1 Overview
The function of the hand-pneumatic pressure reducing and overflow valve (pressure regulating valve) in the ground BOP control device is to control the pressure of the annular blowout preventer and reduce the high pressure oil (21Mpa) in the accumulator to a lower pressure (usually It is 10.5Mpa). In addition, the valve can also automatically overflow, is a pressure relief valve.
2. Main technical parameters
Name:Hand pneumatic pressure regulator
Model:JYSQ21-25
Nominal Pressure (MPa):21
Nominal Diameter (mm):25
Flow(L/Min):160
Gas source Pressure (MPa):0.65~0.8
Jobs Pressure (Mpa):0~21
Adjustment Range (Mpa):0~18
Weight:28KG
3. Structure
As shown in the figure, JYSQ21-25B type manual pneumatic pressure regulating valve is mainly composed of the following parts:
Handwheel, adjusting screw, locking handle, spring guide plate, spring adjustment cover, large spring, small spring, tray, guide sleeve, spacer sleeve, upper mold cover, guide sleeve, lower film cover, connecting rod, sealing box, Springs, pressure relief seal rings, oil inlet plungers, wave springs, oil drain seal rings, oil inlet flanges, valve bodies, lower plugs, oil outlet flanges.
The sealing box is equipped with a pressure reducing sealing ring and an oil drain sealing ring. There is a spring between the decompression sealing rings, and a wave spring is installed between the oil drain sealing rings. Each sealing ring contacts the oil inlet plunger to form an annular flat sealing belt. The oil inlet plunger is provided with an oil inlet and an oil outlet, and a pressure oil outlet after decompression is provided above the valve body. The outlet pressure adjustment after decompression is achieved by rotating the handwheel to compress the large spring and the small spring.
When adjusting the pressure, the handwheel rotates clockwise to become a compression spring. As the compression of the spring increases, the outlet pressure increases. On the contrary, if the handwheel rotates counterclockwise, the outlet pressure will decrease. After the outlet pressure is adjusted, lock the adjusting screw with the lock handle.
4. Working principle
As shown in the figure, the pressure oil P1 entering from the oil inlet passes through the throttle K (the gap formed between the oil inlet on the oil inlet plunger and the pressure reducing seal ring) to decompress to P2 and enter the valve cavity. At this time, the oil outlet does not open. Under the action of hydraulic pressure, the sealing box moves up to seal the oil inlet and the drain port, and maintains the pressure in the valve cavity after decompression is P2. The sealing box is under the spring force and hydraulic pressure. Under the action, in a state of equilibrium.
Once the oil outlet is opened, due to the hydraulic power generated by the flow of the liquid, the sealed box moves down (the spring is extended and the spring force is reduced), and the adjusted orifice K reappears. The pressure oil is continuously discharged from the oil outlet after decompression. At this time, the sealed box is in a new balance under the reduced spring force, hydraulic pressure and hydraulic power.
If the oil outlet is closed, the hydraulic power disappears, the sealing box loses balance and moves upward to seal the oil inlet and drain. The spring returns to its original compression, so that the sealed box reaches its original equilibrium state.
Due to the increase in pressure at the oil outlet, the pressure in the valve cavity also increases, destroying the balance of the sealed box. The sealed box is moved up to open the original closed drain port to overflow. After causing the pressure oil in the valve cavity to reach the original decompression value, the drain port is closed and the sealed box returns to the original equilibrium state. This is the situation when the Annular BOP is closed and the drill tool needs to be lifted and passed through the drill pipe joint.
When the drill pipe joint enters the sealing rubber core of the awakening blowout preventer, the drill pipe joint larger than the diameter of the drill pipe squeezes the rubber core, and the rubber core is forced to move down by the piston, and the inlet rigid volume decreases, which makes the pressure relief valve When the outlet pressure rises, the seal box moves up, so that the drain port opens and overflows until the outlet pressure is restored to the original setting, so as to protect the sealant core of the annular blowout preventer from damage.
When the drill pipe joint passes through the rubber core of the annular blowout preventer, the diameter of the drill pipe joint is larger than the diameter of the drill pipe, which causes the drill pipe joint to squeeze the rubber core outward, causing the pressure at the outlet of the relief valve to increase. . However, as long as the pressure increases, the original balance with the spring force will be destroyed, and the seal box will be lifted up. As a result, the drain seal ring at the lower part of the seal box and the drain port on the oil inlet plunger appear. Crescent-shaped gap. At this time, part of the pressure oil in the valve cavity will overflow from this gap and return to the oil tank, thereby reducing the outlet pressure of the valve. Until it is balanced with the set spring force again, and the sealed box moves downwards, the crescent-shaped gap disappears and the overflow stops. In this way, the outlet pressure of the valve can always be maintained at the set value, so as to protect the sealant core of the annular blowout preventer from damage.
5. Features and instructions
In the process of pressure regulation, the pressure rises in a stepped manner, but it is more stable when the pressure is reduced.
When leaving the factory, the outlet pressure of the pressure reducing and overflow valve is adjusted to 10.5Mpa. If the user needs a lower pressure, he can turn the handwheel 1 counterclockwise to reduce the outlet pressure.
When adjusting the pressure manually, turn the hand wheel on the upper end of the pneumatic pressure regulating valve to adjust the output pressure to the set pressure. Rotate downward to increase output pressure, and rotate upward to decrease output pressure. When adjusting pneumatic pressure, first, when the air pressure is zero, manually adjust the pressure until the output pressure is the required set pressure, lock the handle, and then turn the adjustment knob on the remote console or the driller's console, that is The control pressure of the annular blowout preventer can be adjusted.
In the system, the oil inlet of the pressure relief valve is equipped with an oil filter. Please pay attention to cleaning the oil filter to prevent dirt from entering the valve and hindering the normal operation of the valve.
When the oil pressure at the oil inlet of the valve changes, the outlet pressure of the valve is not affected. When the pneumatic pressure regulation fails (for example, the air pressure is zero due to the burst of the air pipe), the outlet pressure will automatically return to the initial setting value manually set to ensure safety.
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