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
  • F04C15/00—Component parts, details or accessories of machines, pumps or pumping installations, not provided for in groups F04C2/00 - F04C14/00
  • F04C15/0057—Driving elements, brakes, couplings, transmission specially adapted for machines or pumps
  • F04C15/0076—Fixing rotors on shafts, e.g. by clamping together hub and shaft
• • 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
  • F04C13/00—Adaptations of machines or pumps for special use, e.g. for extremely high pressures
• • 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
  • F04C15/00—Component parts, details or accessories of machines, pumps or pumping installations, not provided for in groups F04C2/00 - F04C14/00
• • 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
  • F04C15/00—Component parts, details or accessories of machines, pumps or pumping installations, not provided for in groups F04C2/00 - F04C14/00
  • F04C15/0003—Sealing arrangements in rotary-piston machines or pumps
  • F04C15/0034—Sealing arrangements in rotary-piston machines or pumps for other than the working fluid, i.e. the sealing arrangements are not between working chambers of the machine
  • F04C15/0038—Shaft sealings specially adapted for rotary-piston machines or pumps
• • 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
  • F04C2220/00—Application
  • F04C2220/24—Application for metering throughflow

Definitions

• the present invention relates to a dosing pump for liquid products, as described in the preamble of claim 1.
• a gear pump of the type considered here comprises at least one driving gear and one driven gear, said gears each being carried by a shaft mounted on bearings arranged in the body of the pump. These bearings create parasitic spaces that are difficult to rinse and capable of retaining degraded, crystallized or hardened pumping product.
• One way to avoid these parasitic spaces is to have seals on each bearing, i.e. at least four seals per pump. These seals are expensive, generally require maintenance, and are always susceptible to leakage.
• Document JP-04041984 describes a gear pump in which the two gears are guided by the outer peripheral surface of the friction-sliding teeth on an inner peripheral surface of the pump chamber. If the problems mentioned above are partially eliminated by the elimination of the support shafts of the gears, the driving gear of this device is rotated by a shaft which is rigidly fixed to it. This has the drawback in particular of imposing the lateral position of the driving gear, which requires an enlargement of the pump chamber, hence additional lateral parasitic spaces difficult to rinse.
• a first object of the invention is therefore to propose a metering pump for liquid products improved with respect to known metering pumps.
• Yet another object is to provide a metering pump capable of metering a volume of liquid precisely.
• FIG. 1 represents a side view according to a first section of a metering pump for liquid products according to the invention
• FIG. 2 represents the same pump according to a section in a plane perpendicular to the section plane of the previous figure
• Figure 3 shows schematically the components of a metering pump.
• FIG. 1 shows that the body 1 of the pump comprises a bottom plate 10, an intermediate plate 11 and a front plate 12, these three plates having here an essentially quadrangular external shape of similar dimensions and being superimposed as seen on the Fig. Fixing means, shown diagrammatically at 13, hold these three plates together. A seal, not shown in the figure, seals the contacting faces of these three plates.
• the intermediate plate 11 seen in elevation in FIG. 2, consists essentially of a plate, quadrangular according to this embodiment, comprising a chamber 110, composed of at least two lobes, capable of each receiving a gear 30, 31 of a set of gears 3.
• the chamber 110 passes completely through the intermediate plate 11.
• the intermediate plate 11 further comprises a channel d liquid inlet 111 opening into chamber 110 as well as a liquid outlet channel 112 leaving said chamber.
• the orifices of the two channels can each be arranged on a side wall of the intermediate plate 11, as shown here, or else the channels 111 and / or 112 can extend into one or the other of the bottom plates 10 or before 12, their orifices being arranged on an outer face of these plates.
• the pump also comprises a set of gears 3 comprising a driving gear 30 and at least one driven gear 31 as well as drive means 4 and sealing means 5.
• the drive means 4 comprises a motorized means, not shown in this figure, terminated by a drive shaft 40 passing through a bearing 120 arranged in the front plate 12.
• the bearing 120 can be a plain bearing as shown here or a rolling bearing.
• the end 41 of the shaft 40 is formed so as to be introduced into a housing 300 of the gear 30, of corresponding shape, so as to be able to drive said gear in rotation.
• the end 41 and the housing 300 both have a hexagon shape, but any other shape allowing a rotation drive could be suitable.
• the gears 30 and 31 are not supported by any shaft, being only guided in rotation by the outer peripheral surface of the teeth in sliding contact on the inner periphery of the lobes of the chamber 110.
• the lubrication of the moving surfaces relative between them is ensured by the pumping product.
• the shaft 40 connected in a non-rigid manner to the driving gear 30 by its end 41 is only used for driving said gear, without having any support or guiding function.
• the shaft 40, respectively its end 41 can therefore only transmit a torque to the driving gear 30, to the exclusion of any other force in any direction.
• the gears 30 and 31 no longer being guided laterally by a shaft, they can be positioned laterally under the effect of the pressure of the pumping product acting on their lateral faces.
• the seal 5 may consist in a known manner of stuffings, lip seals or, as shown here, of a mechanical seal.
• the mechanical seal has the advantage of offering the lowest rotational friction force.
• a mechanical seal will be chosen, the latter comprising a sealing ring 50 mounted freely around the shaft 40, capable of moving. axially in a housing 121 arranged in the bearing 120, being pressed against the front face of the gear 30 by an elastic means, for example a spring 51 in order to mechanically seal between the chamber 110 and the shaft 40.
• An O-ring seal 52 forms a static sealing barrier on the rear of the sealing ring 50. Means not shown in the figure make it possible to prevent the rotation of the sealing ring.
• the construction of the packing 5 as described here makes it possible to postpone the sealing barrier as close as possible to the end 41 of the shaft 40, relative to the known constructions, thus contributing substantially to the reduction of the hollow spaces that need to be rinsed between two pumping products.
• the gear 30 was positioned laterally by the balance of pressures exerted on its two lateral faces. Since the surface of the side face of the gear 30 connected as described to the shaft 40 is less than the opposite side face, the gear 30 would tend to be pressed against the internal face of the front plate 12.
• the means elastic bands 51 will therefore be dimensioned so as to exert an axial force capable of compensating for the difference in opposite forces exerted on the two opposite lateral faces of the gear 30.
• the seal 5 described above is supplemented by a supply 53 of a barrier liquid coming from an external reservoir 54.
• the barrier liquid fills the portion of the housing 121 arranged on the side of the O-ring seal 52 opposite to that bathed by the pumping liquid, thus exerting a back pressure on this seal in order to improve its sealing.
• a leakage of barrier liquid in the direction of the chamber 110 or of the pumping liquid across the seal 52 causes a variation in the level of barrier liquid in the reservoir 54. By monitoring this level, it is therefore possible to detect a leak liquid in the packing, one way or the other.
• the presence of a barrier liquid in the hollow parts of the housing 121 also prevents condensation and crystallization of the pumping liquid in these hollow parts.
• the gear metering pump as described above is therefore optimized in order to substantially improve its rinsability by eliminating the hollow spaces to be rinsed between two different products to be pumped, which saves product as well as time. rinse.
• the simplified construction of the pump, reducing the number of its components and requiring only the presence of a single seal decreases the production cost as well as the risk of leaks and improves its reliability.
• the above pump can advantageously be used to dose a product to be pumped, the volume of product pumped being essentially proportional to the number of revolutions of the gears 30 or 31. It is therefore possible, by controlling this number of revolutions, to obtain a precision dosing pump.
• a pump is shown diagrammatically in FIG. 3.
• the other end of the shaft 40 is driven by a motor 41, preferably an electric motor, but which can also be a pneumatic, hydraulic motor or of any known type, capable of driving the shaft 40.
• a reduction gear or a gearbox 42 can be placed on the shaft 40 between the motor 41 and the pump. The speed of rotation of the gears 30 and 31 of the pump, respectively the volume of liquid pumped, is therefore equal or proportional to the number of rotations of rotation of the shaft 40 as well as of the motor 41.
• An encoder 43 capable of detecting this number of revolutions can therefore send a control signal to a control unit 44, for example an electronic unit containing or not a programmed microprocessor, capable of recording this signal and regulating the pumping process, for example cutting the power supply to the motor 41 when the desired amount of product has been pumped.
• the encoder can be placed at the end of the shaft on the motor 41, as shown diagrammatically by the encoder 43 in position A, on the shaft 40, before or after the possible reduction gear 42, as shown diagrammatically by the positrons B and C or in the pump itself, as shown schematically by position D.
• the encoder, 43 is of any known type, optical, inductive, capacitive or other, capable of reading the number of revolutions of the motor 41, of the shaft 40 or of a gear 30 or 31, depending on the position A, B, C or D where it is placed .
• the construction of the metering pump can be compact, the motor 41 being directly attached to the pump body 1 or else the construction can be more dispersed, the shaft 40 then consisting of a flexible drive shaft.
• a pump is advantageously associated with a robotic painting arm, for example for painting car bodies, the pump including its drive motor being housed in the mobile part of the robotic arm or else, so as to reduce the masses in motion as a minimum, the motor 41 can be housed in a base portion of the robotic arm while the pump body can be housed in the movable end of the arm, the two elements being connected by a flexible shaft 40.
• a dispersed construction, with a flexible or rigid drive shaft 40 also makes it possible to obtain an explosion-proof pump, the motor 41 capable of producing a spark that can be removed from the pump body 1 likely to be in an explosive atmosphere .
• the modular construction described therefore allows the use of such a dosing pump in numerous applications, painting, dosing of chemical, food, pharmaceutical or other products.
• the constituent elements of the pump body 1 as well as the gears 3 and the seal 5 are made of materials essentially compatible with the pumped products, these materials possibly being metals or alloys, for example stainless steel, synthetic materials or ceramics, these materials can be whether or not coated with a protective layer.
• the various components of the pump do not have to be made of the same material.
• a gear metering pump according to the invention.
• the pump has been described as comprising a driving gear and a driven gear; it could just as easily include a plurality of driven gears arranged on the periphery of a driving gear.
• the chamber of the pump body will therefore include the number of lobes required to each accommodate a gear.
• the pump body has been described as consisting of three assembled plates, this for reasons of ease of machining of the chamber 110 of the intermediate plate. It would also be possible for the intermediate plate 11 to be made in one piece with either the bottom plate 10 or the front plate 12.
• the pump body 1 has been described as being of quadrangular shape, it could in fact have any shape suitable for containing a pumping chamber as described.
• the metering pump has been described as comprising in particular an electric motor and an encoder. These two elements could be replaced by a stepping motor, the number of steps to be taken being determined by the volume of product to be pumped.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Rotary Pumps (AREA)
• Details And Applications Of Rotary Liquid Pumps (AREA)
• Reciprocating Pumps (AREA)
• Loading And Unloading Of Fuel Tanks Or Ships (AREA)
• Jet Pumps And Other Pumps (AREA)
• Cookers (AREA)

Applications Claiming Priority (1)

Publications (2)

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ID=4358072

Family Applications (1)

Country Status (6)

Cited By (2)

Families Citing this family (13)

Family Cites Families (16)

• 2000
  • 2000-05-08 US US10/258,632 patent/US6857860B1/en not_active Expired - Fee Related
  • 2000-05-08 AT AT00920319T patent/ATE263315T1/de not_active IP Right Cessation
  • 2000-05-08 EP EP00920319A patent/EP1280996B1/de not_active Expired - Lifetime
  • 2000-05-08 WO PCT/CH2000/000255 patent/WO2001086150A1/fr active IP Right Grant
  • 2000-05-08 AU AU2000240967A patent/AU2000240967A1/en not_active Abandoned
  • 2000-05-08 DE DE60009577T patent/DE60009577T2/de not_active Expired - Lifetime

Non-Patent Citations (1)

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