Pressure gauge

Abstract

The invention relates to the technical field of fluid pressure measurement, in particular to a pressure gauge which is mainly used for measuring fluid pressure in the working condition of fluid media containing impurities and comprises a fluid introduction channel, a filtering cavity, a hollow filtering barrel, a measuring connector, a spring pipe and a pressure relief pipeline. The filter chamber is arranged in the introduction passage, and the inlet side is divided into the inner space and the outer space by the hollow filter barrel, so that the measured fluid is treated by the filter pores before entering the measurement side, and the filtered medium entering the spring tube is ensured; and meanwhile, a pressure relief pipeline which penetrates through the outer space and is directly communicated with the inner space is arranged to form an independent discharge passage. When the valve is opened, the measuring interface does not need to be closed, the pressure at the inlet side and the low pressure at the discharge end jointly establish an acting pressure difference, directional cleaning and discharge are formed in the internal space, and deposition is discharged along with the discharge passage without passing through the measuring side flow channel. The disturbance to the indicating mechanism in the cleaning process is reduced, and the upper pressure and the pressure relief of the reading are dynamically kept more consistent.

Description

Technical Field

[0001] This invention relates to the field of fluid pressure measurement technology, and more specifically to a pressure gauge. Background Technology

[0002] In applications involving fluids containing impurities, such as petrochemicals, water treatment, slurry transportation, hydraulics, and metallurgical cooling, pointer-type pressure gauges are commonly used for on-site monitoring. These gauges typically connect to the process piping via a measuring interface and are driven by a Bourdon tube through a connector cavity. To reduce the impact of pulsation and contaminants on the Bourdon tube, engineering practices often incorporate necked micropores, dampers, or sintered / wire mesh filter elements. Pre-filters are also sometimes installed on the process side, supplemented by manual bleed discharge using a three-way valve when necessary. However, these combinations often exhibit common problems during long-term operation: particle deposition at the micropores or filter layer on the flow-facing side gradually compacts, slowing the dynamic response during pressure increase / decrease and causing reading lag; the bleed discharge path and measuring path are often coupled, easily carrying impurities into the pressure-bearing area of ​​the gauge or pushing them back to the process side, causing secondary contamination and maintenance risks; while necking and flow restriction can suppress pulsation, it further reduces the ability to follow transient pressure changes, resulting in poor response consistency.

[0003] At the operation and maintenance level, relying on disassembly and cleaning or temporary venting from the process inlet usually requires shutdown or bypass switching, and the cleaning action is not easily aligned with the deposition interface, with residual areas becoming the starting point for subsequent blockages. Venting methods triggered by time or manually are not highly correlated with the actual dynamic state of the meter cavity, making it difficult to respond promptly to slowing indicators. Under different installation postures, the spatial relationship between the connector cavity and the discharge port changes with site constraints, resulting in unstable discharge paths and incomplete venting being common. In summary, under online measurement conditions containing impurities, existing technologies still struggle to balance anti-clogging capabilities, dynamic consistency of indications, and the feasibility of non-shutdown maintenance; long-term operational reliability and maintenance costs still have room for improvement. Summary of the Invention

[0004] (I) The technical problem to be solved by this invention is that, under online measurement conditions containing impurities, existing pressure gauges are prone to deposits at the inlet of the connector, resulting in a slower dynamic response to pressure increase / decrease. At the same time, the sludge discharge path is often coupled with the measurement path, and impurities can easily enter the Bourdon tube channel or be pushed back to the process side. Maintenance often relies on shutdown for disassembly and cleaning, making it difficult to remove deposits in a timely and targeted manner. Therefore, under the constraints of continuous pipeline flow and continuous equipment operation, the existing structure is unable to form a controlled and separated fluid space before and after filtration to organize the flow of the medium, and it is also difficult to provide an independent and controllable discharge path for inlet-side deposits without interfering with the measurement path, thus making it difficult to maintain consistent indication and operational reliability.

[0005] (II) Technical Solution To solve the above-mentioned technical problems, the present invention provides a pressure gauge, which is mainly used to measure the pressure of fluids in working conditions containing impurities, such as petrochemical, water treatment, slurry transportation, hydraulic and metallurgical cooling processes. The gauge includes a fluid inlet passage, a filter chamber, a hollow filter barrel, a measuring interface, a Bourdon tube and a pressure relief pipeline. The filter chamber is disposed in the inlet passage; The hollow filter barrel is disposed in the filter chamber, forming an internal space, and together with the filter chamber, defines an outer space. The internal space is fluidly connected to the outer space through the filter pores of the hollow filter barrel. The measurement interface is located at the beginning of the inlet passage and is used to establish fluid communication between the container or pipeline carrying the fluid to be measured and the internal space. The spring tube is disposed at the end of the inlet passage. The fixed end of the spring tube is connected to the outer space through a connecting pipe. The free end of the spring tube is closed and connected to the indicating mechanism through a linkage mechanism. The pressure relief pipeline is configured to pass through the outer space and directly connect with the inner space, and is used to lead the fluid in the inner space to the outside of the filter chamber. The exposed end of the pressure relief pipeline is equipped with a valve. When the valve is open, there is no need to close the measuring interface. The pressure difference between the inlet process pressure and the low pressure at the outlet end is used to perform tangential flushing and backwashing on the hollow filter barrel and to discharge the deposits in an organized manner.

[0006] By setting up a filter chamber in the inlet passage and using a hollow filter barrel to divide the inlet side into an internal space and an outer space, the measured fluid must undergo porous filtration before entering the measuring side, reducing the probability of particles directly entering the Bourdon tube and maintaining the cleanliness and stability of the pressurized medium of the indicating mechanism; the measuring interface is directly connected to the internal space, establishing a single pressurized link in the sequence of "container or pipeline, internal space, filter pores, outer space, connecting pipeline, Bourdon tube", reducing the interference of bypass and turbulence on the pressure / relief dynamics, and helping to maintain reading consistency; the pressure relief pipeline passes through the outer space and is directly connected to the internal space, and A valve is installed at its exposed end to form an independent discharge path decoupled from the measurement side. When opened, the medium containing impurities on the inlet side can be systematically led out to the outside of the filter chamber, avoiding backflow to the process side or entry into the Bourdon tube. The fixed end of the Bourdon tube is connected to the outer space, while the free end is closed and drives the indicating mechanism through a linkage mechanism. The pressure path on the measurement side is clear, and the impact of discharge operation on the mechanism and indicating transmission is reduced, which is conducive to long-term stable indication. All of the above structures are integrated into the inlet passage and connector area, with a compact layout and clear sealing boundaries, which facilitates cleaning and external discharge during operation, reducing the frequency of downtime maintenance and operation and maintenance costs.

[0007] According to one embodiment of the present invention, the valve is a solenoid valve; The pressure gauge also includes a detection device and a control device. The detection device is configured to acquire a detection signal characterizing the pressure state of the indicating mechanism and generate a rate of change parameter reflecting the pressure state over time. The control device is electrically connected to the detection device and the solenoid valve respectively, and is configured to control the solenoid valve to switch from closed to open when the rate of change parameter is lower than a preset threshold and the threshold condition is continuously met within a preset time window.

[0008] The detection device acquires signals corresponding to the pressure state of the indicating mechanism and calculates the rate of change parameter, directly reflecting the decrease in the flow capacity of the filter surface under different set points and fluctuating operating conditions. Using the rate of change as a criterion and setting thresholds and time windows, false triggering caused by instantaneous pulsations and measurement noise can be suppressed, initiating cleaning only when the dynamic response continuously slows down. The control device drives the solenoid valve to open rapidly, forming a discharge process with controllable duration and frequency; combined with a strategy of minimum interval time and cumulative opening limit, media loss caused by over-cleaning can be avoided. This closed loop matches the cleaning timing with the dynamics of the chamber, reducing the risk of premature or missed cleaning due to human judgment bias, alleviating maintenance burden, and maintaining the consistency of pressure increase and decrease response and reading stability during long-term operation.

[0009] According to one embodiment of the present invention, the spring tube extends in the opposite direction of gravity from its position of communication with the outer space, and the pressure relief line extends in the direction of gravity from its position of communication with the inner space to an exposed end, and is configured to form a liquid level difference between the communication passage between the outer space and the spring tube and the discharge passage from the inner space to the exposed end via the pressure relief line when the valve is opened.

[0010] The connection between the Bourdon tube and the outer space extends upwards, while the connection between the pressure relief line and the internal space extends downwards to the exposed end, creating a stable liquid level difference between the two passages when the valve is opened. This liquid level difference provides additional driving force at the moment of opening, causing the fluid in the internal space to preferentially flow out in the direction of pressure relief, thereby enhancing the initial cleaning and removal of deposits. Compared to methods that rely solely on pipeline pressure differentials, this arrangement can still achieve repeatable cleaning start-up conditions even when system pressure fluctuates or the pressure differential is small, shortening the start-up time and reducing the discharge volume required to achieve the same cleaning effect. The measuring side is located at a high position, and the discharge side is located at a low position, with a clear division of functions in the passages, reducing disturbances to the pressure state of the Bourdon tube during the cleaning process and helping to maintain dynamic consistency of the indication. Since the exposed end is at a low position and has an independent discharge path, the discharge direction is clear, reducing the possibility of backflow and secondary contamination, and improving the stability and maintainability of long-term operation.

[0011] According to one embodiment of the present invention, the exposed end of the pressure relief pipeline is connected to a negative pressure assembly, the negative pressure assembly includes a negative pressure chamber communicating with the pressure relief pipeline and a negative pressure component cooperating with the negative pressure chamber, the negative pressure component and the negative pressure chamber forming a variable volume space; The negative pressure chamber is provided with a vent and a vent switch for opening or closing the vent; The control device is configured to, when the rate of change parameter is lower than a preset threshold and the threshold condition is continuously met within a preset time window, first drive the negative pressure component to increase the variable volume space to form a low-pressure state in the negative pressure chamber, and then control the solenoid valve to switch from closed to open.

[0012] A negative pressure component is installed at the exposed end of the pressure relief pipeline. Centered on the variable volume space enclosed by the negative pressure component and the negative pressure chamber, the control device first drives the negative pressure component to increase its volume, creating a low-pressure state within the chamber. Then, the solenoid valve is switched to open. This sequence of low pressure followed by opening creates a larger initial pressure differential at the moment the valve opens, increasing the initial flow velocity in the direction of pressure relief within the internal space. This makes it easier for deposits to be stripped and carried away by the flow. Compared to cleaning methods that rely solely on pipeline pressure differentials, this solution is less sensitive to system pressure fluctuations and can reliably achieve repeatable startup effects even in low-pressure or insufficient pressure differential scenarios. Furthermore, the controllability of the negative pressure component's stroke and speed allows for the shaping of the pressure differential-time curve as needed, shortening the startup time and reducing the emissions required to achieve the same cleaning intensity. The vent in the negative pressure chamber is controlled by a vent switch, which can orderly discharge residual liquid in the chamber after the cleaning stage, avoiding residual liquid retention that may affect the establishment of negative pressure in subsequent stages. The component is located at the exposed end of the pipeline, which facilitates sealing, isolation and maintenance, does not interfere with the pressure path on the measurement side, and is conducive to the consistency and reliability of long-term operation.

[0013] According to one embodiment of the present invention, the negative pressure chamber is arranged vertically; The negative pressure component includes a plunger that slides and seals with the negative pressure cavity and is driven by a drive mechanism to reciprocate along the axis of the negative pressure cavity; The vent includes a first outlet located in the lower region of the sidewall of the negative pressure chamber; The drain switch includes a first drain switch for opening or closing the first outlet; The control device is configured to control the solenoid valve to switch from closed to open when the low pressure formed in the negative pressure chamber reaches a preset threshold. After the solenoid valve is opened, it continuously drives the plunger to move in the direction that increases the variable volume space to maintain the low pressure state until the sealing part of the plunger passes the position of the first outlet. After passing the outlet, it controls the first bleed switch to open so that the first outlet is connected to the negative pressure chamber.

[0014] The negative pressure chamber is vertically positioned, and the plunger, which slides and seals the chamber, reciprocates axially. This allows for stable formation and precise control of the chamber's volume changes, resulting in repeatable low-pressure establishment and maintenance. The vertical arrangement facilitates gas-liquid stratification and sediment deposition, reduces gas plug interference and lateral friction, and improves the continuity of the plunger seal and low-pressure stability. The first outlet is located at the lower part of the side wall and is controlled by a first venting switch. Only after the low pressure within the chamber reaches a threshold and the solenoid valve is open does the plunger continue to move in the direction of increasing volume to maintain the low pressure until its sealing part passes the first outlet, at which point the first venting switch is activated. This timing prevents premature venting before the low pressure is established or needs to be maintained, thus ensuring sufficient initial and sustained pressure differential. Simultaneously, the lower-positioned first outlet facilitates the priority discharge of liquid and solid particles accumulated at the bottom, shortening discharge time and reducing residue. Overall, the low-pressure setup and maintenance of the vertical plunger, in conjunction with the lower section venting, enhances the initial driving force and sustainability of the backwash process, reduces the opening time and discharge volume required to achieve the same level of cleanliness, and maintains consistency across multiple cycles.

[0015] According to one embodiment of the present invention, the drain port further includes a second outlet disposed in the upper region of the sidewall of the negative pressure chamber; The bleed switch includes a second bleed switch for opening or closing the second outlet; The control device is configured to control the solenoid valve to switch from open to closed before the plunger return stroke begins, to keep the second outlet open during the plunger return stroke in the direction that reduces the variable volume space to discharge residual fluid in the negative pressure chamber, and to close the second outlet at the end of the plunger return stroke.

[0016] A second outlet is installed on the upper part of the sidewall of the negative pressure chamber. Before the plunger returns, the solenoid valve is switched from open to closed to preemptively cut off the connection with the measured medium side, preventing pressure rise or backflow during the return stroke from affecting the measurement path. Subsequently, during the plunger's return stroke in the direction of reducing the variable volume space, the second outlet is opened, allowing residual liquid and gas accumulated in the upper part of the chamber to be quickly discharged through this high-level passage, reducing return resistance and internal compression effect, and preventing undischarged fluid from being squeezed into the internal space or the measurement side. At the end of the return stroke, the second outlet is closed, restoring the chamber to a sealed state and providing stable initial conditions for establishing low pressure for the next cycle. This coordination of position and timing decouples the reset process from the measurement path, reduces secondary contamination and indication disturbance, speeds up the turnaround time, and improves consistency and reliability across multiple cycles.

[0017] According to one embodiment of the present invention, the hollow filter barrel is arranged laterally within the filter chamber; The connection point between the pressure relief pipe and the internal space is located in the middle region of the hollow filter barrel.

[0018] The hollow filter barrel is horizontally arranged within the filter chamber, with the pressure relief pipe connecting to the internal space positioned in the middle region of the barrel wall. This allows the cleaning fluid to be distributed from the middle section of the barrel to both ends. This geometric relationship creates an approximately symmetrical pressure differential distribution between the front and rear sections, reducing the cleaning bias caused by preferential action on one side and promoting the simultaneous loosening and discharge of deposits at both ends. Simultaneously, the flow intake in the middle section shortens the path difference to both ends, reducing localized weak zones caused by uneven friction loss and facilitating a more balanced scouring effect in the circumferential direction. The horizontal arrangement makes the stress and sealing support of the barrel and filter chamber more balanced, reducing the off-center load and wear on the end seals, resulting in better cleaning consistency during long-term operation and more stable dynamic measurements after recovery.

[0019] According to one embodiment of the present invention, the hollow filter barrel is divided into a first cylindrical section and a second cylindrical section that are spaced apart from each other along its axial direction, and an annular member is provided between the first cylindrical section and the second cylindrical section; The annular component is fitted onto the central region of the hollow filter barrel and forms an enclosed annular connecting cavity, which is fixedly connected to the pressure relief pipeline. The ends of the first cylindrical section and the second cylindrical section facing the annular member are respectively rotate-sealed with the annular member; The pressure gauge also includes a rotating mechanism for driving the first and second cylindrical sections to rotate circumferentially relative to the annular member about their axes.

[0020] The hollow filter barrel is divided into two sections along the axial direction, with a fixed annular component in the middle forming an annular connecting cavity. This cavity is fixedly connected to the pressure relief pipeline, constituting a stable intake and discharge collection area. The two sections of the barrel are rotary sealed relative to the annular component and are driven by a rotating mechanism to rotate circumferentially around their own axis. This allows the filter pores at any circumferential position to pass through the high-efficiency cleaning zone opposite the annular connecting cavity during the operating cycle. Thus, the cleaning effect is no longer limited by a static orientation, circumferential dead angles are eliminated, and the accelerated deposition caused by prolonged local pressure or retention is significantly suppressed. The annular connecting cavity, as a fixed collection cavity, can maintain essentially constant intake conditions and discharge resistance during rotation, reducing fluctuations in cleaning intensity caused by angle changes. The two-section structure, supported by the rotary seal, distributes the cleaning load axially, reducing the off-center load and wear on the single-end seal and support. According to one embodiment of the present invention, a plurality of connecting rods are provided between the first cylindrical section and the second cylindrical section, and the two ends of the connecting rods are respectively fixedly connected to the first cylindrical section and the second cylindrical section to form a torque transmission part and make the two cylindrical sections rotate relative to the annular member as a whole. A communication hole is defined between the outer periphery of the connecting rod and the inner wall of the annular member, the communication hole allowing fluid communication between the internal space of the hollow filter barrel and the annular communication cavity; Multiple connecting rods extend axially along the hollow filter barrel and are spaced apart in its circumferential direction to form multiple communicating holes.

[0021] Multiple connecting rods are installed between the first and second cylindrical sections, with their ends fixed to the two sections respectively, forming a rigid torque transmission section. This allows the two cylindrical sections to rotate synchronously relative to the annular component as a single unit. Therefore, only one rotating mechanism is needed to drive both sections, resulting in a shorter transmission chain, fewer components, and simpler control, reducing uneven cleaning and seal wear caused by phase differences. The connecting rods are arranged axially and spaced circumferentially, helping to maintain the coaxiality and structural rigidity of the two cylindrical sections, stabilizing the linear pressure and contact state of the rotary seal, and reducing vibration and off-center loads. The connecting holes defined between the outer circumference of the connecting rods and the inner wall of the annular component form multiple parallel channels in the circumferential direction, ensuring continuous communication between the internal space and the annular connecting cavity at any angle, reducing flow path interruptions caused by local obstruction.

[0022] According to one embodiment of the present invention, the measuring interface includes a fixed section and a rotating section arranged coaxially, a rotary sealing structure is provided between the fixed section and the rotating section, and an annular seal is provided at the point where the rotating section passes through the wall of the filter chamber to maintain a fluid seal between the filter chamber and the measuring interface; The rotating section is fixedly connected to the first cylindrical section and rotates together, and at least a portion of it extends out of the filter chamber; The fixed section is used to connect with a container or pipeline that carries the fluid being measured; The rotating mechanism is located outside the filter chamber and is connected to the extended portion of the rotating section for transmission, so as to drive the first cylindrical section and the second cylindrical section to rotate around the axis of the hollow filter barrel.

[0023] The measurement interface employs a coaxial fixed section and a rotating section, with a rotary seal between them. The rotating section features an annular seal where it passes through the filter chamber wall, forming a continuous sealing boundary from the inside out. This double seal effectively isolates the medium from the external environment and confines the rotating pair to a controllable position, reducing the number of dynamic seals and the pressure-bearing area on the medium side, thus lowering the risk of long-term leakage and wear. The rotating section is fixedly connected to the first cylindrical section and rotates integrally, partially extending out of the filter chamber, allowing the rotating mechanism to be completely located outside the chamber. Transmission coupling is achieved through the extended section. This external drive avoids direct contact between the motor or transmission components and the medium, reducing the probability of failure caused by liquid intrusion, solid particle abrasion, and chemical corrosion. It also prevents the drive components from introducing heat or debris to the medium side.

[0024] The fixed section is specifically designed for connection with process vessels or pipelines. Its structure does not participate in rotation, ensuring stable stress and sealing at the process connection point, without introducing additional loads or fretting due to driving motion. The rotating mechanism is located outside the cavity, eliminating the need to disassemble the medium-side seal for inspection and replacement, simplifying the maintenance process and reducing downtime and media loss. Since the driving torque is transmitted to the two cylinder sections through the rigid rotating section, rotational coaxiality and angle control are easier to ensure, and the rotating seal is uniformly loaded. Combined with the aforementioned annular connection structure, this helps maintain the uniformity and repeatability of cleaning intensity, while reducing disturbance to the pressure path on the measurement side, improving the dynamic consistency and long-term reliability of the readings.

[0025] (III) Beneficial Effects of the Invention: This application, by setting a filter chamber in the inlet passage and dividing the inlet side into an inner space and an outer space with a hollow filter barrel, ensures that the fluid being measured is treated by the filter pores before entering the measuring side, guaranteeing that the medium entering the spring tube is filtered. Simultaneously, a pressure relief pipeline is arranged that passes through the outer space and directly communicates with the inner space, and the valve is placed at the exposed end to form an independent discharge passage. When the valve is opened, there is no need to close the measuring interface. The process pressure on the inlet side and the low pressure at the discharge end jointly establish a pressure difference, preferentially forming directional cleaning and discharge on the inner space side. Deposits are discharged in an organized manner along the discharge passage without passing through the measuring side flow channel. Since the measuring side is only connected to the spring tube through the connecting pipeline in the outer space, the discharge and measurement are physically decoupled in terms of space and communication. The disturbance of the pressure state of the indicating mechanism during the cleaning process is reduced, and the pressure readings and pressure relief dynamics remain more consistent. The aforementioned structure is concentrated in the joint area, with clear boundaries and simplified sealing. The valve components are located at the exposed end, which facilitates the use of standard parts and external control. Maintenance and discharge can be carried out without stopping the machine, reducing the frequency of disassembly and assembly and operation and maintenance costs, and improving the long-term stability and reliability of pressure measurement under conditions containing impurities. Attached Figure Description

[0026] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0027] Figure 1 This is a three-dimensional structural diagram of a pressure gauge provided in one embodiment of the present invention; Figure 2 This is a schematic diagram of the internal three-dimensional structure of the pressure system provided in one embodiment of the present invention; Figure 3 This is a three-dimensional schematic diagram of a partially cut interior of a pressure gauge according to an embodiment of the present invention; Figure 4This is a three-dimensional structural diagram of a pressure gauge with partially cut internally, according to an embodiment of the present invention.

[0028] Icons: 1. Filter chamber; 2. Hollow filter barrel; 21. Filter pores; 22. Ring-shaped component; 23. First cylindrical section; 24. Second cylindrical section; 25. Connecting rod; 26. Connecting hole; 3. Measuring interface; 31. Fixed section; 32. Rotating section; 33. Rotary sealing structure; 34. Annular seal; 4. Bourdon tube; 5. Pressure relief pipeline; 51. Valve; 6. Negative pressure assembly; 61. Negative pressure chamber; 611. First outlet; 612. First bleed switch; 613. Second outlet; 614. Second bleed switch; 62. Negative pressure component; 621. Plunger; 622. Drive mechanism; 7. Rotating mechanism; 101. Linkage mechanism; 102. Indicating mechanism; 103. Housing; 104. Dial. Detailed Implementation

[0029] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Specific Implementation

[0030] like Figures 1 to 4 As shown, this embodiment provides a pressure gauge, which is mainly used to measure the pressure of fluids in working conditions containing impurities, such as petrochemical, water treatment, slurry transportation, hydraulic and metallurgical cooling processes. It mainly includes a fluid inlet passage, a filter chamber 1, a hollow filter barrel 2, a measuring interface 3, a spring tube 4, a pressure relief pipeline 5, and a negative pressure component 6.

[0031] The pressure gauge, within its housing 103, sequentially arranges a measuring interface 3, a filter chamber 1, and a connecting pipe along the inlet path. The connecting pipe guides the medium into a Bourdon tube 4, driving a linkage mechanism 101 to activate an indicating mechanism 102, which displays the pressure on the dial 104. Specifically, the measuring interface 3 introduces the process-side medium into a hollow filter barrel 2 within the filter chamber 1. The medium first enters the inner region of the hollow filter barrel 2, then flows through the filter pores 21 on its wall to the annular flow channel between the hollow filter barrel 2 and the filter chamber 1. Subsequently, it enters the Bourdon tube 4 through the connecting pipe and expands under pressure. The elastic deformation of the Bourdon tube 4 is transmitted and amplified by the linkage mechanism 101 into the angular displacement of the indicating mechanism 102, thus forming a readable pressure indication on the dial 104. This flow channel relationship structurally sequences the introduction, filtration, and measurement of the medium. The medium undergoes separation through the filter pores 21 before reaching the Bourdon tube 4. The pressure path on the measuring side is clear and physically separated from the filtration location, which helps reduce the impact of deposition on the dynamic characteristics of the indicating mechanism 102.

[0032] like Figure 4 As shown, the filter chamber 1 is a horizontally arranged cylindrical chamber located in the middle of the inlet passage. It is preferably integrally formed with the shell 103 or fitted with a cylindrical stop and axially sealed with an end-face sealing strip. Its inner wall has a positioning shoulder based on a coaxial cylindrical surface, serving as a reference surface for coaxial assembly with the hollow filter barrel 2. Both ends of the chamber are connected to the inner cavity channel on the side of the measuring interface 3 and the inner cavity channel on the side of the connecting pipe, respectively, allowing the medium to form a path of axial entry, radial permeation, and then axial convergence within the chamber. The cylindrical surface of the chamber is fitted with the outer circle of the hollow filter barrel 2 with an annular gap, which is continuous in the circumferential direction, forming an annular flow channel in the outer space.

[0033] The hollow filter barrel 2 is a thin-walled cylindrical component, arranged laterally and coaxial with the filter chamber 1. A uniform circumferential annular gap is maintained between its outer circumference and the inner wall of the filter chamber 1 to define the outer space, while the inside of the barrel is a hollow cavity serving as the internal space. Both end faces engage with positioning shoulders at the ends of the filter chamber 1 to determine the axial position. The cylindrical wall of the hollow filter barrel 2 forms filter pores 21, which can adopt three equivalent configurations: through-hole type, longitudinal slit type, or multi-layered permeable type. The through-hole type arranges micropores on the cylindrical wall at equal circumferential intervals and staggered axial rows and columns; the longitudinal slit type sets parallel slits with the axial direction as the main direction and distributes them at intervals circumferentially; the multi-layered permeable type lays a porous layer on the outside or inside of the load-bearing base cylinder and overlaps with the through holes of the base cylinder to form a gradually changing pore channel. The above configuration forms an infiltration channel from the inside out within the thickness of the cylinder wall. The pore edges can be blunted to reduce burr residue. The pore distribution can be divided into circumferentially equidistant or axially strip-shaped sections to adapt to different deposition morphologies. The connection between the pressure relief pipe 5 and the internal space is arranged in the middle region of the hollow filter barrel 2. Preferably, it is connected to the end of the pressure relief pipe 5 by insertion or butt welding through a radially opened butt hole. The axis of the connection port points radially towards the center of the cylinder. The positioning reference is taken from the circumference of the middle region to control the relative positional relationship with the annular component 22 during assembly.

[0034] The hollow filter barrel 2 is divided into a first cylindrical section 23 and a second cylindrical section 24, which are spaced apart from each other along its axial direction. An annular member 22 is provided between the two sections. The annular member 22 is fitted in the middle area and forms an annular connecting cavity with the ends of the two cylindrical sections. The annular connecting cavity forms a stable confluence area through a fixed connection with the pressure relief pipe 5. The outer circle of the annular member 22 can be set to maintain a gap or a slight interference static fit with the inner wall of the filter chamber 1 to achieve radial positioning. The ends of the first cylindrical section 23 and the second cylindrical section 24 facing the annular member 22 are respectively rotated and sealed with the annular member 22. The rotational sealing fit can adopt three equivalent forms: end face fit type, end face-step composite labyrinth type, or end face-conical transition type. The end face fit type forms a main sealing band by smooth contact of the two end faces; the end face-step composite labyrinth type sets one or more steps on the outer side of the end face to form an axial-radial deflection gap; the end face-conical transition type introduces a small-angle conical surface at the outer edge of the end face to form a gradually changing gap and take into account the end face positioning. The three forms can be selected by choice or combined according to process conditions. The roughness of the sealing surface and the runout of the end face are controlled by grinding and polishing and assembly reference to limit the leakage channels during rotation.

[0035] The rotating mechanism 7 is connected to the end connecting components of the first cylindrical section 23 and the second cylindrical section 24, enabling the two cylindrical sections to rotate circumferentially relative to the annular member 22 around their axes. The connecting parts can be provided with splined surfaces, flat keyways, or clamping cylindrical surfaces at the ends of the cylindrical sections to achieve torque input and coaxial constraint. The connecting length is selected based on a range not less than the effective wall thickness at the ends of the cylindrical sections to balance force transmission stability and assembly accessibility. After assembly, the annular member 22 remains stationary. Driven by the rotating mechanism 7, the two cylindrical sections rotate relative to each other using the inner hole and end face of the annular member 22 as guide surfaces, thereby maintaining a coaxial and end-face mating state within the rotary sealing mating area.

[0036] Multiple connecting rods 25 are installed between the first cylindrical section 23 and the second cylindrical section 24. The two ends of each connecting rod 25 are fixedly connected to the end reinforcement areas of the two cylindrical sections to form a torque transmission section, allowing the two cylindrical sections to rotate as a single unit relative to the annular member 22 when the rotating mechanism 7 is loaded. The axes of the connecting rods 25 are parallel to the axis of the hollow filter barrel 2 and are arranged at equal angular intervals in the circumferential direction. A connecting hole 26 is naturally defined between the outer periphery of the connecting rod 25 and the inner wall of the annular member 22. The connecting holes 26 are spaced apart circumferentially and axially connected, serving as a multi-channel passage between the internal space and the annular connecting cavity. The cross-sectional shape of the connecting rod 25 can be a circle, a rounded polygon, or a slender rectangle, etc., to meet the requirements for torque transmission and stiffness while forming the required cross-sectional area of ​​the connecting hole 26.

[0037] In this preferred embodiment, the Bourdon tube 4 is located at the end of the inlet passage and is fixed to the support of the housing 103 in an upwardly extending semi-annular cavity configuration. Its fixed end is pressurized through a passage connected to the outer space, and the free end is a closed end. The Bourdon tube 4 adopts an elliptical or approximately flattened elliptical thin-walled cross section, so that it produces a combined elastic deformation of the cross section tending to circle and circumferential expansion when compressed, thereby generating repeatable outward displacement in the plane. To ensure assembly coaxiality and repeatability, the fixed end is engaged with the reference surface of the housing 103 through a positioning shoulder, and the free end is located in the corresponding motion plane behind the dial 104 in the uncompressed state, forming a force transmission geometry relationship with the linkage mechanism 101. The transition joint between the Bourdon tube 4 and the outer space is preferably a rigid tube or an integral short-neck structure to reduce the length of the flexible section and improve the positional stability under pressure.

[0038] The linkage mechanism 101 is located in the motion plane of the free end of the Bourdon tube 4. Through a hinge link and equivalent transmission with a small gear sector, indexing gear, or eccentric link, the end displacement is converted into the angular displacement of the indicating mechanism 102. The pointer of the indicating mechanism 102 rotates around the central axis on the dial 104 to complete the reading display. To reduce hysteresis, the linkage mechanism 101 is equipped with an adjustable preload meshing or backlash compensation structure at the transmission pair, and the mechanical boundaries between zero position and full scale are limited by a limiting member. The relative position of the dial 104 and the pointer is calibrated with zero pressure during assembly, and the pointer bearing adopts a sliding or micro-rolling support to ensure the stability of rotational resistance.

[0039] The spring tube 4, starting from its connection point with the outer space, is arranged in the opposite direction of gravity to form a high-level pressurized passage. The pressure relief pipe 5, starting from its connection point with the internal space, extends in the direction of gravity to its exposed end to form a low-level discharge passage. When the valve 51 is opened, the geometric height difference between the two passages creates a liquid level difference within the already filled connected system. This, combined with the pressure exerted by the process side on the internal and outer spaces, provides additional drive for the volumetric flow directed towards the pressure relief pipe 5. This liquid level difference originates from the relative height relationship between the pressurized passage arranged in the opposite direction of gravity and the discharge passage arranged in the direction of gravity. Even when the pressure of the measured medium itself is low, it can still provide a considerable static pressure head contribution. If a continuously descending flow path is formed between the exposed end of the pressure relief pipe 5 and the connecting section of the internal space, a stable gravity-fed drainage can be established at the moment of opening, reducing dependence on system pressure differential. Since the spring tube 4 maintains continuous connection with the outer space, the pressure transmission path on the measuring side does not need to be switched, and the linkage mechanism 101 and the indicating mechanism 102 maintain normal pressure and indicating relationships during the cleaning process.

[0040] The pressure relief pipe 5 extends radially from the filter chamber 1, and its inner end is rigidly fixedly connected to the annular connecting cavity of the ring member 22. A butt weld or a detachable threaded-end-face seal fit is preferably used to ensure coaxiality and sealing. Where the pressure relief pipe 5 passes through the outer space, it forms a circumferential seal fit with the inner wall of the filter chamber 1, allowing it to pass through geometrically but not fluidly communicate with the outer space. The outer end of the pressure relief pipe 5 has a fixed connection area with the outer wall of the housing 103. This rigid connection simultaneously provides radial support to the ring member 22, thereby stabilizing the relative position of the ring member 22 and the hollow filter barrel 2. The axis of the pressure relief pipe 5 is preferably arranged radially at the ring member 22, facilitating linear or angular connection of its exposed end to external components.

[0041] A valve 51 is installed at the exposed end of the pressure relief pipeline 5. The valve 51 is preferably a solenoid valve and is directly connected to the pressure relief pipeline 5 or connected by a short section. The installation direction of the valve 51 is consistent with the axis of the pressure relief pipeline 5 to reduce local pressure loss and facilitate maintenance and disassembly. An operating clearance is left between the valve 51 and the housing 103. The electrical connectors and control lines are arranged along the outer surface of the housing 103 and do not intersect with the medium-side cavity.

[0042] The negative pressure assembly 6 is installed downstream of the valve 51 and connected to the pressure relief pipeline 5. The negative pressure chamber 61 is a long, narrow cylinder arranged vertically, with its axis aligned with the direction of gravity, so that the negative pressure assembly 62 can reciprocate axially. The negative pressure assembly 62 is a plunger 621, which forms a sliding seal with the inner wall of the negative pressure chamber 61. The plunger 621 rod is coupled to the drive mechanism 622 above or laterally in the negative pressure chamber 61. The drive mechanism 622 drives the plunger 621 to reciprocate axially to change the effective volume of the negative pressure chamber 61. The connection end between the negative pressure chamber 61 and the pressure relief pipeline 5 adopts a coaxial transition section, and the inner wall of the transition section smoothly transitions with the inner wall of the pressure relief pipeline 5 to avoid forming a step.

[0043] The vents are located on the side wall of the negative pressure chamber 61. The first outlet 611 is located in the lower region of the side wall and is opened and closed by the first vent switch 612. The second outlet 613 is located in the upper region of the side wall and is opened and closed by the second vent switch 614. The two vent switches are connected to the outer ends of the corresponding outlets by threaded seals or flange seals. The valve core type can be needle type, ball type, or slide valve type, etc., and the interface dimensions are the same as those of the pressure relief pipeline 5 or transitioned through a short connector. An annular flow band is maintained between the first outlet 611 and the bottom of the negative pressure chamber 61 to avoid interference between the outlet component and the plunger 621 at the lowest position.

[0044] The measuring interface 3 is connected to the process side at the beginning of the inlet passage. The fixed section 31 and the rotating section 32 are coaxially fitted together. The fixed section 31 serves as a carrier for docking with the process container or pipeline, and its inner cavity is connected to the inner cavity of the rotating section 32 to form a continuous medium channel. A rotary sealing structure 33 is provided between the two sections. The rotary sealing structure 33 preferably adopts an end face seal or an end face-radial composite seal. The fixed section 31 provides a sealing stationary ring reference, and the rotating section 32 provides a sealing dynamic ring reference. The sealing surfaces are kept in contact by axial preload or shoulder limiters to ensure axial sealing and coaxiality of the medium passage when the rotating section 32 rotates relative to the fixed section 31. An annular seal 34 is provided where the rotating section 32 passes through the wall of the filter chamber 1. The annular seal 34 is embedded in the annular sealing groove of the wall and forms a radial sealing contact with the outer circle of the rotating section 32. End face steps are provided on both sides of the sealing groove to control the compression and axial positioning, so that the filter chamber 1 and the measuring interface 3 maintain an independent fluid sealing boundary in the rotating state.

[0045] The rotating section 32 and the first cylindrical section 23 are rigidly connected and rotate as a single unit. The connection method can be an internal or external threaded butt joint, a splined insertion, or a keyed connection, etc. The connection part is provided with an end face stop or a round shoulder to achieve coaxial positioning and limit axial movement. In order to facilitate reliable transmission with the rotating mechanism 7, at least a part of the outer end of the rotating section 32 extends out of the filter chamber 1. The extended part is machined into a regular cylindrical shape or a transmission shape with a plane / spline, so as to allow the connecting parts to clamp or engage. The process connection end of the fixed section 31 uses standard interface forms such as threads, flanges, or ferrules with the container or pipeline. The fixed section 31 and the shell 103 are fitted with an end face seal and a positioning stop to ensure that the medium enters from the process side and is continuously introduced into the internal space of the hollow filter barrel 2 through the inner cavity of the fixed section 31 and the rotating section 32.

[0046] The rotating mechanism 7 is located outside the filter chamber 1 and is connected to the extended part of the rotating section 32. The transmission connection can be a clamping coupling, a key coupling, or a gear meshing, etc. The connection length covers the effective mating area of ​​the extended part of the rotating section 32 to ensure torque transmission and coaxial constraint. The output axis of the rotating mechanism 7 is aligned with the axis of the rotating section 32. The angular and axial positions are defined by the coaxial guidance of the connecting parts and the end face contact. The torque is transmitted to the first cylindrical section 23 through the rotating section 32, and the two sections rotate synchronously around the axis of the hollow filter barrel 2 through the connecting rod 25 between the first cylindrical section 23 and the second cylindrical section 24.

[0047] like Figure 2 As shown, the detection device takes the pressure state of the indicating mechanism 102 as the measured object. Preferably, it samples the angular displacement signal corresponding to the pressure from the linkage mechanism 101 or the indicating mechanism 102, or samples the strain or pressure signal corresponding to the pressure from the spring tube 4 and the outer space. Any of these signals is conditioned and converted into an electrical signal before being input to the control device. The detection device can employ one or more combinations of equivalent structures such as angle encoding, Hall magnetoresistive sensing, photoelectric sampling, strain bridge, or micro-pressure sampling to support sampling under different installation postures and media conditions. During assembly, the housing 103 or the bearing seat of the dial 104 is used as the installation reference to ensure a stable correspondence with the linkage mechanism 101 or the outer space. The control device uses the electrical signal as a time series, first completing zero-point and range mapping, filtering and denoising, then calculating the rate of change parameter over time, and internally retaining a time window buffer and threshold data for comparison. The threshold is determined by the cleanliness response curve obtained from the calibration and the dynamic coefficient of the field conditions. The range of values ​​is limited to the interval that can distinguish between normal fluctuations and blockage trends. The time window is used to confirm that the low rate of change is a continuous state rather than an instantaneous disturbance.

[0048] When the rate of change parameter is below the threshold and this condition is met continuously within the time window, the control device starts the cleaning process according to a predetermined sequence: First, the negative pressure component 62 is driven to move in the direction of increasing the variable volume space to establish low pressure in the negative pressure chamber 61. The stroke and speed of the negative pressure component 62 are output according to a preset curve. If necessary, the stroke is finely adjusted in combination with changes in the pressure state to ensure that the low pressure threshold for flow intake is reached before subsequent discharge is established. After the low pressure is established as expected, the control solenoid valve is switched from closed to open, and a rotation command is sent to the rotating mechanism 7 to make the first cylinder section 23 and the second cylinder section 24 rotate circumferentially around the axis of the hollow filter barrel 2. The angular velocity and angular stroke of the rotation are set according to the medium and deposition characteristics. A constant speed mode or a segmented mode can be selected. During the cleaning stage, the control device maintains the negative pressure component 62 to continue moving in the aforementioned direction to maintain the low pressure state in the negative pressure chamber 61 during the opening of the solenoid valve.

[0049] During the cleaning process, the control device monitors the position of the negative pressure component 62 relative to the negative pressure chamber 61. When the sealing part of the plunger 621 approaches the geometric position of the first outlet 611, the stroke speed is reduced to ensure the accuracy of the overshoot determination. After determining that its sealing part has overshot the first outlet 611, the first venting switch 612 is opened to connect the first outlet 611 with the negative pressure chamber 61 for segmented venting. Subsequently, the rotating mechanism 7 is maintained to complete the rotation sequence according to the set angle stroke, and the output of the rotating mechanism 7 is stopped after the set cleaning time or cleaning angle stroke is reached. Throughout the entire stage, the measurement interface 3 remains pressurized and connected to the outer space, and the sampling of the indicating mechanism 102 continues. The control device records the pressure dynamics before and after cleaning for subsequent threshold self-calibration or maintenance prompts.

[0050] During the reset process, before the plunger 621 begins its return stroke, the control device first switches the solenoid valve from open to closed, cutting off the connection between the internal space and the external discharge end. Then, it opens the second bleed switch 614, putting the second outlet 613 in the open state, and drives the plunger 621 to return in the direction of decreasing variable volume space to discharge residual fluid and accumulated gas in the negative pressure chamber 61. After the plunger 621 returns to its position, it closes the second bleed switch 614, restoring the seal of the negative pressure chamber 61. If necessary, the control device resets and closes the first bleed switch 612, and returns the rotating mechanism 7 to its initial angle or stops at its current position, depending on the preset strategy. At this point, the cleaning and reset process is complete. The detection device continues to monitor the pressure state. When the rate of change parameter returns to normal, the control device remains in standby mode until the next criterion is met before triggering again.

[0051] The above are preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made to the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A pressure gauge comprising an introduction passage for fluid, characterized by, Also comprising: a filter chamber arranged in the introduction passage; a hollow filter barrel arranged in the filter chamber, enclosing an inner space and jointly defining an outer space with the filter chamber, and the inner space being in fluid communication with the outer space through filter pores of the hollow filter barrel; a measurement interface arranged at a starting end of the introduction passage, for forming fluid communication between a container or pipeline carrying a fluid to be measured and the inner space; a spring tube arranged at an ending end of the introduction passage, a fixed end of the spring tube being in communication with the outer space through a communication pipeline, and a free end of the spring tube being closed and connected to an indicating mechanism through a linkage mechanism; a pressure relief pipeline arranged to pass through the outer space and directly communicate with the inner space, for leading fluid in the inner space out of the filter chamber, and an exposed end of the pressure relief pipeline being provided with a valve.

2. The pressure gauge according to claim 1, characterized in that The valve is an electromagnetic valve; The pressure gauge further comprises a detection device and a control device, the detection device being configured to obtain a detection signal for characterizing a pressure state of the indicating mechanism and generate a rate parameter reflecting a change of the pressure state over time; The control device is electrically connected with the detection device and the electromagnetic valve respectively, and is configured to control the electromagnetic valve to switch from closed to open when the rate parameter is below a preset threshold and continuously satisfies the threshold condition within a preset time window.

3. The pressure gauge of claim 2, wherein, The spring tube extends in a direction opposite to gravity from a position where it communicates with the outer space, and the pressure relief pipeline extends in a direction of gravity from a position where it communicates with the inner space to the exposed end, and is configured to form a liquid level difference between a communication passage of the outer space and the spring tube and a discharge passage of the inner space to the exposed end of the pressure relief pipeline when the valve is open.

4. The pressure gauge according to claim 3, wherein an exposed end of the pressure relief pipeline is connected with a negative pressure assembly, the negative pressure assembly comprising a negative pressure cavity in communication with the pressure relief pipeline and a negative pressure element cooperating with the negative pressure cavity, and the negative pressure element and the negative pressure cavity enclosing a variable volume space; the negative pressure cavity is provided with a discharge port and a discharge switch element for opening or closing the discharge port; the control device is configured to first drive the negative pressure element to increase the variable volume space to form a low pressure state in the negative pressure cavity, and then control the electromagnetic valve to switch from closed to open, when the rate parameter is below a preset threshold and continuously satisfies the threshold condition within a preset time window.

5. The pressure gauge according to claim 4, wherein the negative pressure cavity is arranged vertically; the negative pressure element comprises a plunger in sliding sealing cooperation with the negative pressure cavity and is driven by a driving mechanism to reciprocate along an axis of the negative pressure cavity; the discharge port comprises a first outlet arranged at a lower region of a side wall of the negative pressure cavity; the discharge switch element comprises a first discharge switch element for opening or closing the first outlet; The control device is configured to control the electromagnetic valve to switch from closed to open when the low pressure formed in the negative pressure cavity reaches a preset threshold, and to continuously drive the plunger to move in a direction to increase the variable volume space to maintain the low pressure state after the electromagnetic valve is opened until the sealing part of the plunger passes the position of the first outlet, and to control the first discharge switch to open after passing to make the first outlet communicate with the negative pressure cavity.

6. The pressure gauge according to claim 5, wherein, the discharge port further comprises a second outlet arranged at an upper region of the side wall of the negative pressure cavity; the discharge switch comprises a second discharge switch for opening or closing the second outlet; the control device is configured to control the electromagnetic valve to switch from open to closed before the plunger starts to return, and to keep the second outlet in an open state to discharge residual fluid in the negative pressure cavity during the return of the plunger in a direction to decrease the variable volume space, and to close the second outlet when the return of the plunger ends.

7. The pressure gauge according to any one of claims 1 to 6, wherein, the hollow filter barrel is arranged transversely in the filter chamber; the communication part of the pressure relief pipeline with the internal space is arranged at a middle region of the hollow filter barrel.

8. The pressure gauge according to claim 7, wherein, the hollow filter barrel is divided into a first barrel segment and a second barrel segment arranged at intervals along an axial direction thereof, and an annular member is arranged between the first barrel segment and the second barrel segment; the annular member is sleeved at a middle region of the hollow filter barrel and forms a closed annular communication cavity, and the annular communication cavity is fixedly communicated with the pressure relief pipeline; one end of each of the first barrel segment and the second barrel segment towards the annular member is in rotational sealing cooperation with the annular member; the pressure gauge further comprises a rotating mechanism for driving the first barrel segment and the second barrel segment to rotate circumferentially around the annular member.

9. The pressure gauge according to claim 8, wherein, a plurality of connecting rods are arranged between the first barrel segment and the second barrel segment, and two ends of each of the connecting rods are fixedly connected with the first barrel segment and the second barrel segment respectively to form a torque transmission part and make the two barrel segments rotate as an integral part relative to the annular member; an annular communication hole is defined between the outer periphery of the connecting rod and the inner wall of the annular member, and the annular communication hole makes the internal space of the hollow filter barrel and the annular communication cavity in fluid communication; the plurality of connecting rods extend along the axial direction of the hollow filter barrel and are arranged at intervals in the circumferential direction to form a plurality of annular communication holes.

10. The pressure gauge according to claim 9, wherein, the measurement interface comprises a fixed segment and a rotating segment arranged coaxially, a rotating sealing structure is arranged between the fixed segment and the rotating segment, and the rotating segment is provided with an annular sealing member at a position penetrating the wall of the filter chamber to keep the filter chamber and the measurement interface in fluid sealing; the rotating segment is fixedly connected with the first barrel segment and rotates integrally, and at least a part of the rotating segment extends out of the filter chamber. The fixed section is used to communicate with a container or pipeline carrying the fluid to be measured; The rotating mechanism is arranged outside the filtering chamber and is in transmission connection with the extended part of the rotating section, so as to drive the first cylinder section and the second cylinder section to rotate around the axis of the hollow filtering barrel.

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