What Is a Wellhead?
The wellhead is the part where the wellbore is connected to the ground and is an important part of the mine production system. It carries many tasks. The choice of the location of the wellhead is greatly affected by the terrain. There should be enough industrial site near the wellhead. Threats of floods, rolling stones, landslides.
- Wellhead Security Door
- In order to ensure the safety of personnel transportation, each wellhead is provided with a safety door, and the air cylinder valve controls the movement of the cylinder to realize the opening and closing of the safety door. After the personnel enters the cage, the safety door is closed, and the shaker is lifted. The position switch feeds back the status of the safety door and the shaker to the signal system of the hoist, so that the signal system has a signal condition, and the signal worker can send a driving signal. The "Coal Mine Safety Regulations" requires that other loads should not be tapped on the direct power supply line of the lifter and the signal device of the main wellhead winch. Therefore, the wellhead safety gate solenoid valve is powered by the wellhead operating system. However, in actual use, the power supply of the wellhead operating system is taken from the distribution line of the underground substation, and there is a case of power failure due to line failure. After the cage is in place, the safety valve cannot operate normally due to the interruption of the control power of the solenoid valve, and personnel cannot enter or exit the cage. In the case where the power supply system cannot be restored for a short time, maintenance personnel need to remove the connection between the safety door and the cylinder, and manually push and pull the safety door to allow people to enter and exit the cage, which is not safe, but also affects the safe operation of the system due to the availability of processing personnel.
- How Safety Doors Work
- The control of the safety valve air control system must cooperate with the wellhead operating system and signal system. After the cage is in place, the wellhead signalman sends a stop signal, and the stop signal is transmitted to the main control system of the elevator via the signal system. After the driver of the elevator stops in time, the wellhead signalman presses the "open safety door" button, and the operating system starts the hydraulic pump station. The reversing valve controls the driving cylinder of the cradle.
- figure 1
- The wellhead safety valve air control system (see Figure 1) uses a two-position five-way double electric control directional valve (3) to control a gas-controlled reversing two-position five-way main valve (4) to realize the action of the safety door cylinder (6). , Drive the cage safety door to run. An inductive position switch is installed on the safety door to monitor the switching status of the safety door. In order to avoid the malfunction of the safety valve after the solenoid valve is powered off, the solenoid valve (3) is a dual electronically controlled solenoid valve. The movement of the spool in each direction must be achieved by the solenoid valves at both ends. When the power is turned off, the main valve (4 ) Without reversing, the safety door is in the previous position. The compressed air in the air control circuit still acts on the cylinder, and the safety door cannot be opened or closed manually. The opening and closing state of the safety door is interlocked with the hoisting system, so the winch cannot operate normally [7] .
- Wellhead safety door emergency operation valve and complete set of equipment, including two-position five-way double electric control directional valve, two-position five-way directional valve and cylinder, the three are connected in sequence. A reversing valve that changes the direction of air pressure. An operating handle for controlling the change of air flow is provided on one side of the reversing valve, so that the wellhead hooker can manually reversing the valve. When the two-position five-way control valve works normally, the two-position five-way control valve can be controlled by changing the different gas paths of the two-position five-way control valve. The two-position five-way control valve is directly connected to the cylinder. Connected to control the direction of movement of the cylinder to control the opening and closing of the safety door. However, when the power is cut off, the two-position five-way dual electronically controlled directional control valve cannot be reversed, which causes the two-position five-way directional control valve and the cylinder to fail to operate, and the air flow in the two-position five-way directional control valve cannot be reversed. The air pressure cannot be changed, and the safety door cannot move normally. At this time, the direction of the air flow can be changed by manually controlling the reversing valve. The role of the reversing valve is to cross-reverse the air flow that originally circulates, that is, the original air inlet line becomes the air outlet line, and the original air outlet line becomes It is an intake pipe, so the direction of the air pressure of the cylinder is changed, the purpose of controlling the safety door to change the opening and closing state is achieved, and the opening and closing can be realized even in the case of power failure. The valve core and the valve body are reformed scientifically and reasonably, so that the two-position five-way valve has the function of the two-position four-way valve. The ingenious design of manual operation mechanism and safety locking mechanism can realize the free commutation of the gas path when the safety valve solenoid valve is powered off, and it is not affected by the initial position of the safety door; when it is not in operation, it has no effect on the original gas control system.