US20060198743A1 - Pump device - Google Patents
Pump device Download PDFInfo
- Publication number
- US20060198743A1 US20060198743A1 US11/069,983 US6998305A US2006198743A1 US 20060198743 A1 US20060198743 A1 US 20060198743A1 US 6998305 A US6998305 A US 6998305A US 2006198743 A1 US2006198743 A1 US 2006198743A1
- Authority
- US
- United States
- Prior art keywords
- blocking flow
- blocking
- rotational shaft
- pump device
- discharge section
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 230000000903 blocking effect Effects 0.000 claims abstract description 177
- 239000007788 liquid Substances 0.000 claims abstract description 41
- 230000007246 mechanism Effects 0.000 claims abstract description 39
- 239000010419 fine particle Substances 0.000 claims abstract description 14
- 238000007599 discharging Methods 0.000 claims abstract description 8
- 229910021642 ultra pure water Inorganic materials 0.000 description 22
- 239000012498 ultrapure water Substances 0.000 description 22
- 239000002184 metal Substances 0.000 description 9
- 230000003628 erosive effect Effects 0.000 description 7
- 229910021645 metal ion Inorganic materials 0.000 description 7
- 239000000919 ceramic Substances 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 230000001105 regulatory effect Effects 0.000 description 4
- 239000004065 semiconductor Substances 0.000 description 4
- 150000002500 ions Chemical class 0.000 description 3
- 239000008399 tap water Substances 0.000 description 3
- 235000020679 tap water Nutrition 0.000 description 3
- 238000011010 flushing procedure Methods 0.000 description 2
- 230000010354 integration Effects 0.000 description 2
- 239000004973 liquid crystal related substance Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 2
- 229910010271 silicon carbide Inorganic materials 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000004381 surface treatment Methods 0.000 description 2
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 1
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000010828 elution Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 239000010687 lubricating oil Substances 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/08—Sealings
- F04D29/10—Shaft sealings
- F04D29/106—Shaft sealings especially adapted for liquid pumps
- F04D29/108—Shaft sealings especially adapted for liquid pumps the sealing fluid being other than the working liquid or being the working liquid treated
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/08—Sealings
- F04D29/10—Shaft sealings
- F04D29/12—Shaft sealings using sealing-rings
- F04D29/126—Shaft sealings using sealing-rings especially adapted for liquid pumps
- F04D29/128—Shaft sealings using sealing-rings especially adapted for liquid pumps with special means for adducting cooling or sealing fluid
Definitions
- the present invention relates to a rotary pump device for transporting a very highly-purity active liquid for use in a process of fabricating semiconductor devices, liquid crystals, etc., and more particularly to a pump device which is capable of preventing metal ions and other fine particles from being produced by isolating an active liquid, such as ultrapure water or the like, and a metallic part of a pump mechanism from each other.
- the concentration of metal ions which remain in ultrapure water, poses a large problem.
- the content of metal ions is required to be 1 PPT (Part Per Trillion) or less.
- Metal ions are caused to occur when ultrapure water dissolves a metal in liquid-contacting regions of devices including pumps, pipes, valves, etc. in a wet process. It is understood that ultrapure water of highest purity having a resistance of 18.20 M ⁇ or higher tends to elute highly active ions of metal or the like.
- a pump device has an impeller rotatable in a pump space, a rotational shaft interconnecting a rotational drive source and the impeller, a rotational shaft casing having a bearing assembly and/or a seal assembly, a first blocking flow mechanism, having a discharge section for discharging a portion of a main delivery liquid introduced from the pump space as a first blocking flow, for preventing a second blocking flow containing fine particles produced by the bearing assembly and/or the seal assembly from being entrained into the main delivery liquid, and a second blocking flow mechanism for combining the second blocking flow with the first blocking flow and discharging the second blocking flow from the discharge section while preventing the first blocking flow from being introduced.
- the first blocking flow mechanism has a first blocking flow passage defined between the rotational shaft and an inner circumferential surface of the rotational shaft casing
- the second blocking flow mechanism has a second blocking flow passage defined between the rotational shaft and an inner circumferential surface of the rotational shaft casing, the first blocking flow passage and the second blocking flow passage being disposed in respective positioned on both sides of the discharge section, the second blocking flow passage being supplied with an inactive liquid as the second blocking flow from a second blocking flow supply port which is open into the second blocking flow passage.
- the discharge section comprises a blocking disk mounted on the rotational shaft and a disk chamber defined in the rotational shaft casing and housing the blocking disk therein.
- a labyrinth is provided in the disk chamber between an inner circumferential surface of the disk chamber and the blocking disk.
- the second blocking flow preferably has a higher liquid pressure than the first blocking flow at the second blocking flow supply port.
- the second blocking flow passage is preferably filled at all times with the inactive liquid supplied from the second blocking flow supply port.
- the first blocking flow is preferably discharged from the discharge section at a rate higher than the second blocking flow, the rate of the second blocking flow being at least 1.5 when the rate of the first blocking flow is 1 .
- FIG. 1 is a cross-sectional view of a pump device according to an embodiment of the present invention.
- FIG. 2 is a cross-sectional view of a pump device according to another embodiment of the present invention.
- a pump device has regions, other than rotary sliding components, such as a bearing assembly and a seal assembly in a rotational shaft casing, which are brought into contact with a main delivery liquid (ultrapure water) and which have surfaces treated for erosion resistance by a lining of tetrafluororesin or the like.
- a main delivery liquid ultrapure water
- a first blocking flow as a portion of a main delivery liquid (ultrapure water) flowing from a pump space into the rotational shaft casing is discharged out of the rotational shaft casing through a first blocking flow passage defined between a rotational shaft and an inner circumferential surface of the rotational shaft casing, a discharge section contiguous to the first blocking flow passage and disposed in the rotational shaft casing closely to an impeller, and a discharge passage communicated with the discharge section. Therefore, a second blocking flow containing fine particles produced from the rotary sliding components, such as the bearing assembly and the seal assembly, as they are worn is blocked by the first blocking flow against entry from the rotational shaft casing into the pump space.
- an inactive liquid such as ordinary tap water, which exhibits an excellent lubricity to ultrapure water, flows as the second blocking flow from a supply source into the rotational shaft casing, and then flows through a second blocking flow passage defined between the rotational shaft and an inner circumferential surface of the rotational shaft into the discharge section of the first blocking flow mechanism. Therefore, the first blocking flow is prevented from entering into the rotary sliding components, such as the bearing assembly and the seal assembly.
- the inactive liquid (water) delivered as the second blocking flow into the rotational shaft casing flows along the rotational shaft away from the first blocking flow mechanism, i.e., toward the rotary sliding components, such as the bearing assembly and the seal assembly.
- the inactive liquid fills the rotational shaft casing including the rotary sliding components, such as the bearing assembly and the seal assembly, isolating the first blocking flow (ultrapure water) and the rotary sliding components from each other.
- the pressure of the second blocking flow of the inactive liquid at a second blocking flow supply port is higher than the pressure of the first blocking flow.
- the rate of the second blocking flow may be lower than the rate of the first blocking flow at all times, primarily at a level for allowing the second blocking flow to operate as lubricating oil and exhibit a cooling effect. Since the rate of the second blocking flow after it has flowed into the rotational shaft casing is much lower than the rate of the first blocking flow, the pressure of the second blocking flow is gradually lowered toward the pressure of the first blocking flow, and becomes equal to the pressure of the first blocking flow when the second blocking flow is discharged in combination with the first blocking flow. Consequently, the second blocking flow does not flow toward and into the pump space on the impeller side.
- the inactive liquid (water), which forms the second blocking flow, is supplied by a diaphragm that is actuatable pneumatically, hydraulically or electrically, or a metering pump comprising a plunger pump that is actuatable by an air cylinder. Tap water having a suitable pressure may also be used as the inactive liquid.
- a supply passage interconnecting the supply source and the rotational shaft casing may have a pressure regulating valve, a flow regulating valve, an on-off valve, and the like.
- FIG. 1 is a cross-sectional view of a pump device according to an embodiment of the present invention.
- the pump device has an impeller 2 rotatable in a pump space 1 , a rotational shaft 3 interconnecting a rotational drive source M and the impeller 2 , and a rotational shaft casing 4 having a bearing assembly B and a mechanical seal assembly S.
- the mechanical seal assembly S has a fixed ring S 1 and a rotary ring S 2 . Regions of the various components, other than the bearing assembly B and the mechanical seal assembly S, which are brought into contact with ultrapure water as a main delivery liquid, are treated for erosion resistance by a lining of tetrafluororesin or the like. The regions, which are treated for erosion resistance, are indicated by bold solid lines in FIG. 1 .
- the rotational shaft casing 4 has a disk chamber 5 a defined therein by an inner circumferential surface thereof and positioned between the impeller 2 and the bearing assembly B.
- a blocking disk 5 b mounted on the rotational shaft 3 is rotatably housed in the disk chamber 5 a .
- the disk chamber 5 a and the blocking disk 5 b housed in the disk chamber 5 a and made of fluororesin, make up a discharge section 5 of a first blocking flow mechanism.
- the disk chamber 5 a communicates with a discharge passage 5 c having flow rate regulating mechanisms 5 e , 5 f .
- a labyrinth 5 d is provided between the inner circumferential surface of the disk chamber 5 a and the blocking disk 5 b . However, as shown in FIG. 2 , the labyrinth 5 d may be dispensed with.
- the first blocking flow mechanism is constructed of a first blocking flow passage 6 which is defined as a gap between the portion of the rotational shaft 3 extending from the pump space 1 to the disk chamber 5 a and the inner circumferential surface of the rotational shaft casing 4 , the discharge section 5 , and the discharge passage 5 c .
- the first blocking flow mechanism causes a branched flow of ultrapure water as the main delivery liquid to flow from the pump space 1 successively through the first blocking flow passage 6 , the discharge section 5 , and the discharge passage 5 c , preventing a liquid containing fine particles (a second blocking flow) from entering from the bearing assembly B and the mechanical seal assembly S into the pump space 1 .
- the pump device also has a supply source T of an inactive liquid (water), a metering pump P, a second blocking flow supply port 7 that is open at the inner circumferential surface of the rotational shaft casing 4 between the bearing assembly B and the mechanical seal assembly S, and a second blocking flow passage 8 which is defined as a gap between the portion of the rotational shaft 3 extending from the bearing assembly B to the disk chamber 5 a and the inner circumferential surface of the rotational shaft casing 4 .
- the supply source T, the metering pump P, the second blocking flow supply port 7 , and the second blocking flow passage 8 make up a second blocking flow mechanism.
- the second blocking flow supply port 7 of the second blocking flow mechanism is positioned behind the blocking disk 5 b disposed at a terminal end of the first blocking flow mechanism.
- An inactive liquid (water) supplied from the supply source T flows as a second blocking flow successively through the bearing assembly B, the second blocking flow passage 8 , the discharge section 5 , and the discharge passage 5 c , preventing the first blocking flow (ultrapure water) coming from the discharge section 5 of the first blocking flow mechanism from entering into the bearing assembly B.
- the second blocking flow is combined with the first blocking flow in the discharge section 5 of the first blocking flow mechanism, and flows out from the discharge passage 5 c .
- the discharge section 5 is made up of the disk chamber 5 a and the blocking disk 5 b , and the labyrinth 5 d is provided in the disk chamber 5 a , making it difficult for the blocking blows to combine with each other and allowing the blocking flows to flow as centrifugal flows due to the rotation of the blocking disk 5 b out from the discharge passage 5 c .
- the first blocking flow is thus fully prevented from entering into the bearing assembly B.
- the inactive liquid, which forms the second blocking flow maybe ordinary tap water, and is supplied under a higher pressure and at a lower rate than the first blocking flow to the second blocking flow passage 8 by the metering pump P. Since the second blocking flow flows under a high pressure and at a low rate, it is equalized in pressure to the first blocking flow in the discharge section 5 , and discharged out of the pump device through the flow rate regulating mechanisms 5 e , 5 f provided in the discharge passage 5 c .
- the ratio of the flow rates of the first and second blocking flows, which are combined with each other, may be 1.5:1, or 50:1 or 100:1 in some cases.
- the direction of the blocking flows is determined by the flow rate of the first blocking flow as a main flow.
- the second blocking flow supplied to the pump device can maintain a large discharge rate.
- the pump device If the pump device is inactivated for a long time, fine particles including metal ions produced from metal and ceramics of liquid-contacting regions brought into contact with the delivery liquid are entrained into the ultrapure water as the delivery liquid. Therefore, for achieving the ultrahigh purity of ultrapure water, whose metal ion concentration is required to be 1 PPT or less, immediately after the pump device has started to operate, it is necessary to clean the contaminated interior of the pump device with a large amount of flushing ultrapure water at the time the pump device starts to operate. However, the flushing process is responsible for an excessive increase in the running cost of the pump device.
- the second blocking flow mechanism is immediately inactivated to stop the second blocking flow containing fine particles of metal and ceramics.
- the main pump is operated again to circulate the first blocking flow at a rate, which is 1/10 or less of the ordinary rate, for thereby reliably preventing fine particles including eluted ions of metal and ceramics from entering into the pump space 1 .
- the second blocking flow mechanism is filled with the second blocking flow, the first blocking flow does not enter into the bearing assembly B.
- the second blocking flow mechanism may be operated continuously or intermittently at a rate which is 1 ⁇ 2 of the ordinary rate.
- a lip seal L 1 is provided as a check valve in the first blocking flow passage 6
- a lip seal L 2 is provided as a check valve in the second blocking flow passage 8 .
- FIG. 2 shows a pump device according to another embodiment of the present invention.
- the pump device shown in FIG. 2 is different from the pump device shown in FIG. 1 in that the bearing assembly B is dispensed with, and the rotary ring S 2 of the mechanical seal assembly S is positioned closer to the impeller 2 , with the second blocking flow support port 7 being open in the rotational shaft casing 4 between the blocking disk 5 b and the fixed ring S 1 of the mechanical seal assembly S.
- fine particles produced in the rotary sliding regions of the rotary pump are efficiently discharged at a low cost, the main delivery liquid is effectively prevented from entering into the rotary sliding regions, and fine particles, such as metal ions or the like, are prevented from being produced due to contact between the main delivery liquid, such as ultrapure water or the like, and the rotary sliding regions of the pump device.
- the present invention has been described above as having an outside-type mechanical seal having a fixed ring disposed in a pump chamber and a rotary ring and a spring disposed outside of the pump chamber.
- the present invention is also applicable to an inside-type mechanical seal mechanism having a rotary ring and a spring disposed in a pump chamber.
- the present invention is also applicable to a grand packing mechanism or a lip seal mechanism which is a rotary sliding seal mechanism other than the mechanical seal.
- a pump device for transporting ultrapure water or the like has a pump space, an impeller rotatable in the pump space, a rotational shaft interconnecting a rotational drive source and the impeller, and a rotational shaft casing having a bearing assembly and a seal assembly.
- the pump device has regions brought into contact with a main delivery liquid and treated for erosion resistance by a lining of tetrafluororesin or the like.
- the pump device also has a first blocking flow mechanism for preventing worn fine particles produced from rotary sliding components, such as the bearing assembly and the seal assembly, brought into contact with a second blocking flow, from being entrained into the delivery liquid, and a second blocking flow mechanism for preventing a main delivery liquid from entering from the pump space into regions, not treated for erosion resistance, of the rotary sliding components.
- the first blocking flow mechanism comprises a first blocking flow passage defined by the rotational shaft and an inner circumferential surface of the rotational shaft casing, a discharge section disposed in the rotational shaft casing closely to the impeller, for discharging a first blocking flow introduced as the main delivery liquid from the pump space into the rotational shaft casing, from the first blocking flow passage, and a discharge passage communicated with the discharge section.
- the second blocking flow mechanism comprises a supply source for supplying a inactive liquid, having a lubricity, as the second blocking flow, a second blocking flow passage for delivering the second blocking flow into the rotational shaft casing having the bearing assembly and the seal assembly positioned therein, the second blocking flow passage being defined by the rotational shaft and the inner circumferential surface of the rotational shaft casing, a second blocking flow supply port defined in the rotational shaft casing between an end of the rotational shaft closely to the rotary sliding components and the discharge passage, for combining the second blocking flow through the second blocking flow passage with the first blocking flow and discharging the second blocking flow from the discharge passage of the first blocking flow mechanism, and a supply passage disposed between the supply source and the second blocking flow supply port.
- the discharge section of the first blocking flow mechanism comprises a blocking disk mounted on the rotational shaft in an area where the opposite flows meet each other, and a disk chamber defined in the rotational shaft casing and housing the blocking disk therein.
- a labyrinth is preferably provided in the disk chamber for preventing the first blocking flow and the second blocking flow from flowing into the second blocking flow passage and the first blocking flow passage, respectively.
- the regions not treated for erosion resistance in the rotational shaft casing is preferably filled at all times with the second blocking flow of the inactive liquid flowing in from the second blocking flow supply port, for isolation from the main delivery liquid having a strong chemical attack tendency which is introduced from the first blocking flow passage.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Structures Of Non-Positive Displacement Pumps (AREA)
Abstract
A pump device has an impeller rotatable in a pump space, a rotational shaft interconnecting a rotational drive source and the impeller, a rotational shaft casing having a bearing assembly and/or a seal assembly, a first blocking flow mechanism, having a discharge section for discharging a portion of a main delivery liquid introduced from the pump space as a first blocking flow, for preventing a second blocking flow containing fine particles produced by the bearing assembly and/or the seal assembly from being entrained into the main delivery liquid, and a second blocking flow mechanism for combining the second blocking flow with the first blocking flow and discharging the second blocking flow from the discharge section while preventing the first blocking flow from being introduced.
Description
- 1. Field of the Invention
- The present invention relates to a rotary pump device for transporting a very highly-purity active liquid for use in a process of fabricating semiconductor devices, liquid crystals, etc., and more particularly to a pump device which is capable of preventing metal ions and other fine particles from being produced by isolating an active liquid, such as ultrapure water or the like, and a metallic part of a pump mechanism from each other.
- 2. Description of the Related Art
- For achieving a high level of integration of semiconductor devices, it is necessary to increase the purity of various liquids used in the fabrication process and, in particular, to achieve extremely lower content of impurities in those liquids. With regard to ultrapure water that is used in a cleaning process for semiconductor fabrication, the content of fine particles having a size of 0.1 micron poses a problem and greatly affects the yield of products. Particularly, it was a challenging task for pumps for transporting ultrapure water to prevent fine particles from being produced by the wear of rotary sliding components. The task has been achieved by the inventor of the present application as disclosed in Japanese patent No. 1807169, U.S. Pat. No. 5131806, or Japanese laid-open patent publication No. H3-26897.
- As the level of integration of semiconductor devices and the performance of liquid crystals further increase, however, the concentration of metal ions, which remain in ultrapure water, poses a large problem. Today, the content of metal ions is required to be 1 PPT (Part Per Trillion) or less. Metal ions are caused to occur when ultrapure water dissolves a metal in liquid-contacting regions of devices including pumps, pipes, valves, etc. in a wet process. It is understood that ultrapure water of highest purity having a resistance of 18.20 MΩ or higher tends to elute highly active ions of metal or the like.
- In order to solve the above disadvantage, it has been customary to apply a surface treatment, such as a lining or coating of tetrafluororesin, to regions of devices, such as pumps, that are brought into contact with ultrapure water. However, it is generally difficult to apply a surface treatment, such as a lining of tetrafluororesin, to rotary sliding components and seals of pumps. Even if very chemically stable, highly hard SiC (silicon carbide) is used for rotary sliding components and seals of pumps, it cannot fully prevent ultrapure water from dissolving the metal. At present, it has been attempted to use functional ultrapure water containing a small amount of ozone (O3) or hydrogen fluoride (HF). Use of functional ultrapure water, however, is problematic in that metal and ceramics are exposed to a chemical attack, causing the liquid-contacting regions in rotary sliding components of pumps, i.e., bearings and seals, to suffer erosion due to elution of metal and ceramics.
- A pump device according to the present invention has an impeller rotatable in a pump space, a rotational shaft interconnecting a rotational drive source and the impeller, a rotational shaft casing having a bearing assembly and/or a seal assembly, a first blocking flow mechanism, having a discharge section for discharging a portion of a main delivery liquid introduced from the pump space as a first blocking flow, for preventing a second blocking flow containing fine particles produced by the bearing assembly and/or the seal assembly from being entrained into the main delivery liquid, and a second blocking flow mechanism for combining the second blocking flow with the first blocking flow and discharging the second blocking flow from the discharge section while preventing the first blocking flow from being introduced.
- In a preferred aspect of the present invention, the first blocking flow mechanism has a first blocking flow passage defined between the rotational shaft and an inner circumferential surface of the rotational shaft casing, and the second blocking flow mechanism has a second blocking flow passage defined between the rotational shaft and an inner circumferential surface of the rotational shaft casing, the first blocking flow passage and the second blocking flow passage being disposed in respective positioned on both sides of the discharge section, the second blocking flow passage being supplied with an inactive liquid as the second blocking flow from a second blocking flow supply port which is open into the second blocking flow passage.
- Preferably, the discharge section comprises a blocking disk mounted on the rotational shaft and a disk chamber defined in the rotational shaft casing and housing the blocking disk therein. Further preferably, a labyrinth is provided in the disk chamber between an inner circumferential surface of the disk chamber and the blocking disk.
- The second blocking flow preferably has a higher liquid pressure than the first blocking flow at the second blocking flow supply port.
- The second blocking flow passage is preferably filled at all times with the inactive liquid supplied from the second blocking flow supply port.
- The first blocking flow is preferably discharged from the discharge section at a rate higher than the second blocking flow, the rate of the second blocking flow being at least 1.5 when the rate of the first blocking flow is 1.
-
FIG. 1 is a cross-sectional view of a pump device according to an embodiment of the present invention; and -
FIG. 2 is a cross-sectional view of a pump device according to another embodiment of the present invention. - A pump device according to an embodiment of the present invention has regions, other than rotary sliding components, such as a bearing assembly and a seal assembly in a rotational shaft casing, which are brought into contact with a main delivery liquid (ultrapure water) and which have surfaces treated for erosion resistance by a lining of tetrafluororesin or the like. In a first blocking flow mechanism, a first blocking flow as a portion of a main delivery liquid (ultrapure water) flowing from a pump space into the rotational shaft casing is discharged out of the rotational shaft casing through a first blocking flow passage defined between a rotational shaft and an inner circumferential surface of the rotational shaft casing, a discharge section contiguous to the first blocking flow passage and disposed in the rotational shaft casing closely to an impeller, and a discharge passage communicated with the discharge section. Therefore, a second blocking flow containing fine particles produced from the rotary sliding components, such as the bearing assembly and the seal assembly, as they are worn is blocked by the first blocking flow against entry from the rotational shaft casing into the pump space.
- Specifically, in a second blocking flow mechanism, an inactive liquid, such as ordinary tap water, which exhibits an excellent lubricity to ultrapure water, flows as the second blocking flow from a supply source into the rotational shaft casing, and then flows through a second blocking flow passage defined between the rotational shaft and an inner circumferential surface of the rotational shaft into the discharge section of the first blocking flow mechanism. Therefore, the first blocking flow is prevented from entering into the rotary sliding components, such as the bearing assembly and the seal assembly. In the rotational shaft casing, the inactive liquid (water) delivered as the second blocking flow into the rotational shaft casing flows along the rotational shaft away from the first blocking flow mechanism, i.e., toward the rotary sliding components, such as the bearing assembly and the seal assembly. Since a terminal end of the rotational shaft casing, i.e., the end thereof close to a rotational drive source, is sealed by a seal mechanism, the inactive liquid (water) fills the rotational shaft casing including the rotary sliding components, such as the bearing assembly and the seal assembly, isolating the first blocking flow (ultrapure water) and the rotary sliding components from each other.
- The pressure of the second blocking flow of the inactive liquid at a second blocking flow supply port is higher than the pressure of the first blocking flow. However, the rate of the second blocking flow may be lower than the rate of the first blocking flow at all times, primarily at a level for allowing the second blocking flow to operate as lubricating oil and exhibit a cooling effect. Since the rate of the second blocking flow after it has flowed into the rotational shaft casing is much lower than the rate of the first blocking flow, the pressure of the second blocking flow is gradually lowered toward the pressure of the first blocking flow, and becomes equal to the pressure of the first blocking flow when the second blocking flow is discharged in combination with the first blocking flow. Consequently, the second blocking flow does not flow toward and into the pump space on the impeller side.
- The inactive liquid (water), which forms the second blocking flow, is supplied by a diaphragm that is actuatable pneumatically, hydraulically or electrically, or a metering pump comprising a plunger pump that is actuatable by an air cylinder. Tap water having a suitable pressure may also be used as the inactive liquid. If necessary, a supply passage interconnecting the supply source and the rotational shaft casing may have a pressure regulating valve, a flow regulating valve, an on-off valve, and the like.
- Embodiments of the present invention will be described in detail below with reference to the drawings.
FIG. 1 is a cross-sectional view of a pump device according to an embodiment of the present invention. - As shown in
FIG. 1 , the pump device has animpeller 2 rotatable in a pump space 1, arotational shaft 3 interconnecting a rotational drive source M and theimpeller 2, and arotational shaft casing 4 having a bearing assembly B and a mechanical seal assembly S. The mechanical seal assembly S has a fixed ring S1 and a rotary ring S2. Regions of the various components, other than the bearing assembly B and the mechanical seal assembly S, which are brought into contact with ultrapure water as a main delivery liquid, are treated for erosion resistance by a lining of tetrafluororesin or the like. The regions, which are treated for erosion resistance, are indicated by bold solid lines inFIG. 1 . - The
rotational shaft casing 4 has adisk chamber 5 a defined therein by an inner circumferential surface thereof and positioned between theimpeller 2 and the bearing assembly B. A blockingdisk 5 b mounted on therotational shaft 3 is rotatably housed in thedisk chamber 5 a. Thedisk chamber 5 a and the blockingdisk 5 b, housed in thedisk chamber 5 a and made of fluororesin, make up adischarge section 5 of a first blocking flow mechanism. Thedisk chamber 5 a communicates with adischarge passage 5 c having flowrate regulating mechanisms labyrinth 5 d is provided between the inner circumferential surface of thedisk chamber 5 a and the blockingdisk 5 b. However, as shown inFIG. 2 , thelabyrinth 5 d may be dispensed with. - The first blocking flow mechanism is constructed of a first
blocking flow passage 6 which is defined as a gap between the portion of therotational shaft 3 extending from the pump space 1 to thedisk chamber 5 a and the inner circumferential surface of therotational shaft casing 4, thedischarge section 5, and thedischarge passage 5 c. The first blocking flow mechanism causes a branched flow of ultrapure water as the main delivery liquid to flow from the pump space 1 successively through the firstblocking flow passage 6, thedischarge section 5, and thedischarge passage 5 c, preventing a liquid containing fine particles (a second blocking flow) from entering from the bearing assembly B and the mechanical seal assembly S into the pump space 1. - The pump device also has a supply source T of an inactive liquid (water), a metering pump P, a second blocking
flow supply port 7 that is open at the inner circumferential surface of therotational shaft casing 4 between the bearing assembly B and the mechanical seal assembly S, and a secondblocking flow passage 8 which is defined as a gap between the portion of therotational shaft 3 extending from the bearing assembly B to thedisk chamber 5 a and the inner circumferential surface of therotational shaft casing 4. The supply source T, the metering pump P, the second blockingflow supply port 7, and the secondblocking flow passage 8 make up a second blocking flow mechanism. If the pump space 1 is regarded as a front end, then the second blockingflow supply port 7 of the second blocking flow mechanism is positioned behind the blockingdisk 5 b disposed at a terminal end of the first blocking flow mechanism. An inactive liquid (water) supplied from the supply source T flows as a second blocking flow successively through the bearing assembly B, the secondblocking flow passage 8, thedischarge section 5, and thedischarge passage 5 c, preventing the first blocking flow (ultrapure water) coming from thedischarge section 5 of the first blocking flow mechanism from entering into the bearing assembly B. - As described above, the second blocking flow is combined with the first blocking flow in the
discharge section 5 of the first blocking flow mechanism, and flows out from thedischarge passage 5 c. In this embodiment, thedischarge section 5 is made up of thedisk chamber 5 a and theblocking disk 5 b, and thelabyrinth 5 d is provided in thedisk chamber 5 a, making it difficult for the blocking blows to combine with each other and allowing the blocking flows to flow as centrifugal flows due to the rotation of theblocking disk 5 b out from thedischarge passage 5 c. The first blocking flow is thus fully prevented from entering into the bearing assembly B. - The inactive liquid, which forms the second blocking flow, maybe ordinary tap water, and is supplied under a higher pressure and at a lower rate than the first blocking flow to the second
blocking flow passage 8 by the metering pump P. Since the second blocking flow flows under a high pressure and at a low rate, it is equalized in pressure to the first blocking flow in thedischarge section 5, and discharged out of the pump device through the flowrate regulating mechanisms discharge passage 5 c. The ratio of the flow rates of the first and second blocking flows, which are combined with each other, may be 1.5:1, or 50:1 or 100:1 in some cases. The direction of the blocking flows is determined by the flow rate of the first blocking flow as a main flow. The second blocking flow supplied to the pump device can maintain a large discharge rate. - If the pump device is inactivated for a long time, fine particles including metal ions produced from metal and ceramics of liquid-contacting regions brought into contact with the delivery liquid are entrained into the ultrapure water as the delivery liquid. Therefore, for achieving the ultrahigh purity of ultrapure water, whose metal ion concentration is required to be 1 PPT or less, immediately after the pump device has started to operate, it is necessary to clean the contaminated interior of the pump device with a large amount of flushing ultrapure water at the time the pump device starts to operate. However, the flushing process is responsible for an excessive increase in the running cost of the pump device.
- According to this embodiment, after the pump device has ceased to operate, the second blocking flow mechanism is immediately inactivated to stop the second blocking flow containing fine particles of metal and ceramics. At the same time, the main pump is operated again to circulate the first blocking flow at a rate, which is 1/10 or less of the ordinary rate, for thereby reliably preventing fine particles including eluted ions of metal and ceramics from entering into the pump space 1. Since the second blocking flow mechanism is filled with the second blocking flow, the first blocking flow does not enter into the bearing assembly B. The second blocking flow mechanism may be operated continuously or intermittently at a rate which is ½ of the ordinary rate. In this embodiment shown in
FIG. 1 , a lip seal L1 is provided as a check valve in the firstblocking flow passage 6, and a lip seal L2 is provided as a check valve in the secondblocking flow passage 8. - When a small amount of blocking flow is thus passed intermittently or continuously, ions of metal or the like, which are produced when the pump device is inactivated, are prevented from being spread into the entire pump device due to Brownian movement, thereby keeping a highly pure environment in the pump device.
-
FIG. 2 shows a pump device according to another embodiment of the present invention. The pump device shown inFIG. 2 is different from the pump device shown inFIG. 1 in that the bearing assembly B is dispensed with, and the rotary ring S2 of the mechanical seal assembly S is positioned closer to theimpeller 2, with the second blockingflow support port 7 being open in therotational shaft casing 4 between theblocking disk 5 b and the fixed ring S1 of the mechanical seal assembly S. - According to the present invention, with the above-described arrangement and operation, fine particles produced in the rotary sliding regions of the rotary pump are efficiently discharged at a low cost, the main delivery liquid is effectively prevented from entering into the rotary sliding regions, and fine particles, such as metal ions or the like, are prevented from being produced due to contact between the main delivery liquid, such as ultrapure water or the like, and the rotary sliding regions of the pump device.
- The present invention has been described above as having an outside-type mechanical seal having a fixed ring disposed in a pump chamber and a rotary ring and a spring disposed outside of the pump chamber. However, the present invention is also applicable to an inside-type mechanical seal mechanism having a rotary ring and a spring disposed in a pump chamber.
- The present invention is also applicable to a grand packing mechanism or a lip seal mechanism which is a rotary sliding seal mechanism other than the mechanical seal.
- As described above, a pump device according to the present invention for transporting ultrapure water or the like has a pump space, an impeller rotatable in the pump space, a rotational shaft interconnecting a rotational drive source and the impeller, and a rotational shaft casing having a bearing assembly and a seal assembly. The pump device has regions brought into contact with a main delivery liquid and treated for erosion resistance by a lining of tetrafluororesin or the like. The pump device also has a first blocking flow mechanism for preventing worn fine particles produced from rotary sliding components, such as the bearing assembly and the seal assembly, brought into contact with a second blocking flow, from being entrained into the delivery liquid, and a second blocking flow mechanism for preventing a main delivery liquid from entering from the pump space into regions, not treated for erosion resistance, of the rotary sliding components.
- The first blocking flow mechanism comprises a first blocking flow passage defined by the rotational shaft and an inner circumferential surface of the rotational shaft casing, a discharge section disposed in the rotational shaft casing closely to the impeller, for discharging a first blocking flow introduced as the main delivery liquid from the pump space into the rotational shaft casing, from the first blocking flow passage, and a discharge passage communicated with the discharge section.
- The second blocking flow mechanism comprises a supply source for supplying a inactive liquid, having a lubricity, as the second blocking flow, a second blocking flow passage for delivering the second blocking flow into the rotational shaft casing having the bearing assembly and the seal assembly positioned therein, the second blocking flow passage being defined by the rotational shaft and the inner circumferential surface of the rotational shaft casing, a second blocking flow supply port defined in the rotational shaft casing between an end of the rotational shaft closely to the rotary sliding components and the discharge passage, for combining the second blocking flow through the second blocking flow passage with the first blocking flow and discharging the second blocking flow from the discharge passage of the first blocking flow mechanism, and a supply passage disposed between the supply source and the second blocking flow supply port.
- In the above pump device, the discharge section of the first blocking flow mechanism comprises a blocking disk mounted on the rotational shaft in an area where the opposite flows meet each other, and a disk chamber defined in the rotational shaft casing and housing the blocking disk therein.
- A labyrinth is preferably provided in the disk chamber for preventing the first blocking flow and the second blocking flow from flowing into the second blocking flow passage and the first blocking flow passage, respectively.
- The regions not treated for erosion resistance in the rotational shaft casing is preferably filled at all times with the second blocking flow of the inactive liquid flowing in from the second blocking flow supply port, for isolation from the main delivery liquid having a strong chemical attack tendency which is introduced from the first blocking flow passage.
Claims (7)
1. A pump device comprising:
an impeller rotatable in a pump space;
a rotational shaft interconnecting a rotational drive source and said impeller;
a rotational shaft casing having a bearing assembly and/or a seal assembly;
a first blocking flow mechanism, having a discharge section for discharging a portion of a main delivery liquid introduced from said pump space as a first blocking flow, for preventing a second blocking flow containing fine particles produced by said bearing assembly and/or said seal assembly from being entrained into the main delivery liquid; and
a second blocking flow mechanism for combining said second blocking flow with said first blocking flow and discharging said second blocking flow from said discharge section while preventing said first blocking flow from being introduced.
2. A pump device according to claim 1 , wherein said first blocking flow mechanism has a first blocking flow passage defined between said rotational shaft and an inner circumferential surface of said rotational shaft casing, and said second blocking flow mechanism has a second blocking flow passage defined between said rotational shaft and an inner circumferential surface of said rotational shaft casing, said first blocking flow passage and said second blocking flow passage being disposed in respective positioned on both sides of said discharge section, said second blocking flow passage being supplied with an inactive liquid as said second blocking flow from a second blocking flow supply port which is open into said second blocking flow passage.
3. A pump device according to claim 1 , wherein said discharge section comprises a blocking disk mounted on said rotational shaft and a disk chamber defined in said rotational shaft casing and housing said blocking disk therein.
4. A pump device according to claim 3 , wherein a labyrinth is provided in said disk chamber between an inner circumferential surface of said disk chamber and said blocking disk.
5. A pump device according to claim 2 , wherein said second blocking flow has a higher liquid pressure than said first blocking flow at said second blocking flow supply port.
6. A pump device according to claim 2 , wherein said second blocking flow passage is filled at all times with the inactive liquid supplied from said second blocking flow supply port.
7. A pump device according to claim 1 , wherein said first blocking flow is discharged from said discharge section at a rate higher than said second blocking flow, the rate of said second blocking flow being at least 1.5 when the rate of said first blocking flow is 1.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/069,983 US20060198743A1 (en) | 2005-03-03 | 2005-03-03 | Pump device |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/069,983 US20060198743A1 (en) | 2005-03-03 | 2005-03-03 | Pump device |
Publications (1)
Publication Number | Publication Date |
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US20060198743A1 true US20060198743A1 (en) | 2006-09-07 |
Family
ID=36944281
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US11/069,983 Abandoned US20060198743A1 (en) | 2005-03-03 | 2005-03-03 | Pump device |
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US (1) | US20060198743A1 (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102013200659A1 (en) * | 2013-01-17 | 2014-07-17 | Bosch Mahle Turbo Systems Gmbh & Co. Kg | Exhaust gas turbocharger has shaft arranged in bearing housing, and compressor wheel drive-connected with shaft, where groove extends between inner side of shoulder facing radial gap and outer side of shoulder turned away from radial gap |
DE102014224283A1 (en) * | 2014-11-27 | 2016-06-02 | Robert Bosch Gmbh | Compressor with a sealing channel |
DE102014224285A1 (en) * | 2014-11-27 | 2016-06-02 | Robert Bosch Gmbh | Compressor with a sealing channel |
US20180216625A1 (en) * | 2015-08-06 | 2018-08-02 | Ebara Corporation | Shaft seal device and vertical pump with this shaft seal device |
US11448228B2 (en) * | 2018-02-05 | 2022-09-20 | Bestway Inflatables & Material Corp. | Pumps with a waterproof structure |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3213798A (en) * | 1964-03-16 | 1965-10-26 | Ingersoll Rand Co | Sealing and cooling device for a pump shaft |
US5865597A (en) * | 1995-03-31 | 1999-02-02 | Aisin Seiki Kabushiki Kaisha | Liquid pump for preventing contact between the sealing structure and pressurized liquid |
-
2005
- 2005-03-03 US US11/069,983 patent/US20060198743A1/en not_active Abandoned
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3213798A (en) * | 1964-03-16 | 1965-10-26 | Ingersoll Rand Co | Sealing and cooling device for a pump shaft |
US5865597A (en) * | 1995-03-31 | 1999-02-02 | Aisin Seiki Kabushiki Kaisha | Liquid pump for preventing contact between the sealing structure and pressurized liquid |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102013200659A1 (en) * | 2013-01-17 | 2014-07-17 | Bosch Mahle Turbo Systems Gmbh & Co. Kg | Exhaust gas turbocharger has shaft arranged in bearing housing, and compressor wheel drive-connected with shaft, where groove extends between inner side of shoulder facing radial gap and outer side of shoulder turned away from radial gap |
DE102014224283A1 (en) * | 2014-11-27 | 2016-06-02 | Robert Bosch Gmbh | Compressor with a sealing channel |
DE102014224285A1 (en) * | 2014-11-27 | 2016-06-02 | Robert Bosch Gmbh | Compressor with a sealing channel |
US10801513B2 (en) | 2014-11-27 | 2020-10-13 | Robert Bosch Gmbh | Compressor having a sealing channel |
US20180216625A1 (en) * | 2015-08-06 | 2018-08-02 | Ebara Corporation | Shaft seal device and vertical pump with this shaft seal device |
US10655632B2 (en) * | 2015-08-06 | 2020-05-19 | Ebara Corporation | Shaft seal device and vertical pump with this shaft seal device |
US11448228B2 (en) * | 2018-02-05 | 2022-09-20 | Bestway Inflatables & Material Corp. | Pumps with a waterproof structure |
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Owner name: EBARA CORPORATION, JAPAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:TAGA, JUN;REEL/FRAME:016701/0332 Effective date: 20050408 |
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