. Only the parts of the upper end of the differential pressure regulating valve 41 that are in contact with the medium, such as the balance spring 41323, the upper cover 4134, the balance spring pressure ring 41324 and the bellows assembly 41322, need to be set to corrosion-resistant materials, and other parts do not need to be set to corrosion-resistant materials, thereby reducing the manufacturing cost of the differential pressure regulating valve 41. According to the principle of force balance of the valve core 412, the pressure of the controlled liquid flow (blocking liquid) is used to balance the force of the valve core 412 and other forces (mainly the spring force of the balance spring 41323) to adjust the opening of the valve to change the size of the resistance, thereby achieving the effect of controlling the liquid flow pressure. The blocking liquid pressure = the pressure of the mechanical seal 6 cavity + the elastic force of the balance spring 41323, where the elastic force of the balance spring 41323 is the pressure difference generated by the two pressure sources. Balanced state: When the valve is at a certain opening, while ensuring that the flow meets the use conditions, the system resistance generated makes the sealing liquid pressure greater than the pressure of the mechanical seal 6 cavity, and the pressure difference is the elastic force generated by the balance spring 41323.

[0043] like Figure 6As shown, one end of the balance spring compression ring 41324 that faces away from the balance spring 41323 abuts against the threaded end of the adjusting bolt 4133. One end of the travel limit rod 41325 is connected to the balance spring compression ring 41324, and the other end is located in the balance spring 41323. If the pressure difference of the differential pressure regulating valve 41 is inconsistent with the required pressure difference, first turn the adjusting bolt 4133 to move the adjusting bolt 4133 upward or downward, and the upward and downward movement of the adjusting bolt 4133 drives the balance spring compression ring 41324 to move up and down, and the upward and downward movement of the balance spring compression ring 41324 drives the travel limit rod 41325 to move up and down and adjust the compression amount of the balance spring 41323. The elastic force generated by the balance spring 41323 is the required pressure difference value of the two pressure sources. In the balanced state, for the valve core 412, the pressure of the mechanical seal 6 cavity + the elastic force of the balance spring 41323 = the sealing liquid pressure. When the pressure in the cavity of the mechanical seal 6 changes, the valve core 412 will be driven to move up and down, so that the valve opening of the differential pressure regulating valve 41 will change, and the system resistance will also change accordingly (when the pressure in the cavity of the mechanical seal 6 increases, the valve core 412 moves downward, the valve opening decreases, the system resistance increases, and the output pressure of the blocking liquid increases, thereby pushing the valve core 412 to move upward, the valve opening gradually increases, and returns to a balanced state; similarly, when the pressure in the cavity of the mechanical seal 6 decreases, the valve core 412 moves upward, the valve opening increases, the system resistance decreases, and the output pressure of the blocking liquid decreases, thereby pushing the valve core 412 to move downward, the valve opening gradually decreases, and returns to a balanced state again).

[0044] In practical applications, the adjustment mechanism 413 further includes an adjustment rod cover 4138. The adjustment rod cover 4138 is connected to an end of the upper cover 4134 that is away from the adjustment structure 4132. The head of the adjustment bolt 4133 is located in the inner cavity of the adjustment rod cover 4138. The adjustment rod cover 4138 can seal the adjustment bolt 4133 to prevent dust from entering the adjustment bolt 4133 and causing obstruction, resulting in the inability to adjust the adjustment bolt 4133. At the same time, the adjustment rod cover 4138 can also prevent the occurrence of safety accidents caused by accidentally touching the adjustment bolt 4133.

[0045] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other. Each embodiment focuses on the differences from other embodiments.

[0046] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit the present application. Although the present application has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present application.

Claims

1. A constant pressure difference regulation system, characterized in that: It comprises a power source circuit (1), an inlet sealing circuit (2), an outlet sealing circuit (3), a differential pressure regulating circuit (4) and an oil tank (5); The input end of the power source circuit (1) is connected to the oil tank (5), and the output end is connected to the input end of the inlet sealing circuit (2), so as to realize constant flow and variable pressure transmission of the medium; The output end of the sealing circuit (2) is connected to the input end of the mechanical seal (6) for delivering the sealing liquid to the mechanical seal (6); The input end of the outlet sealing circuit (3) is connected to the output end of the mechanical seal (6), and the output end is connected to the oil tank (5) for outputting the sealing liquid; The differential pressure regulating circuit (4) comprises a differential pressure regulating valve (41), a pressure guide pipe (42), a bypass regulating valve (43), a first valve (44) and a second valve (45); The input end of the first valve (44) is connected between the output end of the power source circuit (1) and the input end of the inlet sealing circuit (2), the output end is connected to the input end of the differential pressure regulating valve (41), the output end of the differential pressure regulating valve (41) is connected to the input end of the second valve (45), and the output end of the second valve (45) is connected to the oil tank (5); The input end of the bypass regulating valve (43) is connected to the input end of the first valve (44), and the output end is connected to the output end of the second valve (45); The pressure-introducing pipe (42) is connected to the pressure-introducing port of the differential pressure regulating valve (41) and is used to introduce the pump chamber pressure into the differential pressure regulating valve (41); The differential pressure regulating valve (41) comprises a valve body (411), a valve core (412) and a regulating mechanism (413); The regulating mechanism (413) comprises a bellows housing (4131), an regulating structure (4132), an regulating bolt (4133), an upper cover (4134), a valve core guide sleeve (4136) and a guide sleeve pressure ring (4137); The valve body (411) is provided with an input end and an output end; The bellows housing (4131) is connected to the top of the valve body (411); The upper cover (4134) is arranged at an end of the bellows housing (4131) that is away from the valve body (411); The adjusting bolt (4133) and the upper cover (4134) are threadedly connected, and the threaded end of the adjusting bolt (4133) passes through the upper cover (4134) and abuts against the top end of the adjusting structure (4132); an end of the adjusting structure (4132) away from the adjusting bolt (4133) is located in the inner cavity of the bellows housing (4131), and an end of the adjusting structure (4132) is connected to the valve core (412) to drive the valve core (412) to move up and down in the valve body (411); The valve core guide sleeve (4136) and the guide sleeve pressure ring (4137) are both sleeved on the valve core (412); The valve core guide sleeve (4136) is connected to the valve body (411) and is located at the top end of the valve body (411); a first through hole is formed on the valve core guide sleeve (4136); an input end of the first through hole is connected to an input end of the valve body (411), and an output end of the first through hole is connected to an inner cavity of the bellows housing (4131); The guide sleeve pressure ring (4137) is located in the inner cavity of the bellows housing (4131), one end of the guide sleeve pressure ring (4137) abuts against the valve core guide sleeve (4136), and the other end abuts against the adjustment structure (4132); The upper cover (4134) is provided with a pressure inlet, and the pressure inlet is connected to the inner cavity of the regulating structure (4132).

2. The constant pressure difference regulation system according to claim 1, characterized in that: The differential pressure regulating circuit (4) further comprises a back pressure valve (46); The input end of the back pressure valve (46) is connected to the output end of the second valve (45), and the output end of the back pressure valve (46) is connected to the oil tank (5).

3. The constant pressure difference regulation system according to claim 1, characterized in that: The power source circuit (1) comprises a coarse filter (11), a positive displacement pump (12) and a one-way valve (13); The input end of the coarse filter (11) is connected to the oil tank (5), and the output end is connected to the input end of the positive displacement pump (12); The output end of the positive displacement pump (12) is connected to the input end of the one-way valve (13), and the output end of the one-way valve (13) is connected to the input end of the inlet sealing loop (2).

4. The constant pressure difference regulating system according to claim 3, characterized in that: The power source circuit (1) further comprises a relief valve (14); The input end of the overflow valve (14) is connected between the output end of the volumetric pump (12) and the input end of the one-way valve (13), and the output end of the overflow valve (14) is connected to the oil tank (5).

5. The constant pressure difference regulating system according to claim 1, characterized in that: The inlet sealing circuit (2) comprises a high-precision filter (21), a bladder accumulator (22), a differential pressure transmitter (23) and an electromagnetic flowmeter (24); The input end of the high-precision filter (21) is connected to the output end of the power source circuit (1), and the output end is connected to the input end of the electromagnetic flowmeter (24); The output end of the electromagnetic flowmeter (24) is connected to the input end of the mechanical seal (6); The differential pressure transmitter (23) and the high-precision filter (21) are connected in parallel; The bladder accumulator (22) is connected between the output end of the power source circuit (1) and the input end of the high-precision filter (21).

6. The constant pressure difference regulating system according to claim 1, characterized in that: The outlet sealing circuit (3) comprises a flow regulating valve (31) and a heat exchanger (32); The input end of the flow control valve (31) is connected to the output end of the mechanical seal (6), and the output end is connected to the input end of the heat exchanger (32); The output end of the heat exchanger (32) is connected to the oil tank (5).

7. The constant pressure difference regulating system according to claim 1, characterized in that: It also includes a pressure-maintaining branch (7); The pressure-maintaining branch (7) comprises a first hydraulically controlled one-way valve (71) and a second hydraulically controlled one-way valve (72); The input end of the first hydraulically controlled one-way valve (71) is connected to the output end of the inlet sealing circuit (2), and the output end is connected to the input end of the mechanical seal (6); The input end of the second hydraulically controlled one-way valve (72) is connected to the output end of the mechanical seal (6), and the output end is connected to the input end of the outlet sealing circuit (3).

8. The constant pressure difference regulating system according to claim 1, characterized in that: The adjustment structure (4132) comprises a bellows positioning seat (41321), a bellows assembly (41322), a balance spring (41323), a balance spring pressure ring (41324) and a travel limit rod (41325); The bellows positioning seat (41321) is installed in the inner cavity of the bellows housing (4131) and is located at the bottom end of the bellows housing (4131); One end of the bellows assembly (41322) is connected between the bellows housing (4131) and the upper cover (4134), and the other end extends into the bellows housing (4131) and is connected to the valve core (412); The balance spring (41323) is arranged in the inner cavity of the bellows assembly (41322), one end of the balance spring (41323) is connected to the bottom end of the bellows assembly (41322), and the other end is connected to the balance spring compression ring (41324); One end of the balancing spring pressure ring (41324) that faces away from the balancing spring (41323) abuts against the threaded end of the adjusting bolt (4133); One end of the travel limit rod (41325) is connected to the balance spring compression ring (41324), and the other end is located in the balance spring (41323).

9. The constant pressure difference regulating system according to claim 1, characterized in that: The adjustment mechanism (413) further comprises an adjustment rod cover (4138); The adjusting rod cover (4138) is connected to an end of the upper cover (4134) that is away from the adjusting structure (4132); The head of the adjusting bolt (4133) is located in the inner cavity of the adjusting rod cover (4138).

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