US5542835A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Leak detector for an injection moulding machine
Assignee: Teetotum Ltd
•
Filing: 1993-03-05
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Granted: 1996-08-06
•
Expires: 2013-03-05
Abstract
Abstract A leak detector for a plastics injection molding machine comprises a small diameter conduit (20) located adjacent to a potential leak site on or associated with the machine, through which a regulated supply of air is emitted. When the conduit outlet (26) is blocked with leaked molten plastics, a sensor (45) in the conduit instantly detects a change in air flow or back pressure and triggers an alarm (65), and optionally cuts off the machine automatically to avoid damage to machine components and with the object of reducing machine down time. Changes in incoming primary air supply pressure may be detected to provide a fail-safe system. Alternatively, air pressure in the conduit (20) may be below zero, i.e. a vacuum, so that air is sucked into the conduit at its outlet (26). Several potential leak sites may be monitored simulatneously from a single sensor arrangement.
Inventors
- 👤 Gerard P. Kennedy
- 👤 John P. M. Donnelly
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 08:20
CPC Classifications
G; G01; G01M; G01M3/00; G01M3/02; G01M3/04; B; B29; B29C; B29C45/00; B29C45/17; G01M3/26; B29C2045/1784; B29C2045/1795
Claims Analysis
Total Claims: 42
Claim 1
Independent Claim
102 words
A plastics injection moulding machine including an injection nozzle and a sprue bush, and having a leak detector for leaks of molten plastics comprising a conduit for supplying a flow of fluid to a conduit outlet located adjacent to the nozzle and the sprue bush, a source of fluid in communication with the conduit outlet, means capable of sensing changes in fluid pressure inside the conduit caused by the presence of leaked material blocking the conduit outlet and of producing an electronic output signal, and electronic indicating means responsive to the electronic output signal and capable of instantaneously indicating a leak condition.
Claim 2
Dependent Claim
102 words
A plastics injection moulding machine including an injection nozzle and a sprue bush, and having a leak detector for leaks of molten plastics comprising a conduit for supplying a flow of fluid to a conduit outlet located adjacent to the nozzle and the sprue bush, a source of fluid in communication with the conduit outlet, means capable of sensing changes in fluid pressure inside the conduit caused by the presence of leaked material blocking the conduit outlet and of producing an electronic output signal, and electronic indicating means responsive to the electronic output signal and capable of instantaneously indicating a leak condition.
Claim 3
Dependent Claim
13 words
A machine according to claim 1, wherein the source of fluid is air.
Claim 4
Dependent Claim
15 words
A machine according to claim 2, wherein air is supplied at a substantially constant pressure.
Claim 5
Dependent Claim
19 words
A machine according to claim 3, wherein air pressure at the conduit outlet is less than about 345 mb.
Claim 6
Dependent Claim
17 words
A machine according to claim 4, having a flow regulator upstream of the pressure change sensing means.
Claim 7
Dependent Claim
23 words
A machine according to claim 5, having a pressure regulator, upstream of the flow regulator, to limit the maximum pressure of supplied air.
Claim 8
Dependent Claim
24 words
A machine according to claim 5, having a pressure relief valve, downstream of the flow regulator, to limit the maximum pressure of supplied air.
Claim 9
Dependent Claim
18 words
A machine according to claim 1, wherein the conduit is located along the barrel of the injection nozzle.
Claim 10
Dependent Claim
18 words
A machine according to claim 1, wherein the conduit is located within the barrel of the injection nozzle.
Claim 11
Dependent Claim
18 words
A machine according to claim 1, wherein the conduit is located on a platen adjacent the sprue bush.
Claim 12
Dependent Claim
33 words
A machine according to claim 1, wherein the pressure change sensing means comprises a pressure sensor sensitive to changes of pressure within a range of from about 5 mb to about 690 mb.
Claim 13
Dependent Claim
38 words
A machine according to claim 1, wherein the electronic indicating means is a relay together with an audible alarm, operatively linked to the machine controls so as to interrupt the operation of the machine during a leak condition.
Claim 14
Dependent Claim
15 words
A machine according to claim 1, wherein the conduit outlet defines a detachable tip portion.
Claim 15
Dependent Claim
103 words
A plastics injection moulding machine including an injection nozzle and a sprue bush, and having a leak detector for leaks of molten plastics comprising a conduit for supplying intermittent pulses of fluid to a conduit outlet located adjacent to the nozzle and the sprue bush, a source of fluid in communication with the conduit outlet, means capable of sensing changes in fluid back pressure inside the conduit caused by the presence of leaked material blocking the conduit outlet and of producing an electronic output signal, and electronic indicating means responsive to the electronic output signal and capable of instantaneously indicating a leak condition.
Claim 16
Dependent Claim
103 words
A plastics injection moulding machine including an injection nozzle and a sprue bush, and having a leak detector for leaks of molten plastics comprising a conduit for supplying intermittent pulses of fluid to a conduit outlet located adjacent to the nozzle and the sprue bush, a source of fluid in communication with the conduit outlet, means capable of sensing changes in fluid back pressure inside the conduit caused by the presence of leaked material blocking the conduit outlet and of producing an electronic output signal, and electronic indicating means responsive to the electronic output signal and capable of instantaneously indicating a leak condition.
Claim 17
Dependent Claim
13 words
A machine according to claim 14, wherein the source of fluid is air.
Claim 18
Dependent Claim
16 words
A machine according to claim 15, wherein air is supplied as pulses about every 30 seconds.
Claim 19
Dependent Claim
18 words
A machine according to claim 14, wherein the conduit is located along the barrel of the injection nozzle.
Claim 20
Dependent Claim
18 words
A machine according to claim 14, wherein the conduit is located within the barrel of the injection nozzle.
Claim 21
Dependent Claim
18 words
A machine according to claim 14, wherein the conduit is located on a platen adjacent the sprue bush.
Claim 22
Dependent Claim
34 words
A machine according to claim 14, wherein the pressure change sensing means comprises a pressure sensor sensitive to changes of back pressure within a range of from about 5 mb to about 690 mb.
Claim 23
Dependent Claim
38 words
A machine according to claim 14, wherein the electronic indicating means is a relay together with an audible alarm, operatively linked to the machine controls so as to interrupt the operation of the machine during a leak condition.
Claim 24
Dependent Claim
15 words
A machine according to claim 14, wherein the conduit outlet defines a detachable tip portion.
Claim 25
Dependent Claim
103 words
A plastics injection moulding machine including an injection nozzle and a sprue bush, and having a leak detector for leaks of molten plastics comprising a conduit for applying a vacuum to a conduit outlet located adjacent to the nozzle and the sprue bush, a source of air in communication with the conduit outlet, means capable of sensing changes in less than atmospheric air pressure inside the conduit caused by the presence of leaked material blocking the conduit outlet and of producing an electronic output signal, and electronic indicating means responsive to the electronic output signal and capable of instantaneously indicating a leak condition.
Claim 26
Dependent Claim
103 words
A plastics injection moulding machine including an injection nozzle and a sprue bush, and having a leak detector for leaks of molten plastics comprising a conduit for applying a vacuum to a conduit outlet located adjacent to the nozzle and the sprue bush, a source of air in communication with the conduit outlet, means capable of sensing changes in less than atmospheric air pressure inside the conduit caused by the presence of leaked material blocking the conduit outlet and of producing an electronic output signal, and electronic indicating means responsive to the electronic output signal and capable of instantaneously indicating a leak condition.
Claim 27
Dependent Claim
18 words
A machine according to claim 23, wherein the conduit is located along the barrel of the injection nozzle.
Claim 28
Dependent Claim
18 words
A machine according to claim 23, wherein the conduit is located within the barrel of the injection nozzle.
Claim 29
Dependent Claim
18 words
A machine according to claim 23, wherein the conduit is located on a platen adjacent the sprue bush.
Claim 30
Dependent Claim
33 words
A machine according to claim 23, wherein the pressure change sensing means comprises a pressure sensor sensitive to changes of pressure within a range of from about 3.75 Torr to about 517 Torr.
Claim 31
Dependent Claim
38 words
A machine according to claim 23, wherein the electronic indicating means is a relay together with an audible alarm, operatively linked to the machine controls so as to interrupt the operation of the machine during a leak condition.
Claim 32
Dependent Claim
15 words
A machine according to claim 23, wherein the conduit outlet defines a detachable tip portion.
Claim 33
Dependent Claim
104 words
A plastics injection moulding machine including an injection nozzle and a sprue bush, and having a leak detector for leaks of molten plastics comprising a conduit for applying a pulsed vacuum to a conduit outlet located adjacent to the nozzle and the sprue bush, a source of air in communication with the conduit outlet, means capable of sensing changes in less than atmospheric air pressure inside the conduit caused by the presence of leaked material blocking the conduit outlet and of producing an electronic output signal, and electronic indicating means responsive to the electronic output signal and capable of instantaneously indicating a leak condition.
Claim 34
Dependent Claim
104 words
A plastics injection moulding machine including an injection nozzle and a sprue bush, and having a leak detector for leaks of molten plastics comprising a conduit for applying a pulsed vacuum to a conduit outlet located adjacent to the nozzle and the sprue bush, a source of air in communication with the conduit outlet, means capable of sensing changes in less than atmospheric air pressure inside the conduit caused by the presence of leaked material blocking the conduit outlet and of producing an electronic output signal, and electronic indicating means responsive to the electronic output signal and capable of instantaneously indicating a leak condition.
Claim 35
Dependent Claim
18 words
A machine according to claim 30, wherein the conduit is located along the barrel of the injection nozzle.
Claim 36
Dependent Claim
18 words
A machine according to claim 30, wherein the conduit is located within the barrel of the injection nozzle.
Claim 37
Dependent Claim
18 words
A machine according to claim 30, wherein the conduit is located on a platen adjacent the sprue bush.
Claim 38
Dependent Claim
33 words
A machine according to claim 30, wherein the pressure change sensing means comprises a pressure sensor sensitive to changes of pressure within a range of from about 3.75 Torr to about 517 Torr.
Claim 39
Dependent Claim
38 words
A machine according to claim 30, wherein the electronic indicating means is a relay together with an audible alarm, operatively linked to the machine controls so as to interrupt the operation of the machine during a leak condition.
Claim 40
Dependent Claim
15 words
A machine according to claim 30, wherein the conduit outlet defines a detachable tip portion.
Claim 41
Independent Claim
177 words
A system for detecting leaks of molten plastics at a plurality of potential leak sites in a plastics injection moulding machine which machine comprises a multi-gate hot runner arrangement comprising a manifold defining channels communicating with gates through which molten plastics is injected via a main injection nozzle and sprue bush into a two-part mould defining a mould cavity, the manifold also defining heater wiring ducts, in which the leak detection system comprises at least one conduit for supplying a flow of fluid to an outlet thereof located adjacent to a respective potential leak site in the system, a source of fluid in communication with each respective conduit outlet, means capable of sensing changes in fluid pressure inside each of the conduits caused by the presence of leaked molten plastics material blocking the respective conduit outlet and capable of producing an identifiable electronic output signal, and control circuit means for simultaneously monitoring said identifiable output signals so as to detect a leak at the different potential leak sites, and for indicating the location of any leak condition.
Claim 42
Independent Claim
177 words
A system for detecting leaks of molten plastics at a plurality of potential leak sites in a plastics injection moulding machine which machine comprises a multi-gate hot runner arrangement comprising a manifold defining channels communicating with gates through which molten plastics is injected via a main injection nozzle and sprue bush into a two-part mould defining a mould cavity, the manifold also defining heater wiring ducts, in which the leak detection system comprises at least one conduit for supplying a flow of fluid to an outlet thereof located adjacent to a respective potential leak site in the system, a source of fluid in communication with each respective conduit outlet, means capable of sensing changes in fluid pressure inside each of the conduits caused by the presence of leaked molten plastics material blocking the respective conduit outlet and capable of producing an identifiable electronic output signal, and control circuit means for simultaneously monitoring said identifiable output signals so as to detect a leak at the different potential leak sites, and for indicating the location of any leak condition.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-08-06 | 2000-02-05 | 2000-08-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-08-06 | 2004-02-05 | 2004-08-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-08-06 | 2008-02-05 | 2008-08-06 | $7700.00 | Window Closed / Lapsed |