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EP0541929A1 - Système de pompage de gaz avec dispositif d'élimination de liquide - Google Patents

Système de pompage de gaz avec dispositif d'élimination de liquide Download PDF

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Publication number
EP0541929A1
EP0541929A1 EP92115781A EP92115781A EP0541929A1 EP 0541929 A1 EP0541929 A1 EP 0541929A1 EP 92115781 A EP92115781 A EP 92115781A EP 92115781 A EP92115781 A EP 92115781A EP 0541929 A1 EP0541929 A1 EP 0541929A1
Authority
EP
European Patent Office
Prior art keywords
gas flow
pump
pumping system
products
liquid
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.)
Withdrawn
Application number
EP92115781A
Other languages
German (de)
English (en)
Inventor
Yury Zlobinsky
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Thermo Savant Inc
Original Assignee
Savant Instruments Inc
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Savant Instruments Inc filed Critical Savant Instruments Inc
Publication of EP0541929A1 publication Critical patent/EP0541929A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C28/00—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids
    • F04C28/28—Safety arrangements; Monitoring
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B37/00—Pumps having pertinent characteristics not provided for in, or of interest apart from, groups F04B25/00 - F04B35/00
    • F04B37/10—Pumps having pertinent characteristics not provided for in, or of interest apart from, groups F04B25/00 - F04B35/00 for special use
    • F04B37/18—Pumps having pertinent characteristics not provided for in, or of interest apart from, groups F04B25/00 - F04B35/00 for special use for specific elastic fluids
    • F04B37/20—Pumps having pertinent characteristics not provided for in, or of interest apart from, groups F04B25/00 - F04B35/00 for special use for specific elastic fluids for wet gases, e.g. wet air
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B5/00—Drying solid materials or objects by processes not involving the application of heat
    • F26B5/04—Drying solid materials or objects by processes not involving the application of heat by evaporation or sublimation of moisture under reduced pressure, e.g. in a vacuum
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2270/00—Control; Monitoring or safety arrangements
    • F04C2270/70—Safety, emergency conditions or requirements
    • F04C2270/72—Safety, emergency conditions or requirements preventing reverse rotation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
    • F05B2270/00—Control
    • F05B2270/10—Purpose of the control system
    • F05B2270/109—Purpose of the control system to prolong engine life
    • F05B2270/1097—Purpose of the control system to prolong engine life by preventing reverse rotation

Definitions

  • the present invention relates to pumping systems and, more particularly, to gas pumping systems in which liquid condensation due to compression is prevented from entering a pump unit and causing pump damage and/or system malfunction.
  • Pumps used for handling a gas flow or transfer include, among others, diaphragm types, bellows types, vane types and in some applications, piston types.
  • a type selected for a given use purpose can depend on a number of factors such as nature of the product to be handled, function of pressurizing or evacuating a space etc.
  • Cold traps require refrigeration, are generally provided as bell jars, and do not always succeed in condensing certain organics from a gas stream since such may require considerably lower condensing temperature than the cold trap can reach.
  • Another object is to provide a gas pumping system which includes evaporator sections therein located relative to system pumping stages so as to evaporate any liquid in the system to vapor before such liquid could enter into and damage a pump.
  • a further object is to provide a gas pumping system with liquid eliminating evaporator sections that conveniently are embodied in conduits inletting to and outletting from pump units.
  • a still further object is to provide a gas products flow pumping system with liquid presence elimination capacity so that overall system operation is enhanced and made more effective to its designed purpose.
  • a plural pumping stage system for pumping a gas flow of products inclusive of aqueous and/or organic solvent fluids, the system being provided with evaporators at locations before and/or after pump stages, or at an interstage location to evaporate any condensed liquid presence back into the gas flow thereby to prevent damage to pump units and other components of the system, the evaporators being provided as heated section lengths of the conduits through which the gas flow passes, or as traps inserted in these conduits and in which any liquid presence in the gas flow is trapped and collected with any collection being heated with a trap heater to vaporize it back into the gas flow so ultimately all products are delivered in gas form to an end point location.
  • a pumping system for removing products inclusive of aqueous and/or organic solvent fluids as a gas flow from a space and delivering said products to a products end point location.
  • the system includes a plurality of pump units with these pump units being staged such that products gas flow from the space passes serially through successive stages from a first to a last of the pump units through conduits interconnecting the successive ones of the pump units.
  • An evaporator is provided in at least one a first of such interconnecting conduits and operates to vaporize any liquid form fluid present in the gas products passing through such first interconnecting conduit. This vaporization converts the liquid form to gaseous form so that all gas products entering the succeeding stage pump unit are essentially free of liquid.
  • the evaporator is positioned below an outlet from and in inlet to the pump units the first interconnecting conduit connects.
  • the evaporator can be a heated length section of the interconnecting conduit, heat being provided thereto by a heater encircling the length section. It also can be a trap interposed in the interconnecting conduit and in which liquid can be trapped and collected with collected liquid being heated and vaporized by heat supplied from a heater embodied with the trap.
  • the invention provides a pumping system for removing products inclusive of aqueous and/ or organic solvent fluids as a gas flow from a space and delivering said products to a products end point location.
  • the system includes a plurality of separate pump units with each pump unit having an inlet and an outlet, the inlet of at least one pump unit having a communicative course connection with the space and there being a communicative course connection of the end point location with one of the pump outlets.
  • An evaporator section is provided in both the communicative course connecting the inlet of the one pump unit and the space, and the communicative course connecting the end point location and the said one pump inlet.
  • evaporator sections operate to convert any liquid as may be present in the products gas flow passing therethrough to gaseous state, with the evaporators being located at an elevation below any communicative course connection to said space, any pump inlet and outlet, and said end point location.
  • the present invention provides a pumping system particularly intended for handling of gas flow such as is involved, e.g., in evacuating a space and in the course of which condensable aqueous or less volatile organic solvents are drawn therefrom, which solvents if condensed to liquid state could cause serious damage to pump units in the system.
  • Pump types that could be involved include diaphragm, bellows, vane and piston, and the system generally would involve plural stages, e.g., three serial stages employed to evacuated a space to very low pressure of say, 2 Torr.
  • the invention is especially suited for use in large capacity centrifugal dryers such as a SPEEDVAC as manufactured by SAVANT Instruments, Inc. wherein biological samples are dried and copious amounts of solvent principally water are removed from specimens during the drying operation.
  • large capacity centrifugal dryers such as a SPEEDVAC as manufactured by SAVANT Instruments, Inc. wherein biological samples are dried and copious amounts of solvent principally water are removed from specimens during the drying operation.
  • evaporator sections or traps are used at locations intervening a space wherein solvent is present and a first encountered pump stage, intermediate pumping stages, and after a last pump stage. At locations up to a last stage pump, the evaporator sections serve to remove liquid form of solvent from gas products flow so that same is not present within a pump unit where it could damage the pump unit working components since many pump types designed for gas handling service cannot withstand the abuse liquid can wreck therein.
  • An evaporator section or trap after a last pumping stage can be used to eliminate liquid presence in a system discharges line and the system back pressure it can produce. This is advantageous in regard to a plural stage vacuum pump system designed to evacuate a space to near complete vacuum condition since system back-pressure can impede achieving intended and needed space vacuum condition.
  • FIG. 1 depicts the principles involved with the invention.
  • a SPEEDVAC vacuum, centrifugal dryer 10 includes a rotor 12 on which is carried a number of specimen holders 14 containing, e.g., biological specimens which are to be dried, i.e., have solvent therein separated from the specimen composition.
  • the rotor rotates at high speed, heat may be applied to the space 18 within the dryer enclosure, and that space is connected via line 20 to a vacuum pump unit 22, that depicted being a single-stage diaphragm pump, but it being understood that a single stage is here shown only for descriptive purpose as the invention is intended for use primarily in plural-stage and especially three or more stage systems.
  • a trap 24 located a distance below the space 18 and the inlet to pump unit 22.
  • the trap unit is used to trap and retain any liquid solvent as is drawn from the specimen so that outlet flow from the trap and entering the pump unit is essentially gas products devoid of any liquid solvent presence that could damage the inner vitals of the pump structure.
  • Condensable forms of solvent that are retained in the trap are evaporated therein since a e.g., electrically operated heater 26 supplies heat to the trap to vaporize same and it in such vapor state, enters the gas products stream going to the pump unit.
  • the gas products stream in the pump is pressurized to a certain degree and is passed out of the pump unit and into another or post pumping trap 30, this trap functioning like trap 24 to trap and collect condensables in the trap rather than allowing for possibility that condensing could occur in discharge line 32 wherein it represents a back-pressure producing presence.
  • An impingement plate 34 can be provided inside the trap to facilitate effecting liquid separation from the gas flow, this being the same device as the baffle plate described in the above noted patent 5,025,571.
  • a heater 36 is employed to vaporize collected liquid solvent so that the solvent removed from the specimen, ultimately discharges to a solvent end point location via line 32.
  • the discharge to an end point location can be made at various locations, the trap 30 of course, being located below the pump outlet.
  • the lines connecting same to these are self draining to collection spaces whence that are evaporated to vapor form so no liquid solvent enters a system component or the environment.
  • Figure 2 shows a plural (at least three) stage pumping system embodying the present invention.
  • the system 40 includes respective first, second and third stage pump units 42-1, 42-2, and 42-3 which are arranged in serial succession so that discharge from stage one enters the next stage and so on until the discharge from the last stage is to the end point location.
  • Pump unit 42-1 takes suction from a space (not shown) which is being evacuated through line 46.
  • System 40 also includes a number of traps 44-1, 44-2, 44-3, and 44-4. These traps, which each has an associated heater 45 and temperature controller 47, serve the purpose described in Figure 1 and include inter-stage traps 44-2 and 44-3.
  • the invention mandates that there be in a plural, serial arranged pumping stage, a trap at least in the interstage between the first and second stages of pumping since this location is where greatest possibility of solvents condensables condensing exists.
  • FIG. 3 A system using plural pump units but not staged in succession but rather, the pump units being arrayed as single stage configuration, is shown in Figure 3.
  • This system 50 includes three pump units 52 each having direct connection to a space to be evacuated, such connection being to a common manifold 53 which in turn is connected to an outlet side 54 of a trap 56, the inlet to the trap being connected by line 58 to the space (not shown).
  • a manifold 60 connects each pump unit outlet to the inlet of a post-pumping trap 62, the trap outlet via line 64 being to a gas end point location.
  • Figure 5 shows a system 70 arranged like the Figure 2 system 40 but provided with a single common heater unit 72 having a single controller 74 serving in place of the individual such units used with the Figure 2 traps.
  • heater 72 is in good intimate thermally conductive contact with the trap structures to assure heat input to the trap interiors to effect evaporation of any liquid solvent collected therein.
  • Liquid solvent elimination need not be practiced only with trap units as shown in Figures 1-3 and 5. It also can be handled by using evaporator sections in various of the conduits in the pumping system.
  • An example of such embodiment is shown in the Figure 4 system 80.
  • System 80 has plural (two) pumps units 82, 84, connection to the space being evacuated being by conduit 86 connecting the space and the inlet of pump 82.
  • the outlet of pump 84 is via conduit 88 connected to the gas products end point location.
  • An interstage conduit 90 connects the two pump stages.
  • a section length of conduit at locations where liquid solvent could exist are encircled by heaters 92 each in good close intimate contact with the encircled conduit length section structure.
  • the heaters provide sufficient heat to vaporize any liquid state solvent as may exist in the gas flow through the length section so that by the time the gas flow passes beyond that length section, the liquid solvent renters the gas flow as a gas component too and flows onwardly in that state thereby eliminating any source cause for pump damage and/or back pressure in the system discharge line.
  • FIG. 6 shows the construction of the heaters 92.
  • the heater can include a case of inner and outer sheath members 93, 94 of ceramic or other material in between which are sandwich resistance heating elements 95, the sheath being in close conforming contact with the exterior of a conduit length section 98.
  • solvents as used herein is intended to cover a range of the liquids that can be found in specimen compositions, these including water and organic solvents. Further, the organic solvents would include those termed by one of ordinary skill in the art as being less and more volatile forms of solvents.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Molecular Biology (AREA)
  • Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
  • Control Of Non-Positive-Displacement Pumps (AREA)
  • Compressors, Vaccum Pumps And Other Relevant Systems (AREA)
  • Drying Of Solid Materials (AREA)
EP92115781A 1991-11-12 1992-09-16 Système de pompage de gaz avec dispositif d'élimination de liquide Withdrawn EP0541929A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US79077491A 1991-11-12 1991-11-12
US790774 1991-11-12

Publications (1)

Publication Number Publication Date
EP0541929A1 true EP0541929A1 (fr) 1993-05-19

Family

ID=25151709

Family Applications (1)

Application Number Title Priority Date Filing Date
EP92115781A Withdrawn EP0541929A1 (fr) 1991-11-12 1992-09-16 Système de pompage de gaz avec dispositif d'élimination de liquide

Country Status (2)

Country Link
EP (1) EP0541929A1 (fr)
JP (1) JPH06159284A (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3327286A4 (fr) * 2015-07-23 2019-03-13 Edwards Japan Limited Système de ventilation

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115434902B (zh) * 2022-11-07 2022-12-30 中国空气动力研究与发展中心超高速空气动力研究所 一种大流量高真空抽气系统的设计方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3630051A (en) * 1970-02-19 1971-12-28 Graham Mfg Co Inc Cold trap ice-removal means for vacuum drying systems
US5025571A (en) * 1990-04-25 1991-06-25 Savant Instruments, Inc. Vacuum pump with heated vapor pre-trap
EP0448750A1 (fr) * 1990-03-27 1991-10-02 Leybold Aktiengesellschaft Pompe à vide multiétagée avec compression à sec et procédé pour sa mise en oeuvre

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3630051A (en) * 1970-02-19 1971-12-28 Graham Mfg Co Inc Cold trap ice-removal means for vacuum drying systems
EP0448750A1 (fr) * 1990-03-27 1991-10-02 Leybold Aktiengesellschaft Pompe à vide multiétagée avec compression à sec et procédé pour sa mise en oeuvre
US5025571A (en) * 1990-04-25 1991-06-25 Savant Instruments, Inc. Vacuum pump with heated vapor pre-trap

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3327286A4 (fr) * 2015-07-23 2019-03-13 Edwards Japan Limited Système de ventilation

Also Published As

Publication number Publication date
JPH06159284A (ja) 1994-06-07

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