JPS643028Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an automatic tightening device for gland packing in a valve.

In valves whose valve seats are opened and closed by rotating the stem with a handle or motor, a gland packing is attached and tightened around the stem to prevent fluid leakage. This results in fluid leakage.

Conventionally, to prevent such fluid leaks, the gland packing has been retightened through periodic inspections, but valves installed in nuclear reactors and other places that are dangerous to access must be retightened. Sometimes it is difficult to perform the task.

The present invention uses an automatic retightening device to automatically retighten the gland packing, which synchronizes the tightening of a pair of nuts for tightening the gland packing, thereby ensuring uniform tightening at all times without uneven tightening. It is intended to be constructed so that it can follow the downward movement of the nut upon tightening, even though a torque is applied thereto.

In order to achieve the above object, the automatic gland packing tightening device of the present invention includes a pneumatic cylinder that is automatically reciprocated to rotate a pair of gland packing tightening nuts, and a piston rod in this pneumatic cylinder. The tips of a pair of rotary levers rotationally driven by are connected to a pair of nut rotation ratchet mechanisms respectively installed on the tightening nut, and these ratchet mechanisms are provided with engagement holes into which the nuts are fitted and engaged. It also comprises a ratchet gear with a large number of teeth around its periphery, and a socket that is mounted on the ratchet gear and holds a pawl that engages with the teeth so as to be pressed against the teeth by a spring, The rotary lever is tiltably and slidably connected to the socket.

In such an automatic retightening device of the present invention,
When the rotary lever rotates back and forth due to the reciprocating motion of the pneumatic cylinder, the nut for tightening the gland packing is rotated by the ratchet mechanism and the nut is tightened. At this time, the synchronized rotation of the pair of nuts prevents uneven tightening. However, it is possible to always apply an even tightening torque, and since the rotary lever is connected to the socket of the ratchet mechanism so that it can tilt and slide freely, the ratchet can be prevented even when the nut moves downward as it is tightened. The mechanism can be made to follow.

Embodiments of the present invention will be described in detail below with reference to the drawings.

Figures 1 and 2 show the configuration of the gland packing automatic tightening device according to the present invention, in which 1 is the valve stem that opens and closes the valve seat by rotation by a handle or motor, and 2 is the valve stem. The attached bonnet, 3 is a gland packing installed around the stem and between the bonnet, 4 is a gland bushing, 5 is a gland that presses the gland bushing 3 via the gland bushing 4, and 6 is a gland bushing. Nut 7 for tightening indicates a yoke extending from the bonnet.

The automatic retightening device for tightening the gland packing 3 by screwing the nut 6 is equipped with a double-rod type double-acting pneumatic cylinder 10 attached to the yoke 7 as a driving section. This pneumatic cylinder 1
0 has covers 1 on both ends of the cylinder tube 11.
Drive pressure chambers 15 are installed on both sides of the piston 14 that slides inside the cylinder tube 11.
and a return pressure chamber 16, and both the covers 12,
13 are provided with inlets 17 and 18 for supplying pressurized air to pressure chambers 15 and 16, respectively. Rotary levers 21 and 22 for rotating the nut 6 are rotatably connected by pins 23 and 24 to the tips of rods 19 and 20 that protrude from both sides of the piston 14 through the covers 12 and 13, respectively. .

The rotating levers 21 and 22 are for synchronously rotating a pair of gland tightening nuts 6 and 6.
Each is connected to a ratchet mechanism 30 for rotating the nut. The ratchet mechanism 30 includes a ratchet gear 31 having an engaging hole 32 in the center into which the nut 6 is fitted and having teeth 33 around the periphery;
The socket 34 in this ratchet mechanism 30 is constructed by a socket 34 in which a pawl 35 that is mounted on the ratchet gear 31 and engages with the teeth 33 is held so as to be pressed against the teeth 33 by a spring 36. The rotating levers 21 and 22 are fitted into the grooves 37 provided on the upper surface of the holder so as to be tiltable and slidable,
A retainer plate 38 prevents it from coming off.

Therefore, when the piston 14 of the pneumatic cylinder 10 reciprocates and the rotary levers 21, 22 reciprocate within a certain angle range, the pair of nuts 6, 6 are synchronously rotated and tightened by the nut rotation ratchet mechanism 30. In this case, the rotation levers 21, 22
is fitted into the groove of the socket 34 so as to be tiltable and slidable, thereby simplifying the attachment and detachment of the rotary lever, etc., and also reduces the relative mounting position deviation between the pneumatic cylinder 10 and the nut rotation ratchet mechanism 30. , the downward movement of the ratchet mechanism 30 due to tightening of the nut can be absorbed.

Thus, the nut rotation ratchet mechanism 30
A plurality of pawls 35 are connected to the ratchet gear 3.
By arranging the pneumatic cylinder 10 so as to be out of phase with respect to the first tooth 33, the stroke of the pneumatic cylinder 10 can be reduced, and the entire device can be downsized.

In order to control the drive of the pneumatic cylinder 10, both end covers 12, 1 of the pneumatic cylinder 10 are provided.
3 shows the piston 14 that has reached the stroke end.
Pusher rods 41 and 42 that are pressed by the
1 and 42 are provided with limit switches 44 and 45 that are activated when the piston reaches its stroke end. Note that in place of these limit switches 44 and 45, a switch or the like that magnetically detects the position of the piston 14 may be used.

FIG. 3 shows the configuration of a pneumatic circuit connected to the pneumatic cylinder 10. In the figure, 51 is an air source, 52 is a control unit, and this control unit 52 includes a filter 53, a pressure reducing valve 54 whose pressure can be set arbitrarily, and a drive pressure chamber 15 and a return pressure chamber 16 in the cylinder 10.
The cylinder drive solenoid valve 55 is provided with a cylinder driving electromagnetic valve 55 that can be switched to supply pressurized air to one of the supply channels and to discharge the pressure air from the other. Further, 56 indicates a safety valve, and 57 and 58 indicate speed controllers.

FIG. 4 shows the configuration of the electrical circuit which drives the cylinder driving solenoid valve 55, in which 61 is a power switch, 62 is a relay which operates when the limit switch 45 is closed to close relay contacts 63, 64, and 65, 66 is a solenoid of the solenoid valve 55, 67 and 68 are operation display lamps, and 69 is a counter which counts the number of times the solenoid 66 operates.

According to such an electric circuit, in the pneumatic circuit shown in FIG.
The solenoid valve 55 is switched by the relay contact 64 which is closed by the relay contact 64 , and the pressure fluid is supplied to the flow path to the return pressure chamber 16 and the pressure fluid is discharged from the drive pressure chamber 15 . Further, when the piston 14 reaches the other stroke end and presses the limit switch 44 to open its contact, the relay contact 64 opens and the solenoid valve 5
5 is switched to the return position, pressure fluid is supplied to the flow path to the drive pressure chamber 15, and the return pressure chamber 1
Pressure fluid is discharged from 6.

In such an automatic tightening device, the operating force of the pneumatic cylinder requires a large force in the drive direction to tighten the nut 6, and in the return direction, the pawl 35 of the nut rotation ratchet mechanism 30 resists the pressing force of the spring 36. A small force to overcome the tooth 33 is sufficient. Taking these characteristics into consideration, it is possible to attach a return spring to the return pressure chamber 16 in the pneumatic cylinder 10 and return it by its biasing force without supplying pressure air to the return pressure chamber 16 in the pneumatic cylinder 10. It is also possible to use a cylinder with a reduced return force as shown. Pneumatic cylinder 70 in the same figure
In this example, two cylinder tubes 71 and 72 are arranged in series with a partition wall 73 interposed between them, and a rod 75 is installed.
Two pistons 76 and 77 located in each cylinder tube 71 and 72 are attached to the top, and the drive pressure chambers 78 and 79 on one side of both pistons are connected to the rod 75.
The pressure air inlet 83 provided in the cover 81 is communicated with the drive pressure chamber 78 through a through hole 80 bored therein, and the return pressure chamber 84 adjacent to the cover 82 is in communication with the pressure air. Inlet port 8
6 are communicated with each other, but a chamber 85 between the partition wall 73 and the piston 76 is opened to the atmosphere through a through hole 87 provided in the partition wall 73.

Therefore, when pressurized air is introduced from the air inlet 83 of the cover 81 to tighten the nut, the air pressure acts on the two pistons 76 and 77 to drive the rotary levers 88 and 89.
Since the pressurized air from the air inlet 86 is sent to only one return pressure chamber 84, the
I can be brought back to life with just one-half the strength.

FIG. 6 shows another embodiment of the present invention,
Instead of the pneumatic cylinder 10 on both rods in the embodiment of FIGS. 1 and 2, a rod 9 is provided on only one side.
A rotary lever 92 for rotating the nut 6 for tightening the gland is rotatably connected to the tip of the rod 91 by a pin 93, and at an intermediate position of the lever 92.
A rotary lever 95 is rotatably connected to the yoke 7 via a connecting rod 94 that is slidably and slightly rotatably supported.

The rotating levers 92 and 95 are used to synchronously rotate the pair of gland tightening nuts 6 and 6 as in the previous embodiment, and are respectively connected to the nut rotating ratchet mechanism 30.

Also, the force to rotate the gland tightening nut is determined by the length of the rotating lever, the size of the cylinder, and the operating air pressure, but if the force determined by these is restricted to a certain range. As a means for obtaining a larger force, a force multiplier using a planetary gear mechanism may be interposed between the rotary lever and the ratchet mechanism.

[Brief explanation of the drawing]

Fig. 1 is a partially sectional plan view of an embodiment of the present invention (the right half of the ratchet mechanism is a bottom view), Fig. 2 is a side view of the same, Fig. 3 is a configuration diagram of the pneumatic circuit,
FIG. 4 is an electrical circuit diagram, FIG. 5 is a sectional view of a main part of another embodiment, and FIG. 6 is a plan view of still another embodiment. 3...Grand Patsukin, 6...Natsuto, 1
0,70,90...Pneumatic cylinder, 14,7
6,77...piston, 19,20,75,91
... Rod, 21, 22, 88, 89, 92, 9
5...Rotary lever, 30...Ratchet mechanism for nut rotation, 31...Ratchet gear, 32...Engagement hole, 33...Teeth, 34...Socket, 35...
Claw, 36...spring.

Claims (1)

[Scope of utility model registration request] It is equipped with a pneumatic cylinder that is automatically reciprocated to rotate a pair of gland packing tightening nuts, and the tips of a pair of rotary levers that are rotationally driven by a piston rod in this pneumatic cylinder are respectively covered with the tightening nuts. Connected to a pair of nut rotation ratchet mechanisms installed,
These ratchet mechanisms include a ratchet gear that has an engagement hole into which the nut is fitted and has a large number of teeth around its periphery, and a spring-loaded pawl that is fitted over the ratchet gear and engages with the teeth. 1. An automatic retightening device for a valve gland packing, characterized in that the rotary lever is tiltably and slidably connected to the socket, and the rotating lever is tiltably and slidably connected to the socket.