Micro-dosing valve for small quantities of gas, used in connection with measurements of carbon dioxide uptake by plants, includes numerous design features enhancing precision of delivery and actuation

摘要

The lower section (1) of the valve includes an axial bore (3) forming a gas passage. This accepts and aligns a cylinder end bolt (5) in its lower internal thread. The bolt includes the valve gas inlet (18) and a connecting tube (6). This tube has self-centering play within the outer axial bore (3). Its other end enters a plug (7) into which an upper, conical valve seat is formed. The bore (3) continues in the upper section (2), which is screwed to the lower (1). It accepts and guides a longitudinally-sliding valve rod (12). A disc support (13) is located in a bore of the upper section for the Bellville spring washer pack (14), of which the upper end is supported on a shoulder (15) of the bore. Passing through the disk support, the valve plug is formed by a pointed, pencil-like rod, which enters the valve seat. With its base section (20) the actuator is screwed onto the upper section (2). The top end of the actuator (22) is connected to the top of the valve rod assembly.