Asymmetric purge air system for cleaning a lens
First Claim
1. An instrument for sensing radiation representative of a parameter in a particle suspension and for providing an output indicative of the parameter, the instrument receiving a supply of pressurized fluid, comprising:
- port means disposed on the instrument and opening to the parameter source for receiving the radiation;
sensing means coupled to the port means for sensing the received radiation and for providing the output;
window means disposed between the port means and the sensing means for transmitting the radiation therethrough and for shielding the sensing means from the particle suspension, the window means having a window surface with a central axis normal to the window surface, for transmitting radiation to the sensing means exposed to the suspension; and
purge means disposed in the instrument for receiving the pressurized fluid and having openings arranged around the circumference of the window surface for directing flows of the pressurized fluid having an axially asymmetric flow pattern onto the window surface, generating an unstable flow pattern of the pressurized fluid on the window surface such that particles are removed from substantially all of the window surface.
1 Assignment
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Accused Products
Abstract
A purging air flow system for passing air over a lens to keep it clean and free from particulate contaminants and also for providing a positive flow of air away from the lens has baffles which cause a flow across the lens that is not symmetrical to avoid a dead air or stagnation zone in the center of the lens. The air supply used for such purging is controlled adequately so the flow changes direction and particles are removed from the main flow of purge air by inertial separation prior to the time the air contacts the lens. Such air entrained particles might otherwise deposit on the lens. A flow control orifice also may provide a secondary flow to carry the particles separated from the main flow out of the flow passageway.
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Citations
9 Claims
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1. An instrument for sensing radiation representative of a parameter in a particle suspension and for providing an output indicative of the parameter, the instrument receiving a supply of pressurized fluid, comprising:
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port means disposed on the instrument and opening to the parameter source for receiving the radiation; sensing means coupled to the port means for sensing the received radiation and for providing the output; window means disposed between the port means and the sensing means for transmitting the radiation therethrough and for shielding the sensing means from the particle suspension, the window means having a window surface with a central axis normal to the window surface, for transmitting radiation to the sensing means exposed to the suspension; and purge means disposed in the instrument for receiving the pressurized fluid and having openings arranged around the circumference of the window surface for directing flows of the pressurized fluid having an axially asymmetric flow pattern onto the window surface, generating an unstable flow pattern of the pressurized fluid on the window surface such that particles are removed from substantially all of the window surface. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An instrument for sensing radiation representative of a parameter in a particle suspension and for providing an output indicative of the parameter, the instrument receiving a supply of pressurized fluid, comprising:
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port means disposed on the instrument and opening to the parameter source for receiving the radiation; sensing means coupled to the port means for sensing the received radiation and for providing the output; window means disposed between the port means and the sensing means for transmitting the radiation therethrough and for shielding the sensing means from the particle suspension, the window means having a window surface for transmitting radiation to the sensing means exposed to the suspension; and purge means defining a plurality of radially spaced ports around the periphery of the window surface and means for providing a flow of the pressurized fluid inwardly from the ports toward center portions of the window surface, the ports being asymmetrical for providing an unstable flow of the pressurized fluid onto the window surface such that particles are removed from substantially all of the window surface. - View Dependent Claims (8, 9)
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Specification