Filter and filter element backwashing method thereof without stopping natural gas transportation and distribution filtration

Abstract

The invention belongs to the technical field of natural gas transportation and distribution filtration of natural gas stations, and relates to a filter and a filter element backwashing method thereof without stopping natural gas transportation and distribution filtration. The filter comprises a main cylinder, a main filter element and a backwashing device, wherein the backwashing device comprises an air blowing cylinder arranged in the main filter element, a high-pressure hose used for conveying high-pressure gas into the air blowing cylinder and a driving mechanism used for driving the air blowing cylinder to reciprocate in the main filter element in the axial direction; the air blowing cylinder is of a cylindrical structure with two closed ends, and a plurality of air blowing holes are formed in the side wall; the high-pressure hose is located in the main filter element, the bottom end of the high-pressure hose is connected to the top end of the air blowing cylinder, the top end of the high-pressure hose is externally connected with a high-pressure air supply source, and high-pressure air entering the air blowing cylinder is blown out through the air blowing holes to backwash the main filter element from inside to outside. The air blowing cylinder of the filter can perform movable backwashing in the main filter element, so that the whole main filter element is helped to recover the filtering effect, and the backwashing device can independently operate to backwash the main filter element while the filter continuously filters natural gas.

Description

Technical Field

[0001] The invention belongs to the technical field of natural gas station filtering equipment, and in particular relates to a natural gas transmission and distribution filter and a filter element backwashing method of the filter without stopping natural gas transmission and distribution filtering. Background Art

[0002] The filter is an important equipment in the process of natural gas transmission and distribution at natural gas stations. Its main principle is to use the filter element to filter out solid impurities in natural gas. Due to the accumulation of solid impurities, the filter element is easily blocked, which reduces the filtering efficiency and even damages the equipment. The conventional processing flow after the filter element of the filter is blocked is to shut down the machine and stop gas for maintenance, including checking the pressure difference, shutting down for isolation, replacing the filter element, cleaning the equipment and other steps. Shutting down the filter for gas maintenance will not only affect the gas supply, but also increase the workload of the operators. Therefore, how to maintain the filter element of the filter without stopping the transmission and distribution of natural gas is a major trend in technological development.

[0003] A title and abstract search was conducted on the public database of Chinese patents with the search formula "natural gas and filtration and blockage and cleaning". Patented technologies for cleaning filter elements by backwashing were found, such as a natural gas transmission and distribution filtration device proposed by announcement number CN118558056B. A title and abstract search was conducted again with the search formula "natural gas and filtration and backwashing". Patents such as announcement numbers CN117732181B, CN217410156U, and CN204411909U were found, all of which involve filter element backwashing technology. However, the above-mentioned existing patents involving filter element backwashing technology all require that the filter element backwashing can only be performed when the natural gas transmission and distribution filtration is stopped. Therefore, how to backwash the filter element without stopping the natural gas transmission and distribution filtration is still a technical problem that needs to be solved urgently. Summary of the invention

[0004] The present invention aims to provide a filter and a filter element backwashing method thereof without stopping natural gas transmission and distribution filtration, so as to solve the problem of how to backwash the filter element without stopping natural gas transmission and distribution filtration proposed in the above background technology.

[0005] The present invention is achieved through the following technical solutions: A filter comprises a main cylinder, a main filter element and a backwashing device; The main filter element is arranged inside the main cylinder body. A natural gas inlet pipe is provided on the top side wall of the main cylinder body, and a natural gas outlet pipe is provided at its bottom end. The natural gas inlet pipe is communicated with the annular space at the inner top of the main cylinder body, and the natural gas outlet pipe is communicated with the inner bottom of the main filter element. The natural gas containing solid impurities enters the inside of the main cylinder body through the natural gas inlet pipe. The natural gas can pass through the main filter element and enter it, while the solid impurities are blocked outside the main filter element by the main filter element. The natural gas in the main filter element is discharged through the natural gas outlet pipe to carry out natural gas transmission and distribution filtration. The backwashing device includes a blowing cylinder arranged inside the main filter element, a high-pressure hose for conveying high-pressure gas into the blowing cylinder, and a driving mechanism for driving the blowing cylinder to reciprocate axially inside the main filter element; the blowing cylinder is a cylindrical structure with both ends closed, and several blowing holes are opened on its side wall; the high-pressure hose is located inside the main filter element, its bottom end is connected to the top end of the blowing cylinder and is communicated with the inside of the blowing cylinder, and its top end is externally connected to a high-pressure gas supply source. High-pressure gas can be conveyed into the blowing cylinder through the high-pressure hose. The high-pressure gas inside the blowing cylinder is blown out through the blowing holes to impact the side wall of the main filter element. The high-pressure gas can pass through the side wall of the main filter element from the inside to the outside to blow off the solid impurities attached to the outer side wall of the main filter element, and perform backwashing on the main filter element from the inside to the outside; while the high-pressure gas in the blowing cylinder is blown out to backwash the main filter element, the driving mechanism can drive the blowing cylinder to reciprocate axially inside the main filter element. The blowing cylinder moves and backwashes the main filter element inside the main filter element at the same time, and can perform mobile backwashing inside the main filter element, and can backwash each section of the main filter element successively, which helps the entire main filter element to restore the filtering effect. While the filter continuously filters natural gas, the backwashing device can operate independently to backwash the main filter element.

[0006] Further, annular sealing rings for forming a seal with the inner side wall of the main filter element are fixed on both the top side wall and the bottom side wall of the blowing cylinder, so that the high-pressure gas blown out from the blowing holes on the side wall of the blowing cylinder impacts the side wall of the main filter element between the two annular sealing rings, and performs backwashing on the main filter element from the inside to the outside, reducing the leakage of the high-pressure gas blown out from the blowing holes to the main filter element above and below the blowing cylinder through the gap between the top of the blowing cylinder and the inner side wall of the main filter element or the gap between the bottom of the blowing cylinder and the inner side wall of the main filter element, so that more high-pressure gas can pass through the side wall of the main filter element from the inside to the outside to blow off the solid impurities attached to the outer side wall of the main filter element, and promote the restoration of the filtering effect of the part of the side wall of the main filter element that coincides with the blowing cylinder.

[0007] Further, the high-pressure hose is spiral. When the blowing cylinder reciprocates axially along the main filter element, the spiral high-pressure hose can stretch and contract accordingly, ensuring the supply of high-pressure backwashing gas inside the blowing cylinder.

[0008] Further, the driving mechanism includes a motor, a lead screw, and a guide rod. The motor is installed at the outer top of the main cylinder body. A coaxial internal threaded tube is fixed at the center of the air blowing cylinder. The lead screw passes through the internal threaded tube and is threadedly connected to the internal threaded tube. A guide tube is fixed on the air blowing cylinder, and the central axis of the guide tube is parallel to the central axis of the air blowing cylinder. The guide rod passes through the guide tube, and both ends of the guide rod are respectively connected to the top end and the bottom end of the main cylinder body. The bottom end of the lead screw is rotatably connected to the inner bottom of the main cylinder body. The top end of the lead screw passes through the top end of the main cylinder body and is rotationally and dynamically sealed with the top end of the main cylinder body through a seal. The top end of the lead screw is drivingly connected to the power output end of the motor. The motor is used to drive the lead screw to rotate to drive the air blowing cylinder to move axially inside the main filter element; the motor can drive the lead screw to rotate, the guide rod can limit the rotation of the air blowing cylinder, the motor is a forward and reverse rotation motor, the motor can drive the lead screw to rotate forward and reverse, and the lead screw can drive the air blowing cylinder to reciprocate axially.

[0009] Further, a ventilation pipe is fixed on the air blowing cylinder. Both ends of the ventilation pipe respectively pass through the top end and the bottom end of the air blowing cylinder. The ventilation pipe is used to connect the inside of the main filter element at the upper and lower ends of the air blowing cylinder, so that the natural gas that enters the inside through the side wall of the top of the main filter element can flow into the inner bottom of the main filter element through the ventilation pipe and the air blowing cylinder, and then flow out from the natural gas outlet pipe that connects the bottom of the main cylinder body and the inside of the main filter element, realizing the transportation and filtration of natural gas.

[0010] Further, the filter further includes a secondary cylinder body and a secondary filter element. An anti-flushing pipeline is provided between the top end of the secondary cylinder body and the bottom side wall of the main cylinder body. The inner top of the secondary filter element and the inner bottom of the main cylinder body are both connected to the inside of the anti-flushing pipeline. A first valve is installed on the anti-flushing pipeline. The bottom side wall of the secondary cylinder body is connected with an air outlet pipeline. Opening the first valve can enable the solid impurities in the main cylinder body to enter the inside of the secondary filter element along with the air flow through the anti-flushing pipeline, which helps to clean the solid impurities in the main cylinder body, transfer the solid impurities filtered out in the main cylinder body to the secondary filter element. After running continuously for a period of time, close the first valve on the anti-flushing pipeline, and then disassemble the secondary filter element to clean the solid impurities inside it. The main cylinder body and the main filter element can always continuously carry out the transportation and filtration of natural gas. When disassembling and maintaining the secondary filter element, the main cylinder body and the main filter element do not stop the transportation and filtration of natural gas.

[0011] Further, a second valve is installed on the natural gas outlet pipe at the bottom end of the main cylinder body. The outlet end of the second valve is connected to a confluence pipeline, and the outlet pipeline is connected to the confluence pipeline, so that the natural gas filtered by the auxiliary cylinder body and the auxiliary filter element can be confluent and output on the confluence pipeline. A third valve is installed on the outlet pipeline to control the on-off of the outlet pipeline. When the first valve and the third valve are opened and the second valve is closed, the natural gas and the backwashing high-pressure gas entering the main cylinder body can carry the solid impurities in the main cylinder body into the interior of the auxiliary filter element through the backwashing pipeline. The natural gas passes through the auxiliary filter element from the inside to the outside and then flows into the confluence pipeline through the outlet pipeline, while the solid impurities are blocked inside the auxiliary filter element. While cleaning the solid impurities in the main cylinder body, the auxiliary filter element is used for natural gas transmission and distribution filtration without stopping the natural gas transmission and distribution filtration. The reason for closing the second valve to introduce the natural gas in the main cylinder body into the backwashing pipeline is to ensure that a large enough natural gas flow can carry the solid impurities in the main cylinder body into the auxiliary filter element.

[0012] Further, a bypass pipeline is connected to the confluence pipeline. The bypass pipeline is connected to the outer end of the air inlet interface arranged at the top end of the main cylinder body. The high-pressure hose is connected to the inner end of the air inlet interface at the inner top of the main filter element, and can divert the clean natural gas entering the confluence pipeline after filtration to the bypass pipeline and reverse-transport it into the air blowing cylinder as the backwashing high-pressure gas of the main filter element. A booster pump is installed on the bypass pipeline to pressurize the natural gas diverted to the bypass pipeline and then transport it to the air blowing cylinder, so that the pressure of the high-pressure gas blown out of the air blowing holes is greater than the pressure of the natural gas in the annulus between the main filter element and the main cylinder body, ensuring that the high-pressure gas blown out of the air blowing holes on the air blowing cylinder can pass through the side wall of the main filter element from the inside to the outside to backwash the main filter element. A fourth valve is installed on the bypass pipeline between the booster pump and the confluence pipeline. When the main filter element does not need to be backwashed with high-pressure gas, the fourth valve is closed to prevent the natural gas in the confluence pipeline from being diverted to the bypass pipeline.

[0013] The present invention also provides a method for backwashing the filter element without stopping the natural gas transmission and distribution filtration of the filter. The steps for backwashing the main filter element while the filter does not stop the natural gas transmission and distribution filtration are as follows: S1. Continuous natural gas transmission and distribution filtration: The first valve and the third valve are in the closed state, and the second valve is in the open state. The natural gas containing solid impurities enters the interior of the main cylinder body through the natural gas inlet pipe at the top of the main cylinder body. The natural gas passes through the main filter element and enters it, and then is discharged into the confluence pipeline through the natural gas outlet pipe at the bottom end of the main cylinder body. The solid impurities are blocked outside by the main filter element. The solid impurities stay in the annulus between the main cylinder body and the main filter element or adhere to the outer side wall of the main filter element, and the natural gas is sequentially transmitted and filtered. S2. Backwashing of the main filter element: Start the motor. The motor drives the lead screw to reciprocate between forward and reverse rotations. The lead screw drives the air blowing cylinder to reciprocate axially inside the main filter element. At the same time, high-pressure gas is delivered into the air blowing cylinder through the high-pressure hose. The high-pressure gas in the air blowing cylinder blows towards the inner sidewall of the main filter element through a number of air blowing holes. The high-pressure gas passes through the sidewall of the main filter element from the inside to the outside and impacts the solid impurities attached to the outer sidewall of the main filter element, causing the solid impurities to fall off from the outer sidewall of the main filter element, so as to backwash the main filter element. This can prevent solid impurities from attaching to the outer sidewall of the main filter element and causing blockage. Even when solid impurities attach to the outer sidewall of the main filter element and cause a certain section of the main filter element to be blocked, based on the effect of the mobile backwashing inside the main filter element by the backwashing device, when the air blowing cylinder moves to the blocked section, it can backwash the main filter element, causing the solid impurities attached to the outer sidewall of the main filter element to fall off, so as to relieve the blockage of the main filter element and restore the filtering effect of the main filter element. The motor can drive the air blowing cylinder to move axially inside the main filter element. The air blowing cylinder backwashes the main filter element while moving inside the main filter element, can perform mobile backwashing inside the main filter element, and can backwash each section of the main filter element successively, which helps the entire main filter element to restore the filtering effect. While the filter continuously distributes and filters natural gas, the backwashing device can operate independently to backwash the main filter element; S3. Cleaning of solid impurities in the main cylinder body: Open the first valve and the third valve, close the second valve. The natural gas entering the main cylinder body through the natural gas inlet pipe and the backwashing high-pressure gas blown from the inside to the outside of the main filter element carry the solid impurities in the main cylinder body into the inside of the secondary filter element through the backwashing pipeline. The natural gas passes through the secondary filter element from the inside to the outside and then flows into the confluence pipeline through the air outlet pipeline. The solid impurities are blocked inside the secondary filter element, realizing continuous distribution and filtration of natural gas, can transfer the solid impurities filtered out in the main cylinder body to the secondary filter element, and can clean the solid impurities in the main cylinder body; S4. Cleaning of solid impurities in the secondary filter element: Open the second valve, close the first valve and the third valve, and perform continuous distribution and filtration of natural gas as in step S1. The worker opens the secondary cylinder body to disassemble the secondary filter element and clean the solid impurities inside the secondary filter element, while the main cylinder body and the main filter element always keep working continuously without stopping the distribution and filtration of natural gas; Clean or replace the secondary filter element, and install the secondary filter element inside the secondary cylinder body for the next cleaning of the main filter element.

[0014] Further, in the step S2, start the booster pump. The booster pump pressurizes the natural gas diverted from the confluence pipeline to the bypass pipeline and then delivers it into the air blowing cylinder, so that the pressure of the high-pressure gas blown out of the air blowing holes is greater than the pressure of the natural gas in the annulus between the main filter element and the main cylinder body, ensuring that the high-pressure gas blown out of the air blowing holes on the air blowing cylinder can pass through the sidewall of the main filter element from the inside to the outside to backwash the main filter element.

[0015] As can be seen from the above technical solutions, a filter and a method for backwashing the filter element without stopping the distribution and filtration of natural gas provided by the present invention have the beneficial effects that: This filter can perform backwashing of the main filter element under the condition of not stopping the filtration of natural gas transmission and distribution. Natural gas containing solid impurities continuously enters the interior of the main cylinder through the natural gas inlet pipe on the side wall of the main cylinder for filtration. The natural gas can enter the main filter element, while the solid impurities are blocked outside the main filter element, thus remaining in the annulus between the main cylinder and the main filter element or adhering to the outer side wall of the main filter element. The natural gas entering the main filter element can flow out of the main cylinder through the natural gas outlet pipe to achieve the filtration of natural gas transmission and distribution; during the above-mentioned natural gas transmission and distribution filtration process, the backwashing device can operate independently. The high-pressure gas transported to the interior of the blowing cylinder through the high-pressure hose can be blown out from the blowing holes and pass through the side wall of the main filter element from the inside to the outside to blow off the solid impurities adhering to the outer side wall of the main filter element, performing backwashing of the main filter element from the inside to the outside, which can prevent solid impurities from adhering to the outer side wall of the main filter element and causing blockage. Even when solid impurities adhere to the outer side wall of the main filter element and cause a certain section of the main filter element to be blocked, based on the effect of the backwashing device performing mobile backwashing inside the main filter element, when the blowing cylinder moves to the blocked section, it can backwash the main filter element, causing the solid impurities adhering to the outer side wall of the main filter element to fall off, so as to relieve the blockage of the main filter element and restore the filtering effect of the main filter element. The driving mechanism can drive the blowing cylinder to move axially inside the main filter element. The blowing cylinder moves and backwashes the main filter element at the same time inside the main filter element, which can perform mobile backwashing inside the main filter element and can backwash each section of the main filter element successively, helping the entire main filter element to restore the filtering effect; this filter with an independently operable backwashing device can prevent blockage of the main filter element without stopping the filtration of natural gas transmission and distribution, and can quickly restore the filtering effect of the filter element when the main filter element is blocked, without the need to stop the machine and gas supply for maintaining the main filter element. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals.

[0017] Figure 1 It is a schematic cross-sectional structure diagram of Embodiment 1 of the present invention.

[0018] Figure 2 It is Figure 1 a partially enlarged structure diagram at position A in

[0019] Figure 3 It is Figure 1 a partially enlarged structure diagram at position B in

[0020] Figure 4 It is Figure 1 a partially enlarged structure diagram at position C in

[0021] Figure 5 It is a schematic three-dimensional structure diagram of Embodiment 1 of the present invention.

[0022] Figure 6 Explosion structure schematic diagram of Embodiment 1 of the present invention.

[0023] Figure 7 is Figure 6 Partial enlarged structure schematic diagram at position D in

[0024] Figure 8 Cross-sectional structure schematic diagram of Embodiment 2 of the present invention.

[0025] Figure 9 Three-dimensional structure schematic diagram of Embodiment 2 of the present invention.

[0026] Figure 10 Split structure schematic diagram of the secondary filter element in Embodiment 2 of the present invention.

[0027] In the drawings: 1 - main cylinder body, 2 - main filter element, 3 - air blowing cylinder, 4 - high-pressure hose, 5 - driving mechanism, 5.1 - motor, 5.2 - lead screw, 5.3 - guide rod, 6 - filter element positioning ring, 7 - air blowing hole, 8 - annular sealing ring, 9 - ventilation pipe, 10 - internal threaded pipe, 11 - guide pipe, 12 - seal, 13 - X-shaped support plate, 14 - secondary cylinder body, 15 - secondary filter element, 16 - backwashing pipeline, 17 - first valve, 18 - air outlet pipeline, 19 - second valve, 20 - confluence pipeline, 21 - third valve, 22 - bypass pipeline, 23 - air inlet interface, 24 - booster pump, 25 - fourth valve.

[0028] It should be noted here that in the above drawings, each component or part is not necessarily drawn according to the actual proportion. Detailed implementation manners

[0029] The embodiments of the technical solution of the present invention will be described in detail below with reference to the drawings. The following embodiments are only used to illustrate the technical solution of the present invention more clearly, so they are only examples and cannot be used to limit the protection scope of the present invention.

[0030] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "top", "bottom", "inner", "outer", "front", "rear", "left", "right", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention.

[0031] Embodiment 1

[0032] A filter, such as Figure 1As shown, it mainly consists of a main cylinder body 1, a main filter element 2, and an anti-flushing device. The anti-flushing device includes a blowing cylinder 3, a high-pressure hose 4, and a driving mechanism 5.

[0033] As Figure 1 and Figure 5 shown, a natural gas inlet pipe is provided on the top side wall of the main cylinder body 1, and a natural gas outlet pipe is provided at its bottom end; Specifically, as Figures 1 to 6 shown, the main cylinder body 1 is composed of a cylindrical round pipe and circular sealing plates bolted to both ends (the bolts are not shown in the figure). Filter element positioning rings 6 are welded or integrally formed on the inner surfaces of the two circular sealing plates. The main filter element 2 is detachably installed inside the main cylinder body 1 and is coaxial with the main cylinder body 1. An annular space is formed between the inner side wall of the main cylinder body 1 and the outer side wall of the main filter element 2. The two ends of the main filter element 2 are respectively inserted into the filter element positioning rings 6 on the two circular sealing plates. When the main cylinder body 1 is assembled, the main filter element 2 is clamped and fixed inside it; the main cylinder body 1 is made of stainless steel material, and the structural principle of the main filter element 2 is prior art; As Figure 1 , Figure 3 and Figure 4 shown, the natural gas inlet pipe communicates with the top of the annular space inside the main cylinder body 1, and the natural gas outlet pipe is located inside the main filter element 2 and communicates with the inner bottom of the main filter element 2. The natural gas containing solid impurities enters the annular space inside the main cylinder body 1 through the natural gas inlet pipe. The natural gas can pass through the main filter element 2 and enter it, while the solid impurities are blocked outside the main filter element 2 by the main filter element 2. The natural gas inside the main filter element 2 is discharged through the natural gas outlet pipe for natural gas transmission and distribution filtration; the structures of the above-mentioned main cylinder body 1 and main filter element 2 and the natural gas filtration principle are all well-known prior arts and will not be elaborated here.

[0034] As Figure 1 , Figure 2 and Figure 7 shown, the blowing cylinder 3 is a hollow cylindrical structure with both ends closed. It is arranged inside the main filter element 2 and can move axially inside the main filter element 2. A plurality of blowing holes 7 are provided on the side wall of the blowing cylinder 3; As Figure 1 and Figure 6 shown, the high-pressure hose 4 is arranged inside the main filter element 2. Its bottom end is connected to the top end of the blowing cylinder 3 and communicates with the inside of the blowing cylinder 3. Its top end is externally connected to a high-pressure gas supply source. High-pressure gas can be transported into the inside of the blowing cylinder 3 through the high-pressure hose 4. The high-pressure gas inside the blowing cylinder 3 is blown out through the blowing holes 7 to impact the side wall of the main filter element 2. The high-pressure gas can pass through the side wall of the main filter element 2 from the inside to the outside to blow off the solid impurities attached to the outer side wall of the main filter element 2, and perform an inside-to-outside backwash on the main filter element 2; specifically, as Figure 2 , Figure 3 and Figure 7As shown, intake interfaces 23 for connecting high-pressure hoses 4 are respectively provided at the top ends of the main cylinder body 1 and the air blowing cylinder 3. The top end of the high-pressure hose 4 is threadedly connected to the intake interface 23 at the top end of the main cylinder body 1, and the bottom end of the high-pressure hose 4 is threadedly connected to the intake interface 23 on the air blowing cylinder 3. The high-pressure hose 4 is composed of an inner lining layer (synthetic rubber layer), a reinforcing layer (metal braided layer), an outer covering layer (synthetic rubber layer), an additional layer (antistatic layer), etc., and has high pressure resistance, corrosion resistance, and good flexibility; As Figure 2 and Figure 7 shown, annular sealing rings 8 for forming a seal with the inner side wall of the main filter element 2 are fixed on both the top side wall and the bottom side wall of the air blowing cylinder 3. The annular sealing ring 8 can move inside the main filter element 2 along with the air blowing cylinder 3, and the annular sealing ring 8 forms a sliding sealing structure on the inner side wall of the main filter element 2; As Figure 2 and Figure 7 shown, an air vent pipe 9 is fixed on the air blowing cylinder 3. Both ends of the air vent pipe 9 penetrate through the top end and the bottom end of the air blowing cylinder 3 respectively. The air vent pipe 9 is used to connect the inside of the main filter element 2 at the upper and lower ends of the air blowing cylinder 3, so that the natural gas that enters the inside of the main filter element 2 through the top side wall of the main filter element 2 can flow into the inner bottom of the main filter element 2 through the air vent pipe 9 and through the air blowing cylinder 3, and then flow out from the natural gas outlet pipe that connects the bottom of the main cylinder body 1 and the inside of the main filter element 2, realizing the transportation and filtration of natural gas and avoiding the air blowing cylinder 3 from blocking the natural gas transportation inside the main filter element 2.

[0035] As Figure 1 、 Figure 2 and Figure 6As shown, the driving mechanism 5 is used to drive the blowing cylinder 3 to move axially back and forth inside the main filter element 2, and includes a motor 5.1, a screw 5.2 and a guide rod 5.3; the motor 5.1 is installed on the outer top of the main cylinder body 1, and an internal threaded tube 10 coaxial with the blowing cylinder 3 is fixed at the center, the screw 5.2 penetrates the internal threaded tube 10 and is threadedly connected to the internal threaded tube 10, a guide tube 11 is fixed on the blowing cylinder 3, and the central axis of the guide tube 11 is parallel to the central axis of the blowing cylinder 3, the guide rod 5.3 penetrates the guide tube 11, and the two ends of the guide rod 5.3 are respectively connected to the top and bottom ends of the main cylinder body 1, and the bottom end of the screw 5.2 is rotatably connected to the inner bottom of the main cylinder body 1. The bottom end of the lead screw 5.2 is rotatably connected to the inner bottom of the main cylinder body 1 through a rotating bearing, the top end of the lead screw 5.2 penetrates the top end of the main cylinder body 1 and is rotatably sealed with the top end of the main cylinder body 1 through a seal 12, the top end of the lead screw 5.2 is transmission-connected to the power output end of the motor 5.1, and the motor 5.1 is used to drive the lead screw 5.2 to rotate so as to drive the air cylinder 3 to move axially inside the main filter element 2; the motor 5.1 can drive the lead screw 5.2 to rotate, and the guide rod 5.3 can limit the rotation of the air cylinder 3. The motor 5.1 is a forward and reverse motor 5.1, and the motor 5.1 can drive the lead screw 5.2 to rotate forward and reverse, and the lead screw 5.2 can drive the air cylinder 3 to reciprocate along its axial direction; Specifically, Figure 4 As shown, an air outlet is opened in the center of the circular sealing plate at the bottom of the main cylinder body 1. To ensure that the lead screw 5.2 is coaxial with the main cylinder body 1 and the bottom end of the lead screw 5.2 is rotatably connected to the inner bottom of the main cylinder body 1, an X-shaped support plate 13 is welded on the top surface of the circular sealing plate, and a rotating bearing is installed on the top surface of the X-shaped support plate 13 to be rotatably connected to the bottom end of the lead screw 5.2. The X-shaped support plate 13 will not completely block the air outlet, so that the filtered natural gas can be discharged through the air outlet; Figure 3 As shown, the seal 12 between the top of the screw 5.2 and the top of the main cylinder 1 is a rotating shaft seal 12, which is an existing product, and is composed of a dynamic ring (rotating with the screw 5.2), a static ring (fixed at the top of the main cylinder 1), a spring, and an auxiliary sealing ring (O-ring, bellows, etc.). It is a conventional mechanical seal, a sealing device used to prevent fluid (liquid or gas) leakage between a rotating shaft and a stationary part, and is widely used in rotating equipment such as pumps, compressors, turbines, and motors 5.1, such as Bal Seal® spring energy storage rotating seal 12; the screw 5.2 and the internal threaded tube 10 use a screw 5.2 nut, which has the characteristics of high precision, high efficiency and high responsiveness.

[0036] As a preferred embodiment, in this embodiment, the annular sealing ring 8 is made of rubber material, which can be made into two structures as shown in the figure; Figure 2 and Figure 7As shown, one of the structures is a ring-shaped cap, which is sleeved on the end of the air blowing cylinder 3. Both ends of the air blowing cylinder 3 have annular protrusions. The annular sealing ring 8 is sleeved on the annular protrusions and covers the end face of the air blowing cylinder 3. This is also the structure of the annular sealing ring 8 adopted in this embodiment; another structure is a circular ring sleeved on the end of the air blowing cylinder 3 (not shown in the figure). To improve stability, an annular clamping groove for the annular sealing ring 8 to be inserted into is provided at the end of the air blowing cylinder 3. The inner side wall of the air blowing cylinder 3 is adhesively fixed in the annular clamping groove of the air blowing cylinder 3; for the annular sealing rings 8 of the above two structures, the outer side wall of each is in interference fit with the inner side wall of the main filter element 2. When the air blowing cylinder 3 moves axially in the main filter element 2, the rubber sealing ring is always in interference fit with the inner side wall of the main filter element 2, and the rubber sealing ring can move along with the air blowing cylinder 3. This sealing structure is similar to the sliding sealing structure between the piston and the cylinder body inside a syringe; Under the sliding sealing action of the two annular sealing rings 8, the high-pressure gas blown out from the air holes 7 on the side wall of the air blowing cylinder 3 impacts the side wall of the main filter element 2 between the two annular sealing rings 8, and performs backwashing on the main filter element 2 from the inside to the outside, reducing the leakage of the high-pressure gas blown out from the air holes 7 through the gaps between the top of the air blowing cylinder 3 and the inner side wall of the main filter element 2 or between the bottom of the air blowing cylinder 3 and the inner side wall of the main filter element 2 to the main filter element 2 on the upper and lower sides of the air blowing cylinder 3, so that more high-pressure gas can pass through the side wall of the main filter element 2 from the inside to the outside to blow off the solid impurities attached to the outer side wall of the main filter element 2, and promoting the restoration of the filtering effect of the part of the side wall of the main filter element 2 that coincides with the air blowing cylinder 3.

[0037] As a preferred embodiment, in this embodiment, as Figure 1 and Figure 6 shown, the high-pressure hose 4 is spiral. When the air blowing cylinder 3 reciprocates axially along the main filter element 2, the spiral high-pressure hose 4 can stretch and contract accordingly, which can ensure the supply of the backwashing high-pressure gas in the air blowing cylinder 3; specifically, the spiral high-pressure hose 4 is similar to a spring structure. The lead screw 5.2 is located inside the spiral high-pressure hose 4, and the lead screw 5.2 has a guiding effect on the stretching and contraction of the spiral high-pressure hose 4.

[0038] Embodiment 2

[0039] A filter, which is different from that in Embodiment 1 in that: as Figure 8 shown, in addition to including the main cylinder body 1, the main filter element 2 and the backwashing device in Embodiment 1, this filter further includes a secondary cylinder body 14 and a secondary filter element 15.

[0040] As Figures 8 to 10As shown, the secondary cylinder body 14, the secondary filter element 15 and their installation structure are similar to those of the main cylinder body 1 and the main filter element 2 in the above-mentioned Embodiment 1. The secondary cylinder body 14 is also composed of a cylindrical round pipe and circular sealing plates bolted at both ends (the bolts are not shown in the figure). The secondary filter element 15 is detachably installed inside the main cylinder body 1 to facilitate disassembly and assembly. The difference is that the natural gas inlet pipe on the secondary cylinder body 14 is arranged at the top of the secondary cylinder body 14 and is internally connected to the inside of the secondary filter element 15. The natural gas outlet pipe on the secondary cylinder body 14 is arranged on the bottom side wall of the secondary cylinder body 14. Inside the secondary filter element 15, the natural gas is filtered from the inside outwards.

[0041] As Figure 8 and Figure 9 As shown, a backwash pipeline 16 is arranged between the top of the secondary cylinder body 14 and the bottom side wall of the main cylinder body 1. The bottom side wall of the main cylinder body 1 is provided with a backwash outlet pipe, and the backwash outlet pipe communicates with the bottom of the inner annulus of the main cylinder body 1. The two ends of the backwash pipeline 16 are respectively connected to the backwash outlet pipe at the bottom of the main cylinder body 1 and the natural gas inlet pipe at the top of the secondary filter element 15. A first valve 17 is installed on the backwash pipeline 16. The bottom side wall of the secondary cylinder body 14 is connected with an outlet pipeline 18. Opening the first valve 17 can enable the solid impurities in the main cylinder body 1 to enter the inside of the secondary filter element 15 along with the airflow through the backwash pipeline 16, which helps to clean the solid impurities in the main cylinder body 1 and transfer the solid impurities filtered out in the main cylinder body 1 to the secondary filter element 15. After continuous operation for a period of time, the first valve 17 on the backwash pipeline is closed, and then the secondary filter element 15 is disassembled to clean the solid impurities inside it (as Figure 10 shown), while the main cylinder body 1 and the main filter element 2 can always continuously carry out natural gas transportation and filtration. When the secondary filter element 15 is disassembled and maintained, the main cylinder body 1 and the main filter element 2 do not stop natural gas transportation and filtration.

[0042] As Figure 8 and Figure 9As shown, a second valve 19 is installed on the natural gas outlet pipe at the bottom of the main cylinder body 1. The outlet end of the second valve 19 is connected to a confluence pipeline 20. The gas outlet pipe 18 is connected to the confluence pipeline 20, so that the natural gas filtered by the auxiliary cylinder body 14 and the auxiliary filter element 15 can converge to the confluence pipeline 20 for output. A third valve 21 is installed on the gas outlet pipe 18 to control the on-off of the gas outlet pipe 18. When the first valve 17 and the third valve 21 are opened and the second valve 19 is closed, the natural gas and the backwashing high-pressure gas entering the main cylinder body 1 can carry the solid impurities in the main cylinder body 1 through the backwashing pipeline 16 into the interior of the auxiliary filter element 15. The natural gas passes through the auxiliary filter element 15 from the inside to the outside and then flows into the confluence pipeline 20 through the gas outlet pipe 18, while the solid impurities are blocked inside the auxiliary filter element 15. While cleaning the solid impurities in the main cylinder body 1, the auxiliary filter element 15 is used for natural gas transmission and distribution filtration without stopping the natural gas transmission and distribution filtration. The reason for closing the second valve 19 to introduce the natural gas in the main cylinder body 1 into the backwashing pipeline 16 is to ensure that a large enough natural gas flow can carry the solid impurities in the main cylinder body 1 into the auxiliary filter element 15.

[0043] As Figure 8 and Figure 9 shown, a bypass pipeline 22 is connected to the confluence pipeline 20. The bypass pipeline 22 is connected to the outer end of the air inlet interface 23 provided at the top of the main cylinder body 1. The high-pressure hose 4 is connected to the inner end of the air inlet interface 23 at the inner top of the main filter element 2, which can divert the clean natural gas entering the confluence pipeline 20 after filtration to the bypass pipeline 22 and reverse-transport it into the air blowing cylinder 3 as the backwashing high-pressure gas for the main filter element 2. A booster pump 24 is installed on the bypass pipeline 22, which can pressurize the natural gas diverted to the bypass pipeline 22 and then transport it to the air blowing cylinder 3, so that the pressure of the high-pressure gas blown out of the air blowing holes 7 is greater than the pressure of the natural gas in the annulus between the main filter element 2 and the main cylinder body 1, ensuring that the high-pressure gas blown out of the air blowing holes 7 on the air blowing cylinder 3 can pass through the side wall of the main filter element 2 from the inside to the outside to backwash the main filter element 2. A fourth valve 25 is installed on the bypass pipeline 22 between the booster pump 24 and the confluence pipeline 20. When the main filter element 2 does not need to be backwashed with high-pressure gas, the fourth valve 25 is closed to prevent the natural gas in the confluence pipeline 20 from being diverted to the bypass pipeline 22. Each of the above valves is an existing product and can be a ball valve, a gate valve, or a butterfly valve.

[0044] As a preferred embodiment, in this embodiment, the bottom of the auxiliary filter element 15 is a closed structure (not shown in the figure). After removing the circular sealing plate at the bottom of the auxiliary cylinder body 14, the auxiliary filter element 15 is taken out from the bottom of the auxiliary cylinder body 14. Based on the closed structure at the bottom of the auxiliary filter element 15, the solid impurities filtered inside it will not fall out of the auxiliary filter element 15 when the circular sealing plate is removed.

[0045] Embodiment 3

[0046] A method for backwashing the filter element of a filter without stopping natural gas transmission and distribution filtration, asFigure 8 and Figure 9 As shown in Figure 9 , the steps for the filter described in Embodiment 2 above to continuously filter natural gas during transportation and simultaneously backwash the main filter element 2 are as follows: S1. Continuous transportation and filtration of natural gas: The first valve 17 and the third valve 21 are in the closed state, and the second valve 19 is in the open state. Natural gas containing solid impurities enters the interior of the main cylinder 1 through the natural gas inlet pipe at the top of the main cylinder 1. The natural gas passes through the main filter element 2 and enters it, and then is discharged into the confluence pipeline 20 through the natural gas outlet pipe at the bottom end of the main cylinder 1. The solid impurities are blocked outside by the main filter element 2 and remain in the annulus between the main cylinder 1 and the main filter element 2 or adhere to the outer sidewall of the main filter element 2; S2. Backwashing of the main filter element 2: Start the motor 5.1. The motor 5.1 drives the lead screw 5.2 to reciprocate between forward and reverse rotations. The lead screw 5.2 drives the air blowing cylinder 3 to reciprocate axially inside the main filter element 2. At the same time, start the booster pump 24. The booster pump 24 pressurizes the natural gas diverted from the confluence pipeline 20 to the bypass pipeline 22 and then transports it into the air blowing cylinder 3. The high-pressure gas in the air blowing cylinder 3 blows towards the inner sidewall of the main filter element 2 through a number of air blowing holes 7. The high-pressure gas passes through the sidewall of the main filter element 2 from the inside to the outside and impacts the solid impurities adhering to the outer sidewall of the main filter element 2, causing the solid impurities to fall off from the outer sidewall of the main filter element 2 to backwash the main filter element 2, which can prevent solid impurities from adhering to the outer sidewall of the main filter element 2 and causing blockage. Even when solid impurities adhere to the outer sidewall of the main filter element 2 and cause blockage in a certain section of the main filter element 2, based on the effect of the mobile backwashing inside the main filter element 2 by the backwashing device, when the air blowing cylinder 3 moves to the blocked section, it can backwash the main filter element 2, causing the solid impurities adhering to the outer sidewall of the main filter element 2 to fall off, so as to relieve the blockage of the main filter element 2 and restore the filtering effect of the main filter element 2. The motor 5.1 can drive the air blowing cylinder 3 to move axially inside the main filter element 2. The air blowing cylinder 3 backwashes the main filter element 2 while moving inside the main filter element 2, which can perform mobile backwashing inside the main filter element 2 and can backwash each section of the main filter element 2 successively, helping the entire main filter element 2 to restore the filtering effect. While the filter continuously transports and filters natural gas, the backwashing device can operate independently to backwash the main filter element 2; After being pressurized by the booster pump 24, the pressure of the high-pressure gas blown out by the air blowing holes 7 is greater than the pressure of the natural gas in the annulus between the main filter element 2 and the main cylinder 1, ensuring that the high-pressure gas blown out by the air blowing holes 7 on the air blowing cylinder 3 can pass through the sidewall of the main filter element 2 from the inside to the outside to backwash the main filter element 2; S3. Cleaning of solid impurities in the main cylinder body 1: Open the first valve 17 and the third valve 21, close the second valve 19. The natural gas entering the main cylinder body 1 through the natural gas inlet pipe and the backwashing high-pressure gas blown from the inside to the outside of the main filter element 2 carry the solid impurities in the main cylinder body 1 into the inside of the secondary filter element 15 through the backwashing pipeline 16. The natural gas passes through the secondary filter element 15 from the inside to the outside and then flows into the confluence pipeline 20 through the air outlet pipeline 18. The solid impurities are blocked inside the secondary filter element 15, realizing continuous gas transmission and filtration of natural gas. The solid impurities filtered out in the main cylinder body 1 can be transferred to the secondary filter element 15, and the solid impurities in the main cylinder body 1 can be cleaned up. S4. Cleaning of solid impurities in the secondary filter element 15: Open the second valve 19, close the first valve 17 and the third valve 21. Conduct continuous gas transmission and filtration of natural gas as in step S1. The worker opens the secondary cylinder body 14 to disassemble the secondary filter element 15 and clean the solid impurities inside the secondary filter element 15, while the main cylinder body 1 and the main filter element 2 always keep working without stopping the gas transmission and filtration of natural gas. Clean or replace the secondary filter element 15, and install the secondary filter element 15 in the secondary cylinder body 14 for the next use.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered by the scope of the claims and the description of the present invention.

Claims

1. A filter, comprising a main cylinder, a main filter element and a backwashing device, wherein the main filter element is arranged inside the main cylinder, characterized in that: The backwashing device comprises: The air blowing cylinder is arranged inside the main filter element, and the air blowing cylinder is a cylindrical structure with closed ends, and a plurality of air blowing holes are opened on its side wall; A high-pressure hose for conveying high-pressure gas to the inside of the blow cylinder. The high-pressure hose is located inside the main filter element. Its bottom end is connected to the top of the blow cylinder and communicates with the inside of the blow cylinder. Its top end is externally connected to a high-pressure gas supply source. The high-pressure gas entering the blow cylinder is blown out through a number of blowing holes to backwash the main filter element from the inside to the outside; A driving mechanism for driving the air cylinder to reciprocate axially inside the main filter element.

2. The filter according to claim 1, characterized in that: The top side wall and the bottom side wall of the blowing cylinder are both fixed with an annular sealing ring for forming a seal with the inner side wall of the main filter element.

3. The filter according to claim 1, characterized in that: The high-pressure hose is in a spiral shape.

4. The filter according to any one of claims 1 to 3, characterized in that: The driving mechanism includes a motor, a lead screw and a guide rod; the motor is installed on the outer top of the main cylinder, and an internal threaded tube coaxial with the main cylinder is fixed at the center of the air blowing cylinder, and the lead screw passes through the internal threaded tube and is threadedly connected to the main cylinder; a guide tube is fixed on the air blowing cylinder, and the guide rod passes through the guide tube and slides with the guide tube, and the two ends of the guide rod are respectively connected to the top and bottom ends of the main cylinder; the bottom end of the lead screw is rotatably connected to the inner bottom of the main cylinder, and its top end passes through the top of the main cylinder and is rotatably sealed with the top of the main cylinder through a seal, and the top end of the lead screw is transmission-connected to the power output end of the motor, and the motor is used to drive the lead screw to rotate to drive the air blowing cylinder to move axially inside the main filter element.

5. The filter according to claim 4, characterized in that: A ventilation pipe is fixed on the air cylinder, and two ends of the ventilation pipe respectively penetrate the top end and the bottom end of the air cylinder. The ventilation pipe is used to connect the interior of the main filter element at the upper and lower ends of the air cylinder.

6. The filter according to claim 5, characterized in that: The filter also includes a secondary cylinder and a secondary filter element. A recoil pipe is arranged between the top of the secondary cylinder and the bottom side wall of the main cylinder. The inner top of the secondary filter element and the inner bottom of the main cylinder are both connected to the inside of the recoil pipe. A first valve is installed on the recoil pipe. The bottom side wall of the secondary cylinder is connected to an air outlet pipe.

7. The filter according to claim 6, wherein the top side wall of the main cylinder is provided with a natural gas inlet pipe, and the bottom end thereof is provided with a natural gas outlet pipe connected to the bottom of the main filter element, characterized in that: A second valve is installed on the natural gas outlet pipe, an outlet end of the second valve is connected to a converging pipe, the outlet pipe is connected to the converging pipe, and a third valve is installed on the outlet pipe.

8. The filter according to claim 7, characterized in that: The confluence pipe is connected to a bypass pipe, which is connected to the outer end of the air inlet interface arranged at the top of the main cylinder body, and the high-pressure hose is connected to the inner end of the air inlet interface at the inner top of the main filter element, and a booster pump is installed on the bypass pipe.

9. A method for backwashing a filter element of a filter without stopping natural gas transmission and distribution filtration as claimed in claim 8, characterized in that: The steps of backwashing the main filter element without stopping the natural gas transmission and distribution filtration are as follows: S1. Continuous transmission and filtration of natural gas: The first valve and the third valve are in the closed state, and the second valve is in the open state. Natural gas containing solid impurities enters the main cylinder through the natural gas inlet pipe at the top of the main cylinder, passes through the main filter element and enters it, and then is discharged into the confluence pipeline through the natural gas outlet pipe at the bottom of the main cylinder. The solid impurities are blocked outside by the main filter element, and the solid impurities are retained in the annulus between the main cylinder and the main filter element or attached to the outer wall of the main filter element; S2. Backwashing of the main filter element: Start the motor, and the motor drives the lead screw to switch back and forth between forward and reverse rotation. The lead screw drives the air cylinder to move back and forth along the axial direction inside the main filter element. At the same time, the high-pressure gas is transported to the air cylinder through the high-pressure hose. The high-pressure gas in the air cylinder is blown toward the inner wall of the main filter element through a number of blowing holes. The high-pressure gas passes through the side wall of the main filter element from the inside to the outside and impacts the solid impurities attached to the outer wall of the main filter element to backwash the main filter element. S3, cleaning of solid impurities in the main cylinder: open the first valve and the third valve, close the second valve, the natural gas entering the main cylinder through the natural gas inlet pipe and the backwashing high-pressure gas blown from the inside to the outside of the main filter carry the solid impurities in the main cylinder into the auxiliary filter through the backwash pipe, the natural gas passes through the auxiliary filter from the inside to the outside and then flows into the converging pipe through the gas outlet pipe, the solid impurities are blocked inside the auxiliary filter, and the natural gas is continuously transmitted and filtered; S4, cleaning solid impurities in the auxiliary filter element: open the second valve, close the first valve and the third valve, and continue to transmit and filter natural gas as in step S1, open the auxiliary cylinder to disassemble the auxiliary filter element, and clean the solid impurities in the auxiliary filter element, while the main cylinder and the main filter element continue to work, and the transmission and filtering of natural gas is not stopped.

10. The filter element backwashing method for the filter without stopping the natural gas transmission and distribution filtration according to claim 9 is characterized in that: In step S2, the booster pump is started to pressurize the natural gas diverted from the converging pipe to the bypass pipe and then transport it to the blow cylinder.

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