摘要 |
<p>A dynamic seal (36) is provided between a rotatable ball control member (24) and a noise attenuator (40) in a fluid control valve (10). In one embodiment a noise attenuator is rigidly clamped in the valve body (12) and a floating, spring biased seal is provided in the attenuator and facing the ball. A bi-directional fluid control valve is provided with two rigidly mounted noise attenuators each having a floating, spring biased ball seal. In a second embodiment a noise attenuator is floating, spring biased towards the ball and includes an annular seal retained in the attenuator. Pressure balancing the fluid flow pressure and the spring bias enables substantially zero seal engagement with the ball during ball rotation, while enabling a reliable seal of the ball in the shut-off valve position.</p> |