JP3922548B2 - Flame detection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a flame detection device including a flame detection unit in which an ultraviolet sensor is housed in a casing and unitized, and a unit holder to which the flame detection unit is detachably attached.
[0002]
[Related background]
An ultraviolet ray detection discharge tube (UV tube), which is a kind of ultraviolet sensor, encloses a pair of discharge electrodes that generate ultraviolet rays upon receiving ultraviolet rays in a cylindrical glass tube, and leads the discharge electrode comprising a pair of thin metal wires. The terminal is derived from one end thereof, and is used as a flame detector for monitoring the combustion state of the gas burner, for example. A flame detection apparatus using such a UV tube is introduced in detail in Japanese Patent Laid-Open No. 5-12581.
[0003]
Typically, Japanese Patent Publication No. 44-1039 discloses the construction of a discharge tube for ultraviolet detection, and Japanese Patent Publication No. 47-7878 discloses its detection circuit.
[0004]
[Problems to be solved by the invention]
By the way, it is conceivable that this type of UV tube is housed in, for example, a cylindrical cover body, and the UV tube external connection terminal is provided at the rear end of the cover body to form a unit. According to the flame detection unit unitized in this way, for example, there is no possibility that the glass tube of the UV tube will be inadvertently damaged during maintenance, or the lead terminal may be broken. It becomes possible.
[0005]
However, when the flame detection unit has a round bar-like appearance and is configured with a pair of external connection terminals arranged at the rear end thereof, the pair of external connection terminals is usually symmetrical about its axis. It is difficult to distinguish these polarities easily. In particular, when the flame detection unit is detachably mounted on the unit holder provided in the flame detection device, when the flame detection unit is rotated around its axis and attached in the opposite direction, the pair of external connection terminals respectively There is a possibility that the connection between a pair of press contact terminals provided in press contact is reversed.
[0006]
The present invention has been made in view of such circumstances, and its purpose is to align the direction of the unit holder without reversely connecting a pair of external connection terminals provided at the rear end of the flame detection unit. It is an object of the present invention to provide a flame detection device that can be securely attached.
[0007]
[Means for Solving the Problems]
In order to achieve the above-described object, the flame detection device according to the present invention includes a discharge tube for detecting ultraviolet rays in a casing made of a cylindrical body having a light receiving window formed at the tip, and the ultraviolet detection at the rear end of the casing. A flame detection unit provided with a pair of external connection terminals connected to the discharge tube symmetrically around the axis of the casing, a receiving part into which the tip of the flame detection unit is fitted, and the receiving part A unit holder provided with a pair of press contact terminals that are respectively press-contacted to the external connection terminals of the flame detection unit, which is mounted and fitted with a tip portion fitted into the receiving portion. ,
In particular, the pair of external connection terminals are spatially partitioned in the flame detection unit and protruded from the rear end portion of the casing to provide a plate-shaped partition wall, and a deformed portion on one side of the partition wall On the other hand, on the unit holder, the partition wall portion of the flame detection unit, which is mounted by fitting a tip portion into the receiving portion, is a side opposite to the side portion on which the deformed portion is provided. It is characterized in that a guide groove that can be fitted only from the portion is provided.
[0010]
That is, according to the present invention, a partition wall portion is provided at the rear end portion of the flame detection unit so as to separate the pair of external connection terminals from each other by dividing the rear end portion into two semicircular regions through the center. And provided with a deformed portion on one side of the partition wall, and provided with a guide groove that allows the unit holder to be fitted only from the other side where the deformed portion is not provided. And the guide groove, the direction in which the flame detection unit can be attached to the unit holder is restricted around its axis.
[0011]
In the case where the unit holder includes an arc-shaped holding frame that holds the peripheral wall of the flame detection unit that is mounted with the tip portion fitted into the receiving portion, the holding frame and the peripheral wall of the flame detection unit It is also useful to provide a projection, a groove (notch) or the like for restricting the direction in which the flame detection unit can be attached to the unit holder around its axis.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a flame detection apparatus according to an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1 in an exploded perspective view, the flame detection apparatus is schematically a flange unit 20 attached to a viewing window (not shown) such as a gas burner, and a unit holder attached to the flange unit 20. 30. A shutter unit 40 incorporated in the lower part of the unit holder 30 is provided. 2, the flame detection unit 10 is detachably mounted on the upper surface of the unit holder 30 and the unit holder 30 and the shutter unit 40 are collectively attached by a cover 50 as shown in FIG. Used to cover. The shutter unit 40 is provided opposite to the tip of the flame detection unit 10 mounted on the unit holder 30 and includes a shutter 41 made of a leaf spring body that blocks the incidence of ultraviolet rays on the flame detection unit 10. And a drive mechanism 32 of the shutter 41 composed of an electromagnetic coil.
[0013]
Here, as shown in FIG. 3, the flame detection unit 10 holds, for example, an ultraviolet ray detection discharge tube (UV tube) 1 assembled to a holder (tube holder) 2 and holds it. It has a structure that is housed inside the elongated cylindrical casing 3 together with the body 2. The casing 3 is made of a light-shielding member having a light receiving window 3a at its tip, and is made of a truncated cone-shaped cylinder whose diameter is slightly reduced toward the tip. And while protecting the UV tube 1 accommodated in the inside from external force, it plays the role which blocks | prevents incidence | injection of the light (ultraviolet ray) other than the said light reception window 3a. An external connection terminal 4 connected to a pair of discharge electrodes of the UV tube 2 is provided on the rear side surface (rear end portion of the casing 3) of the holding body 2 that closes the rear end portion of the casing 3. ing.
[0014]
The UV tube 1 has a structure in which a pair of discharge electrodes (not shown) are enclosed in a cylindrical glass tube 1a, and lead terminals 1b of the discharge electrodes are led out from the rear ends thereof. The holding body 2 is made of, for example, a synthetic resin made by injection molding, and includes a disk-shaped base portion 2a to which the UV tube 1 is attached at one end portion, and the other end portion at the other end portion. It has a structure provided with a disk-shaped terminal block 2b on which an external connection terminal 4 for the lead terminal 1b is mounted. The disc-shaped base portion 2a and the terminal block portion 2b are provided coaxially so as to face each other via a plate-like connecting portion 2c.
[0015]
The connecting portion 2c secures a space into which the sealing projection 1c of the UV tube 1 attached to the base portion 2a enters. Further, in the space formed by the connecting portion 2c, the lead terminal 1b of the UV tube 1 held by the base portion 2a and the connecting piece of the external connection terminal 4 attached to the terminal base portion 2b are electrically resistant. They are connected to each other through the body 5 and lead wires. Then, the UV tube 1 held by the holding body 2 and connected to the external connection terminal 4 is packaged by fitting a cap-like packing body 6 at the tip thereof into the casing 3. . The cap-shaped packing body 6 is made of silicone rubber or the like, and plays a role of hermetically sealing between the outer peripheral surface of the UV tube 1 and the inner peripheral surface of the casing 3. In addition, an opening 6 a that opens with the tip of the UV tube 1 as a light receiving window is provided at the tip of the packing body 6.
[0016]
Now, in the flame detection unit 10 packaged in this way, the present invention is characterized in that a plan view, a front view and a rear view of the flame detection unit 10 are shown in FIGS. 4 (a), (b) and (c). As shown in the end views, the protruding lengths of the pair of external connection terminals 4, 4 provided side by side at the rear end of the casing 3 are different in the axial direction of the casing 3, in other words, the pair of external connection terminals. The terminal 4 is provided with a step. Further, a partition wall portion 7 is provided at the rear end portion of the casing 3 to partition the rear end portion into two semicircular regions to isolate the pair of external connection terminals 4 and 4 from each other. It is characterized in that a deformed portion comprising a thick portion 7a is provided only on one side.
[0017]
That is, the terminal block 2b of the holding body 2, which is the rear end portion of the flame detection unit 10 in this embodiment and closes the rear end portion of the cylindrical casing 3, passes through the axial center of the rear end portion. A plate-like partition wall 7 is provided to divide the portion into semicircular regions. The pair of external connection terminals 4 and 4 are separately provided in two regions partitioned by the partition wall portion 7. In particular, these external connection terminals 4, 4 are provided in steps by changing the protruding length in the axial direction from the rear end portion of the casing 3, whereby the polarities thereof are distinguished in appearance. Further, a thick portion 7a is formed on one side of the partition wall portion 7, and the orientation of the flame detection unit 10 is clearly indicated by the presence of the thick portion 7a.
[0018]
Furthermore, a ring-shaped flange 8 is formed so as to protrude from the substantially central portion of the peripheral wall surface of the casing 3 over the entire circumference, and the sectional structure of the casing 3 is shown in FIG. As shown, a linear cut-out portion (D cut surface) 8a and a groove-shaped cutout portion 8b are provided corresponding to the direction of the partition wall portion 7, respectively. These cut-out portions (D-cut surfaces) 8a and cut-out portions 8b are also indices indicating the direction around the axis of the flame detection unit 10.
[0019]
On the other hand, the unit holder 30 for mounting the flame detection unit 10 having the above-described structure on the upper surface thereof is shown in FIG. 5 as an external perspective view, and as shown in FIG. A front end holding portion (receiving portion) 31 into which the front end portion of the flame detection unit 10 is fitted is provided on the mounting surface side. The shutter 41 described above is selectively positioned inside the tip holding portion 31. In addition, an arc-shaped holding frame 32 that holds the peripheral wall of the flame detection unit 10 is provided at a substantially central portion of the unit holder 30, and a rear end portion of the unit holder 30 is opposed to the tip holding portion 31. A pair of press contact terminals 33, 33 are attached.
[0020]
These pressure contact terminals 33 and 33 are respectively mounted in recesses defined by a wall portion 34 provided at the center thereof, and in particular, a pair of external connections provided in steps in the flame detection unit 10. Corresponding to the terminals 4, 4, the distance from the receiving portion (tip holding portion) 31 is different. That is, these press contact terminals 33 and 33 are also provided with a step in the axial direction of the flame detection unit 10 attached to the unit holder 30.
[0021]
The wall portion 34 is formed with a guide groove 35 made of a slit having a predetermined width into which the partition wall portion 7 of the flame detection unit 10 described above is fitted. The guide groove 35 has a slit width corresponding to the thickness of the partition wall 7 and plays a role of preventing the thick portion 7a from entering. The guide groove 35 has a front end portion fitted into the front end holding portion (receiving portion) 31, and the flame detection unit 10 stands the partition wall portion 7 in the vertical direction, and further raises the thick portion 7a on the upper side. Thus, the partition wall 7 is fitted only when it is mounted from the thin side.
[0022]
Thus, according to the unit holder 30 having such a structure and the flame detection unit 10 having the above-described structure, the mounting positions of the external connection terminals 4 and 4 and the pressure contact terminals 33 and 33 have steps, respectively. The flame detection unit 30 cannot be mounted on the unit holder 30 unless the direction of the steps is matched. At the same time, unless the thick portion 7 a provided on the partition wall 7 is in the upper side, the partition wall portion 7 is not fitted into the guide groove 35, so that the flame detection unit 10 can be mounted on the unit holder 30. I can't do it. Only when these mounting conditions are satisfied, the flame detection unit 10 is completely mounted on the unit holder 30, and at the same time, the press contact terminals 33, 33 are connected to the pair of external connection terminals 4, 4 of the flame detection unit. Each is in pressure contact.
[0023]
Therefore, with such a structure, the flame detection unit 10 can be mounted on the unit holder 30 only when the flame detection unit 10 is correctly oriented around the axis. The unit holders 30 can be mounted together. Therefore, there is no problem of reverse connection of the external connection terminals 4 and 4. In particular, when the direction around the axis of the flame detection unit 10 is reversed, the direction of the steps of the external connection terminals 4 and 4 and the direction of the steps of the press contact terminals 33 and 33 are reversed. Accordingly, in combination with the above-described fitting preventing action between the partition wall portion 7 and the guide groove 35, it is possible to prevent the flame detection unit 10 from being erroneously attached to the unit holder 30.
[0024]
In addition, you may make it provide the protrusion 32a fitted to the groove-shaped notch 8b provided in the flange 8 of the flame | frame detection unit 10 in the holding frame 32 mentioned above. In this manner, the mounting direction of the flame detection unit 10 can be determined by the protrusion 32a and the notch portion 8b, so that the step structure of the external connection terminals 4 and 4 described above, Similar to the deformed structure, it is possible to prevent the flame detection unit 10 from being attached in the reverse direction.
[0025]
The present invention is not limited to the embodiment described above. For example, it is of course possible to configure the flame detection unit 10 by adopting only one of the step structure of the external connection terminals 4 and 4 and the deformed structure of the partition wall 7 described above. Further, according to the flame detection unit 10 having the above-described structure, even if the flame detection unit 10 is used alone without being attached to the unit holder 30, the external connection terminals 4 and 4 having a step structure can be used. Since the polarity can be easily grasped, it is effective in preventing reverse connection. Although an apparatus using a UV tube has been illustrated here, the same can be applied to a case where a semiconductor optical sensor is used. In addition, the present invention can be variously modified and implemented without departing from the scope of the invention.
[0026]
【The invention's effect】
As described above, according to the present invention, a deformed portion is provided on one side of the plate-like partition plate separating the pair of external connection terminals provided at the rear end portion of the flame detection unit , and the unit holder since a structure that prohibits the fitting to the provided guide grooves, to prevent erroneous connection of the connection terminals, it is practically tremendous effects such a flame detection unit can be surely mounted on the unit holder Played.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view showing a schematic overall structure of a flame detection apparatus according to an embodiment of the present invention.
2 is a partial cross-sectional configuration diagram showing an assembly structure of the flame detection device shown in FIG. 1;
FIG. 3 is an exploded view showing a schematic configuration of a flame detection unit.
FIG. 4 is a diagram for explaining the external shape of a flame detection unit and its characteristic points.
FIG. 5 is a diagram showing a schematic external shape of a unit holder to which the flame detection unit shown in FIG. 4 is attached.
6 is a schematic plan configuration diagram of the flame detection unit shown in FIG. 5. FIG.
[Explanation of symbols]
2 Holding body 3 Cylindrical casing 4, 4 External connection terminal 7 Bulkhead part 7a Thick part (deformed part)
8 Flange 8a Cut-off part (D cut surface)
8b Notch portion 10 Flame detection unit 30 Unit holder 31 Receiving portion (tip holding portion)
32 Holding frame 32a Protrusions 33, 33 Press contact terminal 34 Wall 35 Guide groove

Claims (3)

An ultraviolet ray detection discharge tube is built in a casing formed of a cylindrical body having a light receiving window at the front end portion, and a pair of external connection terminals connected to the ultraviolet ray detection discharge tube are provided at the rear end portion of the casing. Flame detection units arranged symmetrically around the axis of
A receiving portion into which the tip of the flame detection unit is fitted, and a pressure contact with the external connection terminal of the flame detection unit, which is provided opposite to the receiving portion and fitted with the tip fitted into the receiving portion. A unit holder provided with a pair of press contact terminals ,
The flame detection unit includes a pair of external connection terminals spatially compartment to plate-like partition wall which protrudes from the rear end of the casing, provided on one side portion of the partition wall With a deformed part,
The unit holder allows the partition part of the flame detection unit, which is mounted with a tip part fitted into the receiving part, to be fitted only from a side opposite to the side where the deformed part is provided. A flame detection device comprising a guide groove. The partition portion divides the rear end portion of the casing as a semicircular region in which the pair of external connection terminals are respectively provided,
The flame detection device according to claim 1 , wherein the deformed portion is provided as a thick portion. 2. The flame detection device according to claim 1 , wherein the unit holder includes an arc-shaped holding frame that holds a peripheral wall of the flame detection unit that is mounted with a tip end fitted into the receiving portion.

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