Valve used pneumatic actuator
Technical field
The present invention relates to valve positioner, particularly about a kind of valve used pneumatic actuator.The present invention is applicable to the pneumatic actuator of overhead valve of pulp digester.
Background technique
In paper technology, digester is the raw material such as wood chip to be become the key equipment of paper pulp by chemical reaction, in order to prevent that in digester, dielectric leakage causes environmental pollution, to the sealability of digester overhead-valve with control reliability very high requirement is arranged.At present, the keying of digester overhead-valve generally adopts pneumatic actuator to control, and pneumatic actuator is by the master control electromagnetic valve, and the source of the gas by master control electromagnetic valve pneumatic actuator reaches the control to the digester overhead-valve.But the working state of existing pneumatic actuator is fully by the master control electromagnetic valve, and when the master control electromagnetic valve received error signal, pneumatic actuator also can drive the digester overhead-valve and produce misoperation, and its safety reliability is poor.
Summary of the invention
The objective of the invention is the problem for the prior art existence, a kind of misoperation of digester overhead-valve, valve used pneumatic actuator that control security is good, reliability is high of preventing is provided.
technological scheme of the present invention comprises housing, cylinder, housing is provided with the link that is fixedly connected with valve, cylinder is fixedly mounted on housing, piston in one end of piston rod and cylinder is fixedly connected with, the other end is fixedly connected with valve rod by the transmission device in housing, mainly to be provided with safety lock on piston rod, this safety lock is by locking bar, lock dog and control cylinder form, lock dog is fixedly mounted on the piston rod end, locking bar is hinged in housing by rotating shaft away from cylinder end, one end of the nearly cylinder end of locking bar and control piston bar is hinged, control piston in the other end of control piston bar and control cylinder is fixedly connected with, the rod chamber of control cylinder is connected with an end of suction tude, the other end of suction tude is connected in the outlet that control latching solenoid valve dead electricity closes, in the rodless cavity of control cylinder, control spring is housed, control cylinder is fixedly mounted on the housing outer wall.
In above technological scheme, be connected in series the pressure switch normally closed interlock on the control power supply of control latching solenoid valve, closing valve position position limit switch normally closed interlock, closing a unlock button switch in parallel on valve position position limit switch normally closed interlock.
In above technological scheme, a unlocking signal switch and block signal switch are installed on the housing in the middle part of locking bar.
Advantage of the present invention is to be provided with safety lock on piston rod, this safety lock is controlled by pressure switch signal and the pass valve position position limit switch semaphore lock of controlled container (digester) pressure sensor, when controlled container (digester) internal pressure surpasses setting pressure or controlled valve closing state, pressure switch and pass valve position position limit switch disconnect, make control latching solenoid valve dead electricity, control spring promotes locking bar and withstands the lock dog lower end surface, safety lock is in blocking, forbid that piston rod moves, prevent the misoperation of digester overhead-valve, its control security is good, reliability is high.
Description of drawings
Fig. 1 is structural representation of the present invention.
Embodiment
Valve used pneumatic actuator as shown in Figure 1, comprise housing 3, cylinder 1, housing 3 is provided with the link that is fixedly connected with valve, cylinder 1 is fixedly mounted on housing 3, piston in one end of piston rod 2 and cylinder 1 is fixedly connected with, the other end is fixedly connected with the valve rod of controlled valve by the transmission device that is arranged in housing 3, piston rod 2 is to the interior indentation of cylinder 1 when the valve closing state, during valve opening state, piston rod 2 is from the interior release of cylinder 1, and the work source of the gas of cylinder 1 is by the master control electromagnetic valve.Be provided with safety lock on piston rod 2, this safety lock is comprised of locking bar 4, lock dog 11 and control cylinder 9, and lock dog 11 is fixedly mounted on piston rod 2 ends, and locking bar 4 is hinged in housing 3 by rotating shaft 8 away from cylinder 1 end, be that rotating shaft 8 is fixedly mounted on housing 3 inwalls, locking bar 4 can rotate in rotating shaft 8.One end of nearly cylinder 1 end of locking bar 4 and control piston bar 10 is hinged, control piston in the other end of control piston bar 10 and control cylinder 9 is fixedly connected with, the rod chamber of control cylinder 9 is connected with an end of suction tude, the other end of suction tude is connected in the outlet that control latching solenoid valve dead electricity closes, close when namely controlling the latching solenoid valve dead electricity cut off source of the gas, open on the port that is communicated with source of the gas when electric.Control spring 5 is housed in the rodless cavity of control cylinder 9, control cylinder 9 is fixedly mounted on housing 3 outer walls, when control latching solenoid valve dead electricity, the rod chamber of control cylinder 9 and source of the gas cut off, control spring 5 promotes control piston bar 10 and locking bar 4 is withstood on the lower end surface of lock dog 11, lock piston bar 2, even when the master control solenoid valve sends error signal, the digester overhead-valve can misoperation yet.
Be connected in series the pressure switch normally closed interlock on the control power supply of control latching solenoid valve, closing valve position position limit switch normally closed interlock, closing a unlock button switch in parallel on valve position position limit switch normally closed interlock.When the digester internal pressure surpassed setting pressure, the pressure transducer output signal disconnected the normally closed interlock of pressure switch, and safety lock is in the lock state.Described pass valve position position limit switch normally closed interlock, the switch contacts that disconnects when namely valve closing puts in place, this moment, safety lock was in the lock state.The unlock button switch is the normally open contact switch, opens before valve first by the unlock button switch, and its normally open contact is closed, makes safety lock be in released state.
One unlocking signal switch 6 and block signal switch 7 are installed on the housing 3 at locking bar 4 middle parts, when safety lock is in released state, unlocking signal switch 6 is connected the release pilot lamp power, and when safety lock was in the lock state, block signal switch 7 was connected the locking pilot lamp power.