US 5,771,178 A · Fail-safe fluid transfer controller

Abstract

A fail-safe fluid transfer control apparatus has full redundancy in the response to various inputs such as overfill probe signals, ground detection signals, and the like. Independent microprocessor controllers independently evaluate the inputs and each output control signals to close a respective relay when the inputs indicate that fluid transfer may commence. The relays are arranged in series such that both must be closed for a fluid transfer to commence. The control signals from each controller include a static signal and an alternating signal, both of which must be properly output to close its respective relay. Each controller monitors the state of each relay, and discontinues its control signals if either relay appears to be malfunctioning. Each controller runs an different, independently written firmware program to process the detected inputs to prevent a common firmware error. An optical bypass key replaces conventional mechanical keys and transmits an optically encoded signal to the controller for establishing a bypass condition. A preheating circuit is also provided for providing a dynamic voltage supply to standard thermistor probes which may be encountered.

Claims42

Dependent claims

A fluid transfer control apparatus for controlling a transfer of fluid from a fluid source to a receiving container and for detecting and responding to an input signal which indicates whether fluid transfer should occur, the apparatus comprising:

a first switch responsive to a first control signal which switches to a first switch position when the first control signal is received,
a second switch responsive to a second control signal which switches to a first switch position when the second control signal is received, and which is arranged in conjunction with the first switch such that fluid transfer to said container is prevented unless the first switch is in its first switch position and the second switch is in its first switch position;
a first controller which is responsive to the input signal and which outputs the first control signal when the input signal indicates that fluid transfer should occur;
and
a second controller responsive to the input signal which outputs the second control signal when the input signal indicates that fluid transfer should occur.

2 more elements

a first switch having a first switch position;
a second switch having a first switch position and being arranged in conjunction with the first switch such that fluid transfer to said container is prevented unless the first switch is in its first switch position and the second switch is in its first switch position;
a first controller which is responsive to the input signal, and which controls the first switch and detects when the second switch is in the first position, the first controller preventing the first switch from being switched to the first position when the second switch is in the first position and the input signal does not indicate fluid transfer should occur;
and
a second controller which is responsive to the input signal, and which controls the second switch and detects when the first switch is in the first position, the second controller preventing the second switch from being switched to the first position when the first switch is in the first position and the input signal does not indicate that fluid transfer should occur.

2 more elements

A method of controlling fluid transfer control apparatus for transferring fluid from a fluid source to a receiving container and for detecting and responding to an input signal which indicates whether fluid transfer should occur, the method comprising:

providing a first switch responsive to a first control signal which switches to a first switch position when the first control signal is received;,
providing a second switch responsive to a second control signal which switches to a first position when the second control signal is received;
arranging the first switch and second switch such that fluid transfer to the container is prevented unless the first switch is in its first switch position and the second switch is in its first position;
controlling the output of the first control signal with a first controller which is responsive to the input signal and which causes transmission of the first control signal to the first switch when the input signal indicates that fluid transfer should occur;
controlling the output of the second control signal with a second controller which is responsive to the input signal and which causes transmission of the second control signal to the second switch when the input signal indicates that fluid transfer should occur.

2 more elements

A method of controlling a fluid transfer control apparatus for transferring fluid from a fluid source to a receiving container and for detecting and responding to an input signal which indicates whether fluid transfer should occur, the method comprising:

providing a first switch having a first switch position;
providing a second switch having a first switch position;
arranging the first switch and the second switch such that fluid transfer to said container is prevented unless the first switch is in its first position and the second switch is in its first position;
detecting when the second switch is in the first position;
controlling the first switch with a first controller which is responsive to the input signal and the position of the second switch such that the first switch is prevented from switching to the first position when the second switch is in the first position and the input signal does not indicate that fluid transfer should occur;
detecting when the first switch is in the first position;
and
controlling the second switch with a second controller which is responsive to the input signal and the position of the first switch such that the second switch is prevented from switching to the first position when the first switch is in the first position and the input signal does not indicate that fluid transfer should occur.

5 more elements

a switch responsive to a control signal which switches to a first switch position when the control signal is received, the switch being located such that fluid transfer is inhibited when the switch is not in the first position;
a controller which is responsive to the input signal and which outputs the first control signal when the input signal indicates that fluid transfer should occur, the controller comprising a controller signal receiver by which optical signals can be received and input to the controller, and a controller signal generator by which the controller can cause the generation of an optical signal;
and
a bypass key comprising a bypass key signal generator for generating an optical signal which may be transmitted to the signal receiver from the bypass key with no physical contact and no electrical contact between the generator and the receiver and a bypass key signal receiver by which the bypass key can receive optical signals generated by the controller signal generator, thus allowing two-way communication between the controller and the bypass key.

1 more element

Dependencies are inferred from the claim text.

Fail-safe fluid transfer controller

Life of this patent

Fail-safe fluid transfer controller

Life of this patent

Abstract

Claims42