| 摘要 |
<p>Fluid in the relatively long lines (22, 24) between a control valve (16) and a fluid actuator (14) can become overly viscous in cold weather. Herein, fluid is circulated through such lines (22, 24), at least during cold weather, even when the fluid actuator (14) is not being used. This flowing is discontinued in response to shifting of the control valve (16) to a position where it motivates the actuator (14) and in response to pressure in the circulating path (20) exceeding a selected level. </p> |
