| 摘要 |
1,098,808. Gas analysis. O. H. DRAGER [trading as DRAGERWERK HEINR & BERNH DRAGER]. Aug. 11, 1966 [Aug. 11, 1965], No.36081/66. Heading G1B. An apparatus for use in detecting the presence of solid or gaseous foreign constituents in a gas sample comprises a reciprocating bellows pump 3 of which the expansion stroke sucks the sample through a detector tube 4 or dust filter and is produced by spring force, a driving member 2a which is arranged to produce the closing stroke of the bellows pump 3 and which is driven at a linear speed greater than that of the expansion stroke, and means to control a motor 1 driving the member 2a so as to permit the expansion stroke to proceed freely under the spring force. The electrical supply to the motor 1 may be alternatively controlled, by use of a switch 9, by a counting mechanism with a pre-selector 10, by a time switch 11, or by a programme control device 12 to enable measurements to be taken over a specified period or at specified time intervals. A capsule 6 subject to the pressure in the conduit 3a upstream of the pump 3 is provided with contacts 7, 8 which break the motor supply circuit during the expansion stroke of the pump. The motor is also provided with a holding contact (not shown) to ensure that the member 2a always stops in its initial position clear of the bellows. In place of the bellows pump, a spring-loaded diaphragm or piston pump may be employed, and the motor 1 may be replaced by a solenoid or by a clockwork mechanism which latter is described in detail in the Specification. |
