| 摘要 |
A valve assembly (6) comprises a valve stem (21) with a resilient proximal seal member (25) and a distal seal member (28) disposed around the stem. The proximal and distal seal members are axially separated from one another along the valve stem. A housing defines a valve chamber in which the valve stem is confined so as to be axially displaceable within the valve chamber. The housing defines a first portion (41) of the valve chamber in which the proximal seal member resides and a second portion (42) of the valve chamber in which the distal seal member resides. The housing further defines a cross-bore chamber(12) which opens into the valve chamber in a third portion (43) between the first and second portions. The third portion has a minimum cross-sectional diameter greater than the cross-sectional diameter of the first portion, and preferably larger than the uncompressed diameter of the proximal seal member. During assembly, as the proximal seal on the valve stem passes the cross-bore, risk of damage to the proximal seal by machined edges of the cross-bore/valve chamber is reduced or avoided. |
