| 摘要 |
The device described comprises a piston valve pump (2, 3) and a valve block (5) which has an inlet and an outlet valve (6, 7) and which can be mounted on a reservoir. In order to compensate the difference in pressure between the reservoir and the surrounding atmosphere produced when liquid is removed from the hermetically sealed reservoir, the valve block (5) also has a ventilating valve (24) which on the one hand admits ambient air into the reservoir and on the other hand reliably prevents the escape of even minute quantities of liquid during prolonged standing. |
