JP2004084688A - Filter device of sealing gas - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a filter device which sufficiently maintaining cleanliness even in the case of buffer gas containing much liquid part without greatly remodeling the situation around the device. <P>SOLUTION: The flow path 7 of buffer gas from an inflow port 70 to an outflow port 79 is formed in a container 2. Two cylindrical filter elements 5 dividing the flow path into an upstream side and a downstream side are arranged in series in the longitudinal direction along the flow path 7, and the buffer gas is sequentially cleaned with respective elements. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a filter device suitable for purifying a sealing gas introduced into a non-contact mechanical seal.
[0002]
[Prior art]
A non-contact mechanical seal for sealing between a rotary shaft and a casing in a compressor or the like has already been provided, and a dry gas seal for directly sealing gas has been applied to many rotary machines including a centrifugal compressor.
FIG. 5 shows an example of such a case, in which a mating ring 102 hermetically sealed to a rotating shaft 100 and a primary ring 103 hermetically mounted on a seal housing 104 and urged in the axial direction by a pressing means 105 face each other. A sealing portion 106 (107) is formed by the sealing surfaces 102a and 103a, and a plurality of spiral grooves having an advancing angle with respect to the relative rotation direction are formed on one of the sealing surfaces 102a and 103a in the circumferential direction. A fixed pressure is provided between the sealing surfaces 102a and 103a, and a dynamic pressure toward the center is generated. This dynamic pressure generates a micron-unit gap between the two sealing surfaces so that a non-contact state is generated. This allows the high peripheral speed rotation to be maintained.
[0003]
The illustrated non-contact mechanical seal B is called a tandem type and has a seal cartridge in which two seal portions 106 and 107 are arranged side by side. The side seal portion 107 (auxiliary seal portion) restricts the leak gas from flowing directly to the atmosphere side.
The sealed fluid (buffer gas) supplied to the seal portion 106 is introduced through the conduit 108 and is discharged from the inside labyrinth 112 to the inside of the machine to prevent the inboard gas from entering. The leak gas that has passed is guided from the intermediate chamber 111 to a not-shown exhaust pipe such as a flare via a conduit 109.
A purge gas is supplied to the atmosphere-side labyrinth 113 from the conduit 110 to prevent entry of mist or the like of lubricating oil from bearings or the like on the atmosphere side and leakage gas to the atmosphere.
[0004]
The buffer gas supplied to the seal portion 106 needs to be a clean gas free of foreign matter and liquid. In particular, the liquid component in the gas enters the sealing surfaces 102a and 103a to generate heat on the sealing surfaces, and the heat causes the gap on the outer diameter side of the sealing surface to widen, thereby causing a problem that the leak gas flow rate increases. For this reason, the filter section A is provided in the buffer gas introducing pipe 108, and when there is a high possibility that the gas to be handled is accompanied by a liquid component, a coalescing type element having a high filtration accuracy and a liquid component removing performance. Is used.
[0005]
[Problems to be solved by the invention]
By the way, when the compressed gas of the compressor to be sealed is used as the buffer gas, since a large amount of liquid is contained in the gas, sufficient cleanliness can be obtained simply by passing one filter through the filter part A. I can't. As a countermeasure for this, it is possible to increase the element size to reduce the flow velocity of the element and improve the trapping efficiency, or to connect two filter devices 101 each having the element 5 in series as shown in FIG. Have been tried.
[0006]
However, there is a limit to the increase in the element size, and the measures connected in series can reduce the influence of the liquid content of the buffer gas, but the condition of the device around the filter device 101 is largely reduced mainly because of the installation space. It needed to be remodeled and was not a practical solution.
[0007]
The present invention has been made in view of the current situation, and it is necessary to provide a filter device that can ensure sufficient cleanliness even when a large amount of liquid is contained in a buffer gas without significantly modifying the surroundings of the device. Is what you do.
[0008]
[Means for Solving the Problems]
That is, the present invention is a filter device for preliminarily filtering or removing a sealing gas supplied to a non-contact mechanical seal forming a dry gas seal and purifying the gas, and a container having an inlet and an outlet. Inside, while forming a flow path of the sealing gas from the inlet to the outlet, a plurality of filter elements for dividing the flow path into an upstream side and a downstream side are arranged in series along the flow path. And a sealing gas filter device characterized in that the sealing gas is sequentially cleaned by each element.
[0009]
In such a filter device, a cleaning effect equivalent to or more than the conventional usage in which two single-element structure filter devices are connected in series can be expected, and the two devices are connected in series. In such a case, an increase in installation space and a corresponding remodeling around the device are avoided.
[0010]
In the cylindrical container, an upper circulation space and a lower circulation space which are communicated with each other via a flow path are provided, and a cylindrical filter element which allows a sealing gas to pass in a radial direction is provided in each of these circulation spaces. In the case of being arranged on a straight line, a compact structure is maintained.
[0011]
In the case where each filter element is the same kind of element, the second-stage element functions similarly as a backup even if the element is clogged and broken due to a large amount of particles in the gas and the captured particles, Dry gas seal is reliably protected.
[0012]
The filter element is a cylindrical coalescer type filter element that passes a sealing gas from a radially inner side to an outer side and captures a liquid component in the gas, wherein the inflow port is disposed in an upper circulation space. While communicating with the inner flow path, the element outer flow path of the upper circulation space is communicated with the inner flow path of the element disposed in the lower circulation space, and the outlet is communicated with the element outer flow path of the lower circulation space, In the case where the bottom has a drain outlet that communicates with the outside flow path of the element, unlike the conventional case where two units are connected in series, the drain captured by the upper element is guided to the lower part along the gas flow. Drains are prevented from staying in or entraining in the upper circulation space, and the amount of drain removed is smaller than that of the conventional two-unit connection method. It can be increased to.
[0013]
For the opening on the inner surface side of the container that communicates with the outlet, a concave portion that forms a flow space between the inner wall of the main body and the outer surface side is provided, and at a height different from the opening of the flow restricting member, A substantially cylindrical flow regulating member having a perforated portion for introducing a processing gas into the flow space from the element outside flow path is covered, and the fluid passing through the element flows through the perforated portion. After being introduced into the space, and once circulated in the axial direction along the inner surface of the container, and discharged from the outlet, it is possible to prevent a slight mist or drain passing through the element from reaching the outlet as much as possible. Even if the element is damaged, fragments are prevented from entering the opening.
[0014]
Discharging means for discharging a part of the clean gas passing through the element through the drain discharge port is provided, and the flow of the discharged clean gas guides the drain adhered to the inner surface of the container to the discharge port. It is possible to prevent the drain adhering to the gas from being led to the outlet by the flow of the gas, and the trapped drain can be reliably removed.
[0015]
The container includes a cylindrical container body in which the lower circulation space is formed on the inner surface side and an inlet and an outlet formed in an outer peripheral wall, and a cylindrical lid in which the upper circulation space is formed on the inner surface side. In the one that is composed of a body and is fixed to each other by bolts penetrating through the flanges formed at the respective open ends, the element can be easily replaced, and the upper element is removed as necessary, and Alternatively, for example, by attaching a plate-shaped member, the configuration can be easily changed to a compact filter device having a single element structure.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0017]
FIG. 1 is an explanatory view showing the internal structure of a filter device of the present invention. FIGS. 1 to 5 show an embodiment, in which reference numeral 1 denotes a filter device, 2 denotes a container, 5 denotes a filter element, and 7 denotes a flow path. Are respectively shown.
[0018]
As shown in FIG. 5, the filter device 1 according to the present invention filters or separates a sealing gas supplied to the sealing portion 106 of the non-contact mechanical seal B forming a dry gas seal in advance, as shown in FIG. In this embodiment, the non-contact mechanical seal B is a compressor shaft sealing device, and the filter device 1 purifies a buffer gas, which is a sealing gas.
As shown in FIG. 1, the filter device 1 forms a buffer gas flow path 7 from the inflow port 70 to the outflow port 79 in a vessel 2 having an inflow port 70 and an outflow port 79, and Conventionally, a plurality of filter elements 5 for dividing a passage into an upstream side and a downstream side are arranged in series along the flow path 7, and the buffer gas is sequentially cleaned by each element. While a cleaning effect equal to or more than that of the method of using is obtained, the installation space can be made more compact than before.
[0019]
Note that FIG. 5 shows a tandem type non-contact mechanical seal in which the pair of the mating ring 102 and the primary ring 103 is two pairs in the axial direction. Alternatively, the sealing surfaces 102a and 103a may be brought into contact with each other for sealing.
[0020]
Two filter devices 1 (A) are mounted in parallel on the buffer gas supply pipe, and are alternately used for operation and standby by operating a valve. That is, when the operation is clogged, the spare is switched to the operation, and the clogged element is replaced with a new one, which becomes the spare. The filter unit A is provided with a differential pressure switch that operates with a differential pressure gauge and operates to increase the pressure. As soon as the clogging of the element is detected, the filter is switched to a spare filter so that the filter can be replaced without stopping operation. I have.
[0021]
The container 2 has a vertically long cylindrical shape, and an upper circulation space 24 and a lower circulation space 25 communicating with each other via a flow passage 74 are vertically provided in the container.
Specifically, an inflow pipe 26 and an outflow pipe 27 are protruded from the outer peripheral wall, and a cylindrical container body 21 having a lower circulation space 25 inside, and a cylindrical container body having an upper circulation space 24 inside. The lid 22 is detachably assembled to each other with bolts and nuts penetrating through the flanges 21a, 22a formed at the respective open ends. Cylindrical filter elements 5 that pass through and capture foreign substances and liquid components are arranged on the same straight line, thereby internally forming an upper and lower two-stage element structure.
[0022]
With such a flange structure, for example, as shown in FIG. 2, the upper element 5 is removed, and the plate member 23 is fixed to the flange 21a instead of the lid 22 with a bolt and a nut as in the conventional case. The configuration can be easily changed to the filter device 1A composed of a single element, and the configuration can be made compact by changing the configuration according to the use environment such as when high filtration accuracy is not required.
[0023]
The type of the filter elements 5, 5 arranged in series vertically can be selected as appropriate according to the use environment. In this example, the use of the same type of element causes the upstream element, which is the first stage, to be clogged and clogged by trapped particles. Even if a breakage occurs, the same function is secured by using the downstream element as a backup, and the dry gas seal is reliably protected.
In addition, a filter having a smaller filtration than the upper side is used for the lower side which is the second stage, or a filter element other than the coalescer type is used for the upper side and a coalescer type for capturing moisture is used for the lower side. Of course, it is also possible to use a combination of different kinds of elements.
[0024]
For the upper and lower elements, a cylindrical coalescer type filter element 5 for passing a buffer gas from a radially inner side to an outer side and capturing a liquid component in the gas is used.
In this embodiment, since the buffer gas to be cleaned is the compressed gas of the compressor, the element has a two-layer structure with a coalescing function of micro glass fiber and resin material, an inner diameter of 50.8 mm and a thickness of 6 mm. An element having a removal efficiency of 93% with a diameter of 0.4 mm, a length of 230 mm, a particle diameter of 0.1 μm, and a removal efficiency of 100% with a particle diameter of 5 μm is suitably used.
[0025]
Near the upper end of the container body 21, an upper flow space 24 and a lower flow space 25 formed internally by combination with the lid 22 are divided, and support ends 31 and 32 of the elements are provided at upper and lower ends, respectively. A flat cylindrical support member 3 is fitted inside.
One end of a support rod 8 having screw grooves 81 and 82 formed at both ends of the support member 3 is screwed into a central portion of the support end portion 31 (32) to stand upright. The one end 5a of the element is engaged with the formed step 33 so as to be coaxial with the support rod 8, and a fastening member 83 engaged with the other end 5b of the element is screwed into the screw groove 82 at the tip of the support rod. By doing so, the element 5 is fixed to the support end 31 via the support rod 8 and the fastening member 83.
[0026]
The outer peripheral surface of the support member 3 is provided with a concave groove 30 forming an annular space between the support member 3 and the inner wall of the main body, and the inflow pipe 26 is provided at a position communicating with the annular space. Further, the support member 3 has a flow passage 71 which is opened at the bottom surface of the concave groove 30 and communicates with the upper element inner flow passage 72 substantially at the center of the upper end. The buffer gas guided from the inflow port 70 is guided to the inside flow path 72 of the upper element 5 through the flow path 71, and then passes through the element 5 in the radial direction to be filtered and purified.
[0027]
Similarly, in the support member 3, a flow path 74 that opens to the upper element outer flow path 73 and communicates with the lower element inner flow path 75 is formed obliquely downward, and the element outer flow path 76 of the lower flow space 25 is formed. Is provided with an outflow pipe 27, and the buffer gas passing through the upper element is guided to the inner flow path of the lower element through the flow path 74, passes through the element 5 in the radial direction, and is filtered again. After being cleaned, it is discharged from the element outside flow path 76 through the outflow pipe 27.
In the present invention in which two elements are arranged in series in the vertical direction as described above, the drain captured by the upper element is guided to the lower part through the flow passage 74 by the flow of the gas, and the drain liquid passes through the lower element when passing through the lower element. By taking small drain droplets, the amount of drain that cannot be captured by the lower element is reduced. As a result, the amount of the drain liquid itself to be removed also increases, so that stagnation and entrainment of the drain are prevented.
[0028]
A cylindrical flow restricting member 4 having a concave portion 40 that forms a flow space with the inner wall of the main body on the outer surface side is covered by a portion facing the inner surface opening 79a of the outflow pipe 27 on the inner surface side of the container main body 21. At a position different from the inner surface opening 79a of the flow restricting member 4, a porous portion 41 for introducing a buffer gas into the flow space from the element outer flow path 76 is formed. Since the introduced buffer gas is discharged from the outflow pipe 27 after being once circulated in the axial direction along the inner surface of the container, a slight mist that has passed through the element by the flow restricting member forming the detour flow path, Drain is prevented from directly entering the outflow pipe 27 as much as possible, and even if the element is damaged, the debris is prevented from entering the outflow pipe 27.
[0029]
A drain pipe 28 having a drain outlet 90 is provided at the bottom of the main body container 21. In this example, a drain pot 9 with a liquid level meter LG is connected as shown in FIG. Drain is continuously discharged. As shown in FIG. 4, a discharging means for discharging a small amount of gas from a drain pot to an exhaust pipe such as a flare through a throttle section 91 and discharging a part of the buffer gas passing through the element through the drain discharge port 90. The drain attached to the inner surface of the container is forcibly guided to the outlet by the flow of the small amount of the buffer gas discharged, and the drain remains in the inside and enters the outflow pipe 27. Thus, the liquid can be reliably guided to the drain pot.
[0030]
The conduit 108 on the downstream side of the filter device 1 is heated by steam lines, and is subjected to steam trace heat retention for evaporating a liquid component, thereby radiating heat from the piping surface and controlling the flow rate at an orifice, a regulating valve and the like. Mist formation and drainage due to a temperature drop due to the adiabatic expansion action are prevented, and it is preferable that the outflow pipe 27 of the filter device 1 is also kept warm.
[0031]
【The invention's effect】
As described above, according to the filter device of the present invention, even in an operating condition in which a large amount of liquid is present in the buffer gas, the conventional use method in which two single-element structure filter devices are connected in series The same or higher cleaning effect can be expected, and the leak gas flow rate can be stabilized, and the installation space in the conventional case where the two units are connected in series and the accompanying significant modification around the device are avoided. Is done.
[0032]
In the cylindrical container, an upper circulation space and a lower circulation space which are communicated with each other via a flow path are provided, and a cylindrical filter element which allows a sealing gas to pass in a radial direction is provided in each of these circulation spaces. Since they are arranged on a straight line, a compact structure can be maintained.
[0033]
Since each filter element is the same type of element, if the gas contains a large amount of particles and the element is clogged and damaged by the captured particles, the second-stage element can function as a backup and operate in the same manner. The gas seal can be reliably protected.
[0034]
The filter element is a cylindrical coalescer type filter element that passes the sealing gas from the radially inner side to the outer side and captures a liquid component in the gas, wherein the inflow port is disposed in the upper circulation space. While communicating with the flow path, the element outer flow path of the upper circulation space is communicated with the inner flow path of the element arranged in the lower circulation space, the outlet is communicated with the element outer flow path of the lower circulation space, and the container bottom is Also, unlike the conventional one connected in series, the drain caught by the upper element is guided to the lower part along the gas flow, so that the drain outlet communicating with the element outside flow path is provided. Drainage can be prevented from being retained or entrained in the space, and the amount of drain removed can be further increased compared to the conventional two-unit connection method. .
[0035]
For the opening on the inner surface side of the container that communicates with the outlet, a concave portion that forms a flow space between the inner wall of the main body and the outer surface side is provided, and at a height different from the opening of the flow restricting member, A substantially cylindrical flow regulating member having a perforated portion for introducing a processing gas from the element outer flow path into the flow space is covered, and the fluid passing through the element flows through the perforated portion. After being led to the space, and once circulated in the axial direction along the inner surface of the container, and then discharged from the outlet, it is possible to prevent a slight mist or drain passing through the element from reaching the outlet as much as possible. Even if the element is damaged, the fragments can be prevented from entering the opening.
[0036]
Discharge means for discharging a part of the clean gas passing through the element through the drain outlet is provided, and the flow of the discharged clean gas guides the drain attached to the inner surface of the container to the outlet. It is possible to prevent the drain adhering to the gas from being led to the outlet by the flow of the gas, and to reliably remove the trapped drain.
[0037]
The container includes a cylindrical container body in which the lower circulation space is formed on the inner surface side and an inlet and an outlet formed in an outer peripheral wall, and a cylindrical lid in which the upper circulation space is formed on the inner surface side. And the lids are fixed to each other by bolts penetrating through the flanges formed at the respective open ends, so that the elements can be easily exchanged, and the upper element is removed as necessary, and the lid For example, by attaching a plate-shaped member instead of the above, the configuration can be easily changed to a compact filter device having a single element structure.
[Brief description of the drawings]
FIG. 1 is a sectional view showing an internal structure of a filter device according to an embodiment of the present invention.
FIG. 2 is a sectional view showing a state where the configuration is changed to a single element structure.
FIG. 3 is an explanatory view showing a drain pot connected to a discharge pipe.
FIG. 4 is an explanatory view showing a discharge means for discharging a part of a buffer gas from a drain discharge port.
FIG. 5 is an explanatory view showing a non-contact mechanical seal and a filter unit.
FIG. 6 is a sectional view showing an example in which two conventional filter devices having a single element structure are connected in series.
[Explanation of symbols]
Reference Signs List A Filter part B Non-contact mechanical seal 1 Filter device 2 Container 3 Support member 4 Flow control member 5 Element 5a End 5b End 7 Flow path 8 Support rod 9 Drain pot 21 Container main body 21a Flange 22 Lid 22a Flange 23 Plate shape Member 24 Flow space 25 Lower flow space 26 Inflow pipe 27 Outflow pipe 28 Drain pipe 30 Concave groove 31 Supporting end 32 Supporting end 33 Step 40 Depression 41 Perforated part 70 Inlet 71 Flow passage 72 Inside flow path 73 Outside Flow path 74 Flow path 75 Inner flow path 76 Outer flow path 79 Outlet 79a Inner opening 81, 82 Screw groove 83 Fastening member 90 Drain discharge port 91 Restrictor 100 Rotating shaft 101 Filter device 102a Le surface 102 mating ring 103a seal face 103 primary ring 105 pushing means 104 seal housing 106 seal portion 107 sealing portion 108 guide pipe 109 guiding pipe 110 guiding pipe 111 intermediate chamber 112 Labyrinth 113 Labyrinth

Claims (7)

A filter device for preliminarily filtering or removing a sealing gas supplied to a non-contact mechanical seal forming a dry gas seal and for purifying the gas, and the filter is provided in a container having an inlet and an outlet. While forming a flow path of the sealing gas from an inlet to an outlet, a plurality of filter elements for dividing the flow path into an upstream side and a downstream side are arranged in series along the flow path. A gas filter device for sealing, wherein gas is sequentially purified by each element. In the cylindrical container, an upper circulation space and a lower circulation space which are communicated with each other via a flow path are provided, and a cylindrical filter element which allows a sealing gas to pass in a radial direction is provided in each of these circulation spaces. The filter device according to claim 1, wherein the filter device is arranged on a straight line. 3. The filter device according to claim 1, wherein each of the filter elements is of the same type. The filter element is a cylindrical coalescer type filter element that passes a sealing gas from a radially inner side to an outer side and captures a liquid component in the gas, wherein the inflow port is disposed in an upper circulation space. While communicating with the inner flow path, the element outer flow path of the upper circulation space is communicated with the inner flow path of the element arranged in the lower circulation space, and the outlet is communicated with the element outer flow path of the lower circulation space, 4. The filter device according to claim 2, wherein a drain outlet communicating with the element outside flow path is provided at the bottom. For the opening on the inner surface side of the container that communicates with the outlet, a concave portion that forms a flow space between the inner wall of the container and the outer surface side is provided, and at a different height from the opening of the flow restricting member, A substantially cylindrical flow regulating member having a perforated portion for introducing a processing gas from the element outer flow path into the flow space is covered, and the fluid passing through the element flows through the perforated portion. The filter device according to claim 4, wherein the filter device is led to a space, once circulated in the axial direction along the inner surface of the container, and then discharged from the outlet. 5. A discharge means for discharging a part of the clean gas passing through the element through the drain discharge port, and the drain attached to the inner surface of the container is guided to the discharge port by the flow of the discharged clean gas. Filter device. The container includes a cylindrical container body in which the lower circulation space is formed on the inner surface side and an inlet and an outlet formed in an outer peripheral wall, and a cylindrical lid in which the upper circulation space is formed on the inner surface side. The filter device according to any one of claims 2 to 6, comprising a body and fixed to each other by bolts penetrating flanges formed at the respective open ends.

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