Hole trepanning and suction device for agar coating - esp. on glass plate, prevents loosening of surrounding coating from plate

摘要

Hole-punching and suction device for the punched plate agar diffusion method comprises a trepanning tube and suction appts. for removing the trepanned agar plate. The suction appts. consists of a hollow cylinder (2), axially displaceable coaxially in the trepanning tube (1), and connected to a vacuum pump. The trepanning tube (1) pref. has suction openings (8) through which external air is drawn in, to flow down the annular space (9) between cylinder and tube, change direction through 180 deg. and leave towards the vacuum pump. Pref. the hollow cylinder (2) has a compression spring (10) thrusting against a threaded ring (7) screwed inside the tube (1) to provide height adjustment. Useful for the quantitative determn. of antibiotics in liquids obtained from human or animal organisms. The flow of air downwards inside the tube prevents lifting of the coating from the glass plate and thus prevents unreliable readings.