JP2012157799A - Backwashing strainer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a backwashing strainer by which the backwashing of a filter element can be performed from an upstream side of a raw fluid flow at the time of filtration and the backwashing of the filter element can be performed without contamination of a washing fluid in the filtered raw fluid.SOLUTION: The filter element 3 is incorporated inside a strainer body 2 so that the fluid flow passing the filter element 3 can be moved up and down between a fluid filtering position and a washing position where the fluid passing the filter element 3 flows reverse to that of the time in filtration. The filter element 3 is connected with a driving device 4 via a drive shaft 13 and when a filtration function of the filter element 3 falls, the filter element 3 is moved to the washing position by the driving device 4 and foreign matter stuck to an inner surface of the filter element 3 is washed and removed by backwashing of the fluid.

Description

  This invention is attached to a pipe through which a fluid flows, and a backwashing strainer that cleans the fluid by removing foreign substances contained in the fluid with a filter element, more specifically, when the filtration function is reduced due to clogging of the filter element, The present invention relates to a back-flow cleaning strainer that uses a fluid pressure to clean and remove adhering foreign matter so that the filtration function can be restored.

  Conventionally, the basic structure of a strainer that is attached to a pipe through which a fluid such as water used in factories or plants flows and that removes foreign substances contained in the fluid is a strainer through which the fluid flows. A filter element is incorporated inside the main body, and a fluid flows through the filter element from upstream to downstream to capture foreign matter.

  In the strainer as described above, the filter element is clogged with the passage of filtration time and the filtration function is lowered. Therefore, it is necessary to periodically restore the filtration function. The method of taking out the element, cleaning the filter element manually, and then reassembling has the problem that it takes time and effort to clean and disassemble.

  For this reason, the flow of the fluid to the filter element is switched, the foreign matter adhering to the filter element is peeled off by the pressure of the cleaning fluid that flows in the opposite direction to that during filtration, and the cleaning fluid mixed with foreign matter is separated from the fluid path. A backwashing strainer has been proposed which can be taken out of the part and restored the filtering function of the filter element without disassembling the strainer.

  The conventional backwashing strainer described above incorporates a filter element inside the strainer main body, divides the inside of the strainer main body into a primary side and a secondary side, and supplies the raw fluid supply section that is electrically connected to the primary side to the strainer body. It is connected to the secondary side, provided with a cleaning fluid supply unit for taking out the filtered fluid and switching and supplying the cleaning fluid to the secondary side, and further has a structure in which a cleaning fluid discharge unit is connected to the primary side ( For example, see Patent Document 1).

  During normal filtration, the fluid that has flowed into the primary side from the raw fluid supply unit flows through the filter element to the secondary side, and the filtered fluid from which foreign matter has been removed flows out to the cleaning fluid supply unit.

  To backwash the filter element, close the raw fluid supply part, open the discharge part, supply cleaning fluid from the cleaning fluid supply part to the secondary side, and the cleaning fluid passes through the filter element in the reverse direction of filtration. By doing so, the foreign matter adhering to the filter element is peeled and removed, and the dirty cleaning fluid is taken out together with the foreign matter to the discharge portion, thereby restoring the filter function of the filter element.

Japanese Patent No. 4376068

  By the way, the above-described conventional backwashing strainer performs backwashing while the filter element is fixedly arranged at a fixed position, so that the cleaning fluid is supplied to the filter element from the downstream side of the flow of the raw fluid during filtration. There is an inconvenience that the flow of the raw fluid itself cannot be used for backwashing.

  Further, in the structure in which the cleaning fluid is supplied from the downstream side, the cleaning fluid remains in the downstream pipe line after backwashing, and when the filtration is restarted, the cleaning fluid is mixed into the filtered raw fluid. For this reason, there is an inconvenience that the cleaning fluid flows into the portion where the filtered raw fluid is used.

  Therefore, an object of the present invention is to allow the back washing of the filter element from the upstream side of the flow of the raw fluid at the time of filtration, so that the flow of the raw fluid itself can be used for back washing, and the washing fluid can be used. Even when used, it is an object of the present invention to provide a backwashing strainer capable of backwashing the filter element without mixing a washing fluid into the filtered raw fluid.

  In order to solve the above-described problems, the present invention provides a filter element inside a strainer main body through which a fluid flows, and a cleaning position in which the fluid is filtered and the flow of the fluid passing through the filter element flows in the opposite direction to that during filtration. Installed so that it can move between positions, connect a drive shaft to the filter element, move the filter element to the cleaning position with this drive shaft, and clean and remove foreign matter adhering to the surface of the filter element due to the backflow of fluid It is what you do.

  A foreign matter discharge port may be provided at the bottom of the filter element so that the foreign matter discharge port is closed when the filter element is at the filtering position, and the foreign matter discharge port is opened when the filter element is at the cleaning position.

  Further, a differential pressure switch is connected to the fluid inlet and the fluid outlet of the strainer body, and a fluid introduction path and a washing water introduction path are switchably connected to the fluid inlet of the strainer body so that foreign matter adheres to the surface of the filter element. When the pressure difference more than the set value occurs, the differential pressure switch switches the continuity of the fluid inlet of the strainer body from the fluid introduction path to the washing water introduction path, and at the same time, a drive device linked with the drive shaft It can be activated to move the filter element from the filtration position to the washing position.

  The screen as the surface path material of the filter element can be made of a metal material, a synthetic resin material, or a cloth material.

  Furthermore, a plurality of backwashing strainers can be installed in parallel with the fluid introduction path by using the backwashing strainer, and the backwashing of the filter elements can be performed alternately during the filtration operation.

  Here, the strainer body is formed in a cylindrical shape with a bottom, and the inside thereof is divided into an upper inflow chamber and a lower outflow chamber with a circular bowl-shaped support wall provided in the inner periphery of the intermediate portion as a boundary, and fluid is transferred to the upper inflow chamber. The inlet is provided in communication, and the fluid outlet is provided in communication in the lower outflow chamber.

  The filter element housed in the strainer body is formed in a cylindrical shape having an outer diameter that fits within the inner diameter of the support wall and an upper end that is open, and a flange provided on the outer periphery of the upper end fits in the lower outflow chamber in a state of overlapping the support wall. In this state, it is possible to move upward, and the opening at the upper end communicates with the upper inflow chamber.

  The drive device provided on the upper part of the strainer body uses a cylinder, connects a drive shaft attached to the upper end of the filter element and a piston rod of the cylinder, and a filtration position where the filter element is accommodated in the lower outflow chamber by the cylinder, It can be moved up and down between the backwash position pulled up to the upper inflow chamber.

  The raw fluid that has entered the upper inflow chamber from the fluid inlet of the strainer body flows into the filter element, passes through the screen formed on the peripheral wall of the filter element from the inside to the outside, and is filtered in the lower part. Outflow from the outflow chamber to the fluid outlet.

  A cylindrical foreign matter discharge port is provided in communication with the lower portion of the filter element, and the foreign matter discharge port is movably accommodated in a foreign matter discharge pipe provided at the bottom of the strainer body so that the filter element is placed in the lower outflow chamber. When in the lowered position, the lower end of the foreign matter discharge port is closed, so that the raw fluid does not flow out of the foreign matter discharge port during filtration.

  Also, when the filter element is pulled up to the upper inflow chamber during backwashing, the fluid that has entered the upper inflow chamber from the fluid inlet passes through the screen formed on the peripheral wall of the filter element from the outside to the inside, The foreign matter adhering to the surface of the filter element is washed away by the reverse flow, and the dirty fluid in the filter element is discharged from the opened foreign matter discharge port through the foreign matter discharge pipe.

  According to the present invention, the filter element is incorporated in the strainer body so as to be movable, the filter element is moved to the cleaning position by the drive shaft, and the foreign matter adhering to the surface of the filter element by the back flow of the fluid is cleaned and removed. Therefore, the filter element can be backwashed from the upstream side of the flow of the raw fluid during filtration, and the flow of the raw fluid itself can be used for backwashing.

  In addition, backwashing can be performed from the upstream side of the flow of the original fluid during filtration, and even if a cleaning fluid is used for backwashing, the fluid containing foreign matter is discharged to the outside through the foreign matter discharge port. The filter element can be backwashed without mixing the cleaning fluid with the raw fluid.

  Further, a differential pressure switch is connected to the fluid inlet and the fluid outlet of the strainer body, and when a pressure difference greater than a set value is generated between the fluid inlet and the fluid outlet, the drive device linked with the drive shaft is activated, and the filter element When the filter is moved from the filtration position to the washing position, the function can be automatically restored by backwashing the filter element.

The longitudinal cross-sectional view which shows the normal filtration state which the filter element of the backwashing strainer which concerns on this invention has a filtration position The longitudinal cross-sectional view which shows the state at the time of the backwashing which the filter element of the backwashing strainer concerning this invention exists in a washing | cleaning position The opening and closing operation of the foreign matter discharge port provided continuously with the filter element is shown, (a) is an enlarged vertical sectional view showing the closed state when the filter element is in the filtration position, and (b) is the filter element in the cleaning position. Enlarged longitudinal sectional view showing the state of opening

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  As shown in FIGS. 1 and 2, the backwashing strainer 1 of the present invention incorporates a filter element 3 in the strainer body 2 so as to be movable up and down, and drives the filter element 3 up and down on the strainer body 2. 4 is attached, and a fluid inlet 5 of a raw fluid (liquid) as a filter thread is provided on one side of the vertical axis line outside the strainer body 2 and a fluid outlet 6 is provided on the other side.

  The strainer body 2 is formed in a bottomed circular cylindrical shape, and the inside thereof is divided into an upper inflow chamber 8 and a lower outflow chamber 9 with a circular bowl-shaped support wall 7 provided in the inner periphery of the upper and lower intermediate portions as a boundary, The upper end of the upper inflow chamber 8 is watertightly closed by a lid member 10 coupled to the strainer body 2 using bolts and nuts, and a fluid inlet 5 projecting outward on the side surface of the strainer body 2 is connected to the upper inflow chamber 8. The fluid outlet 6 communicated at the lower side of the side surface, and communicated with the side surface of the lower outflow chamber 9 in the same manner.

  The filter element 3 has a cylindrical shape with an outer diameter that fits and fits inside the inner diameter of the support wall 7. The upper end of the filter element 3 is open and the bottom is narrowed. The outer diameter of the flange 11 is set so as to fit with a slight gap with respect to the inner diameter of the upper inflow chamber 8.

  With the flange 11 overlapping the support wall 7, the entire filter element 3 is accommodated in the lower outflow chamber 9 and can move upward from this state, and the upper end opening is at the upper inflow chamber 8. And the inside communicates with the upper inflow chamber 8.

  The cylindrical peripheral wall of the filter element 3 becomes a screen 12 for filtering the fluid passing in and out, and the surface path material of the screen 12 is formed of any of a metal material, a synthetic resin material, or a cloth material. Has been.

  The lower end of the drive shaft 13 is connected to the upper end portion of the filter element 3 in a coaxial arrangement in a state where the inflow of fluid from the upper end opening is secured, and the drive shaft 13 moves the lid member 10 up and down. The filter element 3 can be moved up and down by the drive shaft 13 from the outside of the strainer body 2 so that the penetrating portion can be passed through, and the penetrating portion can be held in a watertight state by packing, a packing presser, and a ground bolt. ing.

  A driving device 4 is mounted on a lid member 10 fixed to the upper portion of the strainer body 2 via a support column 14. This driving device 4 uses a cylinder in the case of illustration, and the piston rod 4 a is connected to the driving shaft 13 and the shaft. A coupling 15 is used to connect the filter element 3 by the cylinder between a filtration position where the filter element 3 is accommodated in the lower outflow chamber 9 shown in FIG. 1 and a cleaning position where the filter element 3 is pulled up into the upper inflow chamber 8 shown in FIG. It is designed to move up and down.

  A cylindrical foreign matter discharge port 16 is provided coaxially at the bottom of the filter element 3 which is narrowed to a small diameter so that the foreign matter discharge port 16 is connected to the bottom of the strainer body 2. The lower part of the foreign substance discharge pipe 17 is bent at a right angle, and a valve seat 18 for closing the lower end of the foreign substance discharge port 16 is provided at the lower end of the vertical part.

  As shown in FIG. 1, when the filter element 3 is in a filtration position that fits in the lower outflow chamber 9, the lower end opening of the foreign matter discharge port 16 comes into contact with the valve seat 18 and is closed as shown in FIG. The fluid in the filter element 3 is prevented from flowing out into the foreign matter discharge pipe 17.

  2, when the filter element 3 is brought into the cleaning position where the filter element 3 is pulled up to the upper inflow chamber 8, the foreign matter discharge port 16 is also raised integrally as shown in FIG. 3B, and the lower end is separated from the valve seat 18. The lower end opening of the foreign matter discharge port 16 is opened, and the fluid in the filter element 3 flows out from the lower end opening of the foreign matter discharge port 16 to the foreign matter discharge pipe 17.

  A differential pressure switch 19 is connected to the fluid inlet 5 and the fluid outlet 6 of the strainer body 2, and the fluid introduction path 20 and the washing water introduction path 21 are switched to the fluid inlet 5 of the strainer body 2 by operating valves 22 and 23, respectively. When the pressure difference between the fluid inlet 5 and the fluid outlet 6 is detected by the differential pressure switch 19, the drive device 4 and the valves 22 and 23 are operated, and the filter element 3 is switched between filtration and backwashing. Is done automatically.

  The strainer 1 of the present invention is configured as described above, and is connected to the fluid inlet path 20 and the fluid outlet 6 of the fluid inlet 5 in the strainer body 2 in the middle of the pipe through which the raw fluid flows, and is contained in the raw fluid. Foreign matter is filtered by the filter element 3 and trapped. During normal filtration, the filter element 3 is in the filtration position lowered into the lower outflow chamber 9 and supported by the flange 11 as shown in FIG. The upper end opening communicates with the bottom of the upper inflow chamber 8 in a state of overlapping the wall 7, and the lower end opening of the lowered foreign matter discharge port 16 is in contact with the valve seat 18 and closed.

  When the valve 22 of the fluid introduction path 20 is opened, the raw fluid to be filtered flows from the fluid introduction path 20 through the fluid inlet 5 and the upper inflow chamber 8 to the inside of the filter element 3. The foreign material contained in the raw fluid is captured by the screen 12 through the inside 12 from the inside to the outside, and the cleaned fluid flows out from the lower outflow chamber 9 to the fluid outlet 6.

  During filtration as described above, if the amount of foreign matter attached to the screen 12 of the filter element 3 is small, a large differential pressure does not occur in the pressure of the raw fluid at the fluid inlet 5 and the fluid outlet 6, so the differential pressure is set. Since the value is within the range, the differential pressure switch 19 is turned off as shown in FIG. 1, and the driving device 4 is kept in the lowered position of the filter element 3.

  When the raw fluid is filtered as described above and foreign matter adheres to the inner surface of the screen 12 in the filter element 3, the flow of the raw fluid passing through the screen 12 is deteriorated, and the filtration function is lowered. Therefore, when the pressure of the fluid at the fluid outlet 6 of the strainer body 2 decreases, a pressure difference between the raw fluids occurs at the fluid inlet 5 and the fluid outlet 6, and when this pressure difference exceeds a set value, As described above, the differential pressure switch 19 which is turned on by detecting the pressure difference activates the drive device 4 linked to the drive shaft 13 and pulls the filter element 3 from the filtration position to the cleaning position located in the upper inflow chamber 8. increase.

  As shown in FIG. 2, the filter element 3 in the cleaning position in the upper inflow chamber 8 has an upper end higher than the fluid inlet 5, and is located between the inner periphery of the upper inflow chamber 8 and the outer periphery of the flange 11. The gap is narrow, and the lower end of the filter element 3 that is in the cylindrical shape remains fitted to the inner diameter of the support wall 7, and the screen 12 is at the same height level as the fluid inlet 5.

  When the differential pressure switch 19 is turned on by detecting the pressure difference, when the valve 22 of the fluid introduction path 20 is closed, the valve 23 of the cleaning fluid introduction path 21 is simultaneously opened, and when the filter element 3 is pulled up to the cleaning position, As shown in FIG. 3 (b), the foreign matter discharge port 16 that has risen integrally is opened with the lower end opening away from the valve seat 18.

  For this reason, the flow of the cleaning fluid with respect to the filter element 3 moved to the cleaning position becomes a flow opposite to that at the time of filtration from the outside toward the inside with respect to the screen 12. The foreign matter adhering to the film is peeled and removed.

  The cleaned dirty fluid generated inside the filter element 3 flows out from the foreign matter discharge port 16 connected to the lower part of the filter element 3 to the foreign matter discharge pipe 17 and does not flow out to the fluid outlet 6.

  In this way, the cleaning fluid is allowed to flow for a predetermined time, and when the screen 12 of the filter element 3 is back-washed to restore the filtration function, the differential pressure switch 19 is forcibly turned off.

  As a result, first, the valve 22 of the fluid introduction path 20 is opened and the valve 23 of the cleaning fluid introduction path 21 is closed at the same time, and the cleaned dirty fluid generated inside the filter element 3 by the raw fluid is transferred to the foreign matter discharge pipe 17. After the fluid is discharged and the dirty fluid is prevented from flowing into the path of the raw fluid, the driving device 4 is then actuated to lower the filter element 3 to the filtration position where the filter element 3 can be accommodated in the lower outlet chamber 9. If the lower end opening of the discharge port 16 is closed as shown in FIG. 3A, the raw fluid flows from the inside to the outside of the screen 12 of the filter element 3, and the fluid outlet from the lower outflow chamber 9 as shown in FIG. 6 returns to the normal filtration state.

  In the illustrated example, the backwashing strainer 1 is used alone. However, a plurality of backwashing strainers 1 may be installed in parallel to the fluid introduction path. Therefore, the filter element 3 can be back-washed, and there is an advantage that the flow of the fluid as a filter is not stopped.

DESCRIPTION OF SYMBOLS 1 Backflow washing | cleaning strainer 2 Strainer main body 3 Filter element 4 Drive apparatus 5 Fluid inlet 6 Fluid outlet 7 Support wall 8 Upper inflow chamber 9 Lower outflow chamber 10 Lid member 11 Flange 12 Screen 13 Drive shaft 14 Strut 15 Shaft coupling 16 Foreign matter discharge port 17 Foreign matter discharge pipe 18 Valve seat 19 Differential pressure switch 20 Fluid introduction path 21 Washing water introduction path 22 Valve 23 Valve

Claims (5)

The filter element is incorporated inside the strainer body through which the fluid flows so that the fluid can be moved between a filtration position of the fluid and a cleaning position where the flow of the fluid passing through the filter element flows in the opposite direction to the filtration time.
A backwashing strainer in which a drive shaft is connected to the filter element, the filter element is moved to a cleaning position by the drive shaft, and foreign matter adhering to the surface of the filter element is washed away by the backflow of fluid.   The foreign matter discharge port is provided at the bottom of the filter element, the foreign matter discharge port is closed when the filter element is in the filtering position, and the foreign matter discharge port is opened when the filter element is in the cleaning position. Backwashing strainer.   A differential pressure switch is connected to the fluid inlet and the fluid outlet of the strainer body, the fluid inlet path and the washing water inlet path are switchably connected to the fluid inlet of the strainer body, and foreign matter adheres to the surface of the filter element. When a pressure difference equal to or greater than the value is generated, the continuity of the fluid inlet of the strainer body is switched from the fluid introduction path to the washing water introduction path by the differential pressure switch, and at the same time, the drive device linked with the drive shaft is activated. The backflow cleaning strainer according to claim 1 or 2, wherein the filter element is moved from the filtration position to the cleaning position.   The backflow cleaning strainer according to any one of claims 1 to 3, wherein the screen as a surface path member of the filter element is formed of any one of a metal material, a synthetic resin material, and a cloth material.   A backwashing strainer apparatus using the backwashing strainer according to claim 3, wherein a plurality of backwashing strainers are installed in parallel to the fluid introduction path, and the filter elements are backwashed alternately during the filtration operation.

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