EP0195618B1 - Metering pump - Google Patents

Metering pump Download PDF

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Publication number
EP0195618B1
EP0195618B1 EP86301871A EP86301871A EP0195618B1 EP 0195618 B1 EP0195618 B1 EP 0195618B1 EP 86301871 A EP86301871 A EP 86301871A EP 86301871 A EP86301871 A EP 86301871A EP 0195618 B1 EP0195618 B1 EP 0195618B1
Authority
EP
European Patent Office
Prior art keywords
pump
pistons
piston
outlet port
filling
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.)
Expired
Application number
EP86301871A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0195618A3 (en
EP0195618A2 (en
Inventor
Albert Henry Morland
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.)
CooperVision Optics Ltd
Original Assignee
CooperVision Optics Ltd
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 CooperVision Optics Ltd filed Critical CooperVision Optics Ltd
Priority to AT86301871T priority Critical patent/ATE47673T1/de
Publication of EP0195618A2 publication Critical patent/EP0195618A2/en
Publication of EP0195618A3 publication Critical patent/EP0195618A3/en
Application granted granted Critical
Publication of EP0195618B1 publication Critical patent/EP0195618B1/en
Expired legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
    • B01F35/71—Feed mechanisms
    • B01F35/714—Feed mechanisms for feeding predetermined amounts
    • B01F35/7141—Feed mechanisms for feeding predetermined amounts using measuring chambers moving between a loading and unloading position, e.g. reciprocating feed frames

Definitions

  • This invention relates to apparatus for filling contact lens moulds with a polymerisable liquid casting composition and includes a pump which is capable of delivering sequential doses of equal volume of the liquid.
  • Peristaltic pumps are also widely used since they have the advantage that no moving parts are in contact with the liquid to be pumped. When a batch has been completed the flexible tube which forms the body of the peristaltic pump can simply be discarded, thereby obviating the need to clean the pump.
  • these pumps have the disadvantage that they cannot pump effectively against a positive pressure and the flexible plastic tubing which is used to form the body of the pump tends to be permeable to many reactive or volatile liquids.
  • FR-A-2383607 describes apparatus for dispensing measured quantities of dough for making bread.
  • the apparatus includes a cylinder having an inlet hole which is attached to a hopper for the bread dough.
  • a pair of opposed pistons are received in the cylinder and are connected by piston rods to slides which are driven by a crank arm. Movement of the slides causes one piston to move outwardly to suck a measured quantity of dough into the cylinder and then the second piston to move towards the first and to eject the dough out of the cylinder.
  • the present application is concerned with a solution to the problem of filling contact lens moulds with a measured quantity of a polymerisable lens casting composition in an accurate and repeatable fashion.
  • This is achieved by connecting a pump adapted to deliver measured doses of a polymerisable casting composition to a mould filling nozzle and providing means for causing relatively movement of the filling nozzle and a mould so that the nozzle enters the mould in synchronism with the delivery of a measured dose of said casting composition by the pump.
  • accurate delivery is achieved without risk of loss of the composition by splashing.
  • apparatus for filling contact lens moulds with a polymerisable liquid casting composition which comprises:
  • the body of the pump consists of a solid block of metal, plastics material or glass, which is formed with a cylindrical longitudinal bore and additionally with longitudinally spaced cross-bores to provide the inlet and outlet ports.
  • the pistons may be cylindrical rods of diameter corresponding to the longitudinal bore in the body and may likewise be formed from a suitable metal, plastics or glass material. Dsir- ably, materials are selected which are resistant to corrosion by the liquids intended to be pumped and provide surfaces which can be readily cleaned. It has been found that polytetrafluoroethylene (PTFE) is an advantageous material for manufacturing components of the pump since it combines low sliding friction with relative inertness to many chemicals and solvents. An effective pump can be manufactured using a block of PTFE for the body of the pump and stainless steel rods for the pistons.
  • PTFE polytetrafluoroethylene
  • the body of the pump may be supported on a fixed base and the two pistons mounted on a movable carriage so that sliding movement of the carriage will cause the pistons to slide in the body.
  • Discharge of the liquid from the pump is conveniently achieved by interposing a pneumatic or hydraulic piston and cylinder device between one of the pistons and the carriage.
  • the volume of liquid which is to be pumped in each cycle can be controlled by limiting the outward movement of one of the pistons by a predetermined amount This can be done by providing a proximity switch which senses outward movement of the piston and cylinder device or the pump piston and operates a supply valve for the piston and cylinder device.
  • the apparatus in accordance with the invention is particularly suitable for delivering measured amounts of a monomer mixture to a contact lens casting mould.
  • a plurality of pumps may be formed as an assembly for this purpose.
  • the individual pump bodies may be supported on a common base and their respective pistons connected to a carriage which is movable relatively to the base so that the pumps simultaneously pump the same measured dose of monomer.
  • Figure 1 is a side elevation of a pump and operating mechanism in accordance with one embodiment of the invention.
  • Figure 2 is a plan view seen from above of the pump shown in Figure 1, and
  • Figure 3 shows the filling of lens moulds.
  • the pump comprises a generally rectangular block 1 formed from PTFE having a longitudinal cylindrical bore 2 within which is received a pair of opposed pistons 3 and 4 whose opposed faces when spaced apart provide a chamber 5.
  • the opposite ends of pistons 3 and 4 are received in mountings 6 and 7 respectively and the size of chamber 5 (which will determine the volume of liquid to be dispensed) can be adjusted by altering the amount by which the rod 3 or 4 projects from its respective mounting 6 or 7 or by adjustment of the working stroke of a ram 17 to which mounting 7 is connected.
  • Valve body 1 is rigidly supported on a plate 8 which is fixed to a base 91 by pillars 9.
  • Mountings 6 and 7, which carry pistons 3 and 4 are supported on a carriage 10 which is mounted for sliding movement on bars 11.
  • Movement of the carriage is effected by ram 12 which, for a precisely accurate movement, is preferably hydraulic.
  • Crossbores 13 and 14 are formed in body 1 and these provide the outlet and inlet ports respectively of the pump.
  • the inlet port 14 is fed by gravity from a reservoir 15 through a flexible tube 16, since a gravity feed minimises formation of bubbles which would reduce the accuracy of the dose.
  • Piston 4 can be moved independently of piston 3 by means of ram 17, which is also preferably hydraulic. Seals, such as O-ring seals, may be pressed into the block 1 at 18 and 19 to prevent seepage of liquid out of the pump between the longitudinal bore and the pistons 3 and 4.
  • the pump operates in the following manner.
  • the inlet stroke commences with the piston 3 in the position shown in Figure 1 and the face of piston 4 in contact with it.
  • Piston 4 moves in the right hand direction (as seen in Figure 1) under the influence of ram 17.
  • This causes liquid to be sucked into the pump via inlet 14.
  • Ram 17 continues to move to the right until the desired volume of liquid has been sucked into the pump.
  • the ram 17 is programmed to move outwardly by a predetermined amount so that a known volume of liquid has been sucked into the pump.
  • Ram 12 is then operated to move the carriage 10, and hence the pistons 3 and 4 in unison (i.e. without altering the relative separation of the opposed faces of pistons 3 and 4), in the direction indicated by arrow A in Figure 1.
  • ram 12 stops.
  • ram 17 operates to move piston 4 towards piston 3, thereby closing the gap between the opposed faces of the two pistons and forcing the entire volume of liquid in chamber 5 out of the pump through outlet 13.
  • Ram 12 then operates again in the reverse direction to return the pistons to their starting position while the pistons remain in contact. This cycle is repeated in a reciprocating fashion to deliver equal measured volumes of liquid sequentially through outlet 13.
  • the movement of rams 12 and 17 can be controlled by proximity switches (e.g. magnetic switches) mounted on the cylinders of the rams which sense the positions of the pistons of the rams and are connected to electro-magnetic valves which control the flow of hydraulic fluid to the rams 12 and 17.
  • cleaning the pump of the present invention is a simple matter since there are only two moving parts, namely the pistons 3 and 4, and no valves which need to be dismantled.
  • the apparatus is particularly useful for dispensing measured volumes of monomers into moulds for the manufacture of plastic contact lenses.
  • the outlet port 13 of the pump may be fitted, with a thin outlet tube 20 which terminates in a hollow needle 21 designed to enter the female mould cavity and deliver a measured volume of monomer into the base of the mould.
  • a suitable mechanism can be provided for advancing unfilled moulds in timed sequence to the outlet from the pump so that each female mould cavity is filled with the same volume of monomer and is then closed and polymerised.
  • a plurality of metering pumps are preferably assembled as a single filling apparatus. This is preferably achieved by mounting a plurality of pump bodies 31, 41, side-by-side on the support plate 8 as indicated in Figure 2.
  • the pistons of the pumps may be connected to the carriage 10 and ram 17 so that the pumps operate in synchronism.
  • up to about 10 to 12 pumps can readily be connected together to form a single filling apparatus.
  • the reservoir 15 is provided with an appropriate number of supply nozzles 216, 316, etc, for connection to supply tubes, similar to tube 16, for each of the pumps.
  • the outlet tubes from the pump outlet ports 20 are conducted to a mould filling station, where mould filling tubes are clustered in a circular array above a table for holding the female moulds.
  • a mould filling station where mould filling tubes are clustered in a circular array above a table for holding the female moulds.
  • Figure 3 shows schematically in which the table 25 is mounted on a slide so that empty mould halves can be moved beneath the array of filling tubes.
  • the array of filling tubes is raised and the filled moulds transferred to a mould closing station. It is advantageous for the filling tubes to be moved downwardly into the mould (or the mould to be moved upwardly towards the tube) so that its end is just above the bottom of the mould during filling. This avoids any splashing of droplets of monomer up the sides of the mould. Movement of the tube away from the. liquid in the mould after filling avoids variations in amount of monomer filled, due to a droplet of monomer adhering to the end of the filling tube.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Lubrication Of Internal Combustion Engines (AREA)
  • Eye Examination Apparatus (AREA)
  • Measuring Pulse, Heart Rate, Blood Pressure Or Blood Flow (AREA)
  • Reciprocating Pumps (AREA)
  • Casting Or Compression Moulding Of Plastics Or The Like (AREA)
  • Infusion, Injection, And Reservoir Apparatuses (AREA)
EP86301871A 1985-03-19 1986-03-14 Metering pump Expired EP0195618B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT86301871T ATE47673T1 (de) 1985-03-19 1986-03-14 Dosierpumpe.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB858507064A GB8507064D0 (en) 1985-03-19 1985-03-19 Metering pump
GB8507064 1985-03-19

Publications (3)

Publication Number Publication Date
EP0195618A2 EP0195618A2 (en) 1986-09-24
EP0195618A3 EP0195618A3 (en) 1986-11-12
EP0195618B1 true EP0195618B1 (en) 1989-11-02

Family

ID=10576229

Family Applications (1)

Application Number Title Priority Date Filing Date
EP86301871A Expired EP0195618B1 (en) 1985-03-19 1986-03-14 Metering pump

Country Status (5)

Country Link
EP (1) EP0195618B1 (ja)
JP (1) JPS61291780A (ja)
AT (1) ATE47673T1 (ja)
DE (1) DE3666669D1 (ja)
GB (2) GB8507064D0 (ja)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ES1021312Y (es) * 1992-05-19 1993-04-01 Caravaca Treves Milton David Dosificador de alginato para uso odontologico.
CN106523318B (zh) * 2016-10-31 2019-04-02 深圳市世椿智能装备股份有限公司 一种双向活塞泵及其控制方法

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1662969A (en) * 1926-10-13 1928-03-20 Gerace Giuseppe Batter-measuring machine
GB1317412A (en) * 1971-09-06 1973-05-16 Anchor Hocking Corp Mixing and metering apparatus
FR2383607A1 (fr) * 1977-03-18 1978-10-13 Laurent Raymond Dispositif a double piston pour diviser automatiquement la pate a pain
US4366918A (en) * 1979-04-20 1983-01-04 Naka Seiki Company Limited Variable ratio metering, mixing and dispensing apparatus
US4290700A (en) * 1979-11-08 1981-09-22 Mechanical Service Company Measuring apparatus for shot dispensers

Also Published As

Publication number Publication date
DE3666669D1 (en) 1989-12-07
GB8507064D0 (en) 1985-04-24
EP0195618A3 (en) 1986-11-12
GB2172666A (en) 1986-09-24
EP0195618A2 (en) 1986-09-24
ATE47673T1 (de) 1989-11-15
JPS61291780A (ja) 1986-12-22
GB8606325D0 (en) 1986-04-23

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