| 摘要 |
747,843. Respiratory appliances. BRITISH OXYGEN CO., Ltd. Nov. 29, 1954 [Dec. 1, 1953], No. 33362/53. Class 81(2). The flowmeter in a gas administration apparatus is provided with a by-pass so that a large amount of gas may be passed to the patient without having to pass it through the flowmeter and the gas flow is controlled by a valve which is so connected to a masking device that the calibrations of the flowmeter are obscured when the by-pass is open. The mask is mechanically connected to the control knob of the valve and may either be in the form of a plate 19 connected directly to the valve spindle 17 so as to be moved sideways across the front of the flowmeter graduations 10 when the valve is moved to the open position or an elongated valve spindle may be mounted at one side of the flowmeter and carry the mask in the form of a radially projecting flag which, as the spindle is turned, rotates from a concealed position to a position in front of the meter. In cases where the flowmeter has a circular or semi-circular dial a mask, rotating with the valve spindle, is made to obscure the dial when the valve is turned to the open position.
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