| 摘要 |
In a control system for delivery of steam at a predetermined pressure to the head of an oil well for use in an open orifice bottom hole heater, a boiler, remote from the well head, is connected by a steam delivery line through a series of valves with a steam pipe extending downwardly into the well to the orifice location near the bottom. In the steam delivery line is a main valve, downstream of which is a pressure regulator and upstream of which is a back pressure regulator. A sensing pressure line from the pressure regulator taps into the delivery line near the well head and a control line from the pressure regulator connected with the main valve control. A back pressure line from the back pressure regulator connects with the delivery line near the boiler and a control line from the back pressure regulator connects with the main valve control. Simultaneous control by the two regulators maintains a constant preset pressure at the well head thereby to maintain a fixed constant temperature for the crude oil at the bottom of the well.
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