JPS596133B2 - Explosion-proof structure equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flameproof explosion-proof structure for equipment that energizes an actuating element by excitation of an excitation coil.

This type of equipment includes electro-pneumatic converters, electro-pneumatic positioners,
There are solenoid valves, etc., but when these are used in hazardous locations such as explosive gas atmospheres, the equipment is required to have sufficient explosion-proof performance. Various explosion-proof structures have been proposed and implemented to provide this explosion-proof performance, and the pressure-resistant explosion-proof structure of an electropneumatic positioner shown in FIG. 1 is a typical example. To briefly explain the electro-pneumatic positioner shown in the figure, 1 is a main body case, 2 is a terminal board case, and these have a pressure-resistant explosion-proof structure in combination with a main body case cover and a terminal board case cover (not shown). . Reference numeral 3 designates a torque motor, which has a balance beam 5 supported by an excitation coil 4 and a fulcrum plate spring 6, and a cable 8 connecting the excitation coil 4 and the terminal plate 7 is connected to a packing 9.
, is fixed to the terminal plate case 2 by a washer 10 and a fastening member 11, and this pressure-resistant packing retraction structure connects the main body case 1 and the terminal plate case 2 as a pressure-resistant and explosion-proof structure.

A nozzle 12 faces the balance beam 5, and the nozzle 12 and the balance beam 5 constitute a nozzle flapper mechanism.

13 is a supply air pressure piping port, 14 is a fixed throttle for nozzle back pressure, 15 is a pilot valve, 16 is an output pressure outlet, IT is an actuator, and 18 is a feedback mechanism for feeding back the movement of the actuator 17. is configured to transmit the movement of the actuator IT from the feedback lever 19 to the feedback spring 25 via a shaft 20 passing through a bearing 21 having an explosion-proof gap, a link 22, a range adjuster 23, and a link 24.

In such an electro-pneumatic positioner, if the exciting coil 4 is now excited, the balance beam 5 will change depending on the amount of current.
is displaced to the left and blocks the nozzle 12, so the nozzle back pressure increases, and this nozzle back pressure is amplified by the pilot valve 15 to become output pressure, which is guided to the actuator IT. The movement of the actuator IT due to this output pressure is transmitted as a force to displace the balance beam 5 to the right via the feedback mechanism 18, and a force to the left that acts on the balance beam 5 due to the input current to the excitation coil 4. and the movement of the balance beam 5 is stopped. However, in the device configured as described above, the entire main body case 1 and terminal board case 2 must be flameproof and explosion-proof, and the joints between the cases 1 and 2 and these covers, etc. All the parts where the main body case 1 communicates with the atmosphere (the nozzle flapper piping hole 26, the bearing 21, the bleed hole 27, etc.), including the joint between the two cases 1 and 2, are configured to exhibit pressure-resistant and explosion-proof properties. However, satisfying all of these requirements would not only make the entire device larger, heavier, and extremely expensive, but it would also require opening the lid on site to adjust, repair, and replace the nozzle flapper mechanism and feedback mechanism. This is unavoidable, and it is inevitable that the device will become extremely inconvenient to handle.

In order to solve the above-mentioned difficulties, the present invention provides a device that energizes a performance element by excitation of an excitation coil as described above, in which only an electric drive member such as an excitation coil is fixed in a closed container, and the excitation A transmission shaft that transmits the mechanical displacement of the movable member operated by the excitation of the coil to the operating element in the housing integrally formed with the sealed container is connected to the outlet hole in the wall of the sealed container between the inner surface of the outlet hole and the inner surface of the outlet hole. It is characterized by being installed through it with an explosion-proof gap.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings. In FIG. 2, reference numeral 30 is a drive member case made of a closed container for accommodating an electrical drive member 33, and 31 is a terminal made of a closed container. The plate case 32 is a housing that accommodates the actuating element 34 that is energized by the electric drive member, and the housing 32 is integrally connected to the drive member case 30, and the drive member case 30 is connected to the terminal plate. Case 31 is the first
They are connected in a pressure-proof and explosion-proof manner using the same pressure-proof packing retraction structure as shown in the figure.

The electric drive member 33 includes a torque motor 35 having movable members such as an excitation coil 36 and a balance beam 37 supported by a fulcrum plate spring 38, and the excitation coil 36 and the terminal plate 39 are connected to the drive member case 30. and terminal board case 31
It is connected by a cable 40 through the connection part with.

The shaft 42 transmits the mechanical displacement of the balance beam 37 to the main lever 41 in the actuating element 34 in the housing 32, and the shaft 42 is connected to the outlet hole 43 in the wall of the closed container constituting the driving member case 30.
It penetrates through with an explosion-proof gap placed between it and the inner surface of the outlet hole, and specifically can have a structure as illustrated in FIGS. 3 and 4.

In FIG. 3, the transmission shaft 42 inserted into the lead-out hole 43 is
It is provided with tip metal fittings 42a, 42a for connecting with the leaf springs 44, 44 at both ends, and is provided with stoppers 45, 45 in the middle, one tip metal fitting 42a is used as the balance beam 37, and the other tip metal fitting is used as the main body. It is brought into contact with the lever 41.

The leaf spring 44 holds the transmission shaft 42 with an explosion-proof gap 46 between it and the inner surface of the outlet hole, and has not only a shape having a circular seat portion 44a and a radial spring portion 44b as shown in FIG. It can also be formed into a simple plate shape that straddles the outlet hole 43, and a slide bearing can also be used instead of the plate spring. A nozzle 47 facing the main lever 41 constitutes a nozzle flapper mechanism that works together with the main lever 41 to convert displacement into pressure, and is used for nozzle back pressure in an auxiliary plate 48 that serves both for pneumatic piping and for mounting a pilot valve. It is connected to a supply air pressure piping port 50 via a fixed throttle 49, and the back pressure of the nozzle is amplified by a pilot valve 51 attached to an auxiliary plate 48 and guided from an output pressure outlet 52 to an actuator 53. Connected.

A feedback mechanism 54 that feeds back the movement of the actuator 53 has substantially the same configuration as that shown in FIG. Although this is transmitted to the yield back spring 58, there is no need for a pressure-resistant and explosion-proof structure when leading the shaft 56 and the like out of the casing 32.

Note that the driving member case 30 and the terminal plate case 31 do not necessarily have to be connected in the illustrated state, and can be overlappingly connected in any direction to reduce the overall size. There is no problem even if it is a mold or a rotating type.

In the figure, 59 indicates the fulcrum of the main lever 41. In the electropneumatic positioner having the above configuration, the exciting coil 3
6 is excited, the transmission shaft 42 moves to the right along with the right movement of the balance beam 37, and this movement is transmitted to the main lever 41. This increases the back pressure of the nozzle 47, and the back pressure is transferred to the pilot valve 51. The force is amplified and applied to the actuator 53, and the movement of the actuator 53 is applied as a force to move the upper end of the main lever 41 to the right by the feedback mechanism 54, thereby stopping the balance beam 37 from moving to the right.

As described in detail above, in the present invention, the components of the device are divided into an electric drive member constituted by a torque motor etc. and an actuating element energized by the electric drive member, and only the electric drive member is pressure resistant. The structure is such that the movement of the driving member is transmitted to the actuating element by a transmission shaft held in the sealed container through an explosion-proof gap, so that the movement of the driving member is transmitted to the actuating element by a transmission shaft held in the sealed container through an explosion-proof gap. The volume is small, so the overall size and weight can be reduced, and
The explosion-proof side and non-explosion-proof side can be mechanically connected by simply creating a lead-out hole of a specific size in the wall of the sealed container and inserting the transmission shaft, making the structure for this connection extremely simple. This greatly simplifies the configuration of the device, and there is no need to make the casing containing the operating elements flameproof and explosion-proof, making it possible to open the lid and adjust and repair the components installed there even in hazardous locations. We can provide extremely useful equipment that can be easily maintained and managed.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional electropneumatic positioner, FIG. 2 is a sectional view of a device according to the present invention, FIG. It is a front view of a leaf spring. 30... Drive member case, 32... Housing, 33... Electric drive member, 34...
- Operating element, 36... Excitation coil, 37...
... Balance beam, 42 ... Transmission shaft, 43
... Lead hole, 46 ... Explosion-proof gap.

Claims (1)

[Claims] 1. In devices that energize actuating elements by excitation of an excitation coil, only the excitation coil, movable members that are directly actuated by excitation of the excitation coil, and electrical drive members such as cables connecting the excitation coil and the terminal plate are common. another actuating element that is indirectly actuated via the movable member is provided in a non-explosion-proof housing connected to the sealed container, and the mechanical displacement of the movable member is controlled. 1. A pressure-resistant and explosion-proof construction device, characterized in that a transmission shaft for transmitting data to an operating element inside a housing is installed through an outlet hole in a wall of a sealed container with an explosion-proof gap between the inner surface of the outlet hole and the outlet hole.