Method and apparatus for reducing free flow risk
First Claim
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1. A method for reducing a risk of external pressure-induced free flow through a pump having an inlet and an outlet comprising:
- establishing a fluid communication between the pump inlet to a first side of a pressure responsive member;
establishing a fluid communication between the pump outlet and a second side of the pressure responsive member independent of a pump outlet line;
continuously sensing a pressure difference between an inlet pressure and an outlet pressure with the pressure responsive member;
mechanically communicating the pressure difference to a flow restricting element associated with the pump outlet line, wherein the flow restricting element does not inhibit the fluid communication between the pump outlet and the pressure responsive member; and
activating the flow restricting element when the inlet pressure exceeds the outlet pressure to increase a resistance to a fluid flow through the pump outlet line in proportion to the pressure difference between the inlet pressure and the outlet pressure.
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Abstract
A technique for reducing the risk of free flow through a pump is disclosed. The technique includes sensing a pressure difference between the pump inlet and outlet. The pressure difference is mechanically communicated to a flow restricting element. The flow restricting element increases resistance to flow exiting the pump outlet in a relation to the pressure difference present between the pump inlet and pump outlet.
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Citations
16 Claims
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1. A method for reducing a risk of external pressure-induced free flow through a pump having an inlet and an outlet comprising:
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establishing a fluid communication between the pump inlet to a first side of a pressure responsive member; establishing a fluid communication between the pump outlet and a second side of the pressure responsive member independent of a pump outlet line; continuously sensing a pressure difference between an inlet pressure and an outlet pressure with the pressure responsive member; mechanically communicating the pressure difference to a flow restricting element associated with the pump outlet line, wherein the flow restricting element does not inhibit the fluid communication between the pump outlet and the pressure responsive member; and activating the flow restricting element when the inlet pressure exceeds the outlet pressure to increase a resistance to a fluid flow through the pump outlet line in proportion to the pressure difference between the inlet pressure and the outlet pressure. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An apparatus for reducing free flow risk comprising:
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a pump having a pump inlet and pump outlet, configured to transfer fluid received from the pump inlet to the pump outlet; a pressure responsive member in fluid communication with the pump inlet and with the pump outlet independent of a pump outlet line, the pressure responsive member operating to respond to a pressure difference between the pump inlet and the pump outlet; and a flow restrictor mechanically coupled to the pressure responsive member that limits fluid flow through the pump outlet line, wherein the flow restrictor does not inhibit the fluid communication between the pump outlet and the pressure responsive member and is configured to increase a resistance to a fluid flow through the pump outlet line in proportion to the pressure difference between the pump inlet and the pump outlet when an inlet pressure exceeds an outlet pressure. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
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16. An apparatus for reducing free flow risk through a pump having a pump inlet and a pump outlet comprising:
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means for sensing a pressure difference between the pump inlet and the pump outlet; means for mechanically communicating the sensed pressure difference to a flow restricting element associated with a pump outlet line; and means for increasing a resistance to fluid flow through the pump outlet line through the flow restricting element that is responsive to the means for mechanically communicating the sensed pressure difference when an inlet pressure exceeds an outlet pressure, wherein the flow restricting element does not inhibit the means for sensing a pressure difference and is configured to increase the resistance to flow in proportion to the sensed pressure difference.
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Specification