| 摘要 |
<p>An automatic reset pneumatic timer for control of a motor valve on a lift gas injection system of an oil and gas well or a plunger-pump well installation in an oil or gas well. The pneumatic timer includes means for connecting the timer with a source of air or gas pressure, means for connecting the timer with the operator of a motor valve, a cycle timer including a pneumatic valve, an on timer including a pneumatic valve, a pneumatic relay valve connected between the on timer and the motor valve for directing a pressure signal to the motor valve when the on timer is operating, and a pneumatic automatic reset valve connected with the source and the cycle timer and on timer for resetting both timers to initiate a new sequence of operation when the prior sequence is completed. One form of the pneumatic timer operates solely in response to the cycle timer and on timer of the system. Another form of the pneumatic timer includes a trip valve and a shut-off-on-arrival valve for operating the pneumatic timer in response to movement of a plunger in a tubing string of a well. Both forms of the timer pneumatically control the length of time a motor valve is held open and the time period between each operation of the motor valve.</p> |
