| 摘要 |
A selector valve is disclosed for a breath sampling apparatus which comprises a pair of plate-like members that have a connection with one another for relative edgewise swinging about an axis. Each of the plate-like members has an outer surface and an inner surface which is flat and normal to the axis and which slidably opposes the inner surface of the other member. Each of the plate-like members has a port through it, the ports in the two members being spaced at like distances from said axis. A stop is provided on said members defining a first position wherein the ports are in register with one another, and a second position wherein the ports are spaced apart and wherein the port in said one plate-like member is blocked by the other plate-like member with the port in the other plate-like member open to atmosphere. A biasing spring is provided to bias the plate-like members to one of the positions. A spring bias force selector is provided to adjustably vary the force of the biasing spring.
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