Vacuum generating device and method for the operation thereof
First Claim
1. A method for determining an extent of air leakage in a vacuum generating device, having an ejector device, the ejector device having an inlet connected with an air supply conduit and whose suction side is connected with a suction channel, which is connected with a suction gripper, and which has a pressure detection installation for detecting the vacuum in the suction channel, wherein the vacuum in the suction channel is regulated in that the air supply of the inlet is turned off at a time t1 once the vacuum pressure has reached an upper switching value PSO and is switched on again at a time t2 once the vacuum pressure drops to a lower switching value PSU and remains on until a time t3 when the upper switching value PSO has been reached, and wherein a regulating time tR which has passed between a shutting off of the air supply at time t1 and either a subsequent restarting at time t2, or a renewed shutting off of the air supply at time t3, is detected and compared with at least one predetermined reference time value in order to generate an electrical diagnostic signal as a function of the result of the comparison, andwherein the regulating time is a measure of how quickly the vacuum in the suction channel decays and the electrical diagnostic signal is determinative of an extent of leakage in the vacuum generating device.
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Accused Products
Abstract
The invention relates to a vacuum generating device (1) and to a method suitable for the operation thereof. An ejector device (27) is connected with an inlet (29) thereof to an air supply conduit (32) that can be selectively closed or opened by an electronic control unit (14) in order to selectively turn off or turn on the ejector device (27). When the ejector device (27) is turned on, a vacuum is generated in a suction channel (35). The ejector device (27) is operated such that the vacuum fluctuates between an upper switching value and a lower switching value. By comparison to a reference time value, the operating period of the ejector device (27) is determined in order to generate a diagnosis signal that allows a conclusion of the leak that is present.
21 Citations
16 Claims
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1. A method for determining an extent of air leakage in a vacuum generating device, having an ejector device, the ejector device having an inlet connected with an air supply conduit and whose suction side is connected with a suction channel, which is connected with a suction gripper, and which has a pressure detection installation for detecting the vacuum in the suction channel, wherein the vacuum in the suction channel is regulated in that the air supply of the inlet is turned off at a time t1 once the vacuum pressure has reached an upper switching value PSO and is switched on again at a time t2 once the vacuum pressure drops to a lower switching value PSU and remains on until a time t3 when the upper switching value PSO has been reached, and wherein a regulating time tR which has passed between a shutting off of the air supply at time t1 and either a subsequent restarting at time t2, or a renewed shutting off of the air supply at time t3, is detected and compared with at least one predetermined reference time value in order to generate an electrical diagnostic signal as a function of the result of the comparison, and
wherein the regulating time is a measure of how quickly the vacuum in the suction channel decays and the electrical diagnostic signal is determinative of an extent of leakage in the vacuum generating device.
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7. A method for the operation of a vacuum generating device, having an ejector device, the ejector device having an inlet connected with an air supply conduit and whose suction side is connected with a suction channel, which is connected with a suction gripper, and which has a pressure detection installation for detecting the vacuum in the suction channel, wherein the vacuum in the suction channel is regulated in that the air supply of the inlet is turned off once the vacuum has reached an upper switching value and is switched on again once the vacuum drops to a lower switching value and remains on until the upper switching value has been reached, and wherein a regulating time which has passed between a shutting off of the air supply and either a subsequent restarting, or a renewed shutting off of the air supply, is detected and compared with at least one predetermined reference time value in order to generate an electrical diagnostic signal as a function of the result of the comparison, and
wherein the upper switching value and the lower switching value are fixed by a process, wherein (a) a first suction channel pressure with the suction gripper closed, and a second suction channel pressure with the suction gripper open or covered by a leaky object are determined, (b) a mean pressure value is calculated from the first and second suction channel pressure, (c) the mean pressure value itself, or with the addition of a safety pressure value, is determined to be the lower switching value, and (d) the first suction channel pressure itself, or minus a safety pressure value, is determined to be the upper switching value.
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8. A vacuum generating device, having an ejector device which has an inlet connected with an air supply conduit and has a suction opening, to which a suction channel is connected which is, or can be, connected with a suction gripper, furthermore with a pressure detection installation used for detecting the vacuum in the suction channel, and with an electronic regulating device for regulating the vacuum in the suction channel in such a way that the air supply to the inlet is switched off at a time t1 when the vacuum pressure being built up has reached an upper switching value PSO, and is again switched on at a time t2 once the vacuum pressure drops to a lower switching value PSU and remains on until a time t3 when the upper switching value PSO has been reached, wherein the regulating device has regulating time detection means, by means of which the regulating time tR passing between a switching off of the air supply at time t1 and either a subsequent restarting at time t2 or the renewed switching off of the air supply at time t3 can be detected, and wherein the regulating device furthermore has comparison means, by means of which the detected regulating time tR can be compared with at least one reference time value stored in a memory means, and wherein the regulating device has output means which, as a function of the result of the comparison made by the comparison means, outputs an electrical diagnostic signal, and
wherein the regulating time is a measure of how quickly the vacuum in the suction channel decays and the electrical diagnostic signal is determinative of an extent of leakage in the vacuum generating device.
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16. A method for determining an extent of air leakage in a vacuum generating device having an ejector device, the ejector device having an inlet connected with an air supply conduit and whose suction side is connected with a suction channel, which is connected with a suction gripper, and which has a pressure detection installation for detecting a vacuum in the suction channel, the method comprising:
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supplying air to the ejector device inlet at a time t0 to build a vacuum pressure in the suction channel; detecting the vacuum pressure in the suction channel; turning off the air supply to the ejector device inlet at a time t1 once the vacuum pressure detected in the suction channel has reached an upper switching value PSO; switching on the air supply to the ejector device inlet at a time t2 once the vacuum pressure detected in the suction channel drops to a lower switching value PSU, the air supply remaining switched on until the upper switching value PSO has again been reached at a time t3; shutting off the air supply to the ejector device inlet at the time t3 once the vacuum pressure detected in the suction channel has again reached an upper switching value PSO; measuring a regulating time tR passing between the turning off of the air supply to the ejector device inlet at the time t1 and either the subsequent switching on at the time t2 or subsequent shutting off of the air supply at the time t3, the regulating time tR being a measure of how quickly the vacuum in the suction channel decays; comparing the regulating time tR with at least one predetermined reference time value; generating an electrical diagnostic signal if the regulating time tR is less than the at least one predetermined reference time value, the electrical diagnostic signal being determinative of an extent of leakage in the vacuum generating device.
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Specification