Space pressurization control system for high containment laboratories
First Claim
1. A system for controlling space pressure in a room at a predetermined level with respect to a reference space, said system comprising:
- (a) volumetric air flow control means for controlling air flow to and from the room and including means for setting the air flow level;
(b) said volumetric air flow means having means for generating an offset in said air flow level to produce a predetermined space pressure level in the room;
(c) differential pressure control means for sensing a change in said space pressure level and generating a control signal having a value corresponding to the change in said space pressure level, and said differential control means being coupled to said volumetric air flow control means and forming a control loop for said volumetric air flow control means; and
(d) said means for generating an offset having means responsive to said control signal for adjusting the offset in said air flow level for restoring the space pressure in the room to said predetermined level.
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Accused Products
Abstract
An apparatus and method for space pressure control in high containment laboratories. The system comprises a volumetric air flow controller and a differential pressure controller. The differential pressure controller couples to the volumetric air flow controller. To establish negative space pressurization in the laboratory, the differential pressure controller generates a variable offset signal for volumetric operation. In response to the offset signal, the volumetric air controller controls the ducted supply air to the laboratory at a set shortfall compared to the ducted exhaust air flow. The shortfall of ducted supply air creates a negative pressure which is also sensed by the differential pressure controller. The differential pressure controller reduces the variable offset signal to zero once the desired negative pressure level is attained. To maintain the negative pressure level, the supply and exhaust air flow rates must remain equal. Any change in the negative pressure level is detected by the differential pressure controller which will generate the offset signal required to restore the negative pressure level. Furthermore, if the negative pressure level is completely lost, either by breach of the laboratory containment barrier or by equipment failure, then the system will automatically revert to volumetric operation using the offset signal.
57 Citations
13 Claims
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1. A system for controlling space pressure in a room at a predetermined level with respect to a reference space, said system comprising:
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(a) volumetric air flow control means for controlling air flow to and from the room and including means for setting the air flow level; (b) said volumetric air flow means having means for generating an offset in said air flow level to produce a predetermined space pressure level in the room; (c) differential pressure control means for sensing a change in said space pressure level and generating a control signal having a value corresponding to the change in said space pressure level, and said differential control means being coupled to said volumetric air flow control means and forming a control loop for said volumetric air flow control means; and (d) said means for generating an offset having means responsive to said control signal for adjusting the offset in said air flow level for restoring the space pressure in the room to said predetermined level. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for controlling space pressure in a room, said method comprising:
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(a) providing an air flow at a selected level for the room; (b) generating an offset in said air flow level until a predetermined space pressure is established for the room; (c) detecting a change in said established space pressure with respect to a reference pressure; (d) generating a variable offset which varies with said detected change in said space pressure; and (e) applying said variable offset to said offset in said air flow level to restore said predetermined space pressure level. - View Dependent Claims (11, 12, 13)
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Specification