WO1997021958A1

WO1997021958A1 - Return type spray nozzle

Info

Publication number: WO1997021958A1
Application number: PCT/JP1996/003557
Authority: WO
Inventors: Yasuo Matake; Hideaki Koga
Original assignee: Matake Sangyo Co. Ltd.
Priority date: 1995-12-08
Filing date: 1996-12-04
Publication date: 1997-06-19
Also published as: EP0809069A4; EP0809069A1

Abstract

In a return type spray nozzle, a small hole (90) for return is provided in a distributor (60) so as to be eccentric relative to the central axis (X) of a small hole (51) for spray, a liquid fuel supplied to a spray stand-by chamber (70) is jetted from the small spraying hole (51) of a spray nozzle body (50), and a part of the liquid fuel is returned through the small hole (90) for return. The small hole (90) for return is defined as a through gap formed in a boundary region between a central through hole (63), which is formed near the center of a tip end of the distributor (60) so as to be coaxial with the central axis (X) of the small hole (51) for spray, and a core body (80), which is different in cross-sectional shape from and fitted into the central through hole (63), by the central through hole (63) and the core body (80).

Description

Description Return type spray nozzle Technical field

The present invention relates to a return type spray nozzle, and more particularly, to a liquid fuel combustor such as a household water heater or a heater which requires a relatively small combustion capacity, is fine, accurate, and requires a large turndown ratio. The present invention relates to a return type spray nozzle that can be used. Background art

The return type spray nozzle, as shown in the schematic diagram of Fig. 11, ejects the liquid fuel sent from tank 1 through pump 2 to supply type spray nozzle 4 to recirculation type spray nozzle 4, and burns. The nozzle is provided to return to the return path 5 without spraying a part of the supplied liquid fuel. The liquid fuel returned to the return path 5 is returned to the tank 1 or the like as shown in FIG. 11, or is circulated again on the way to the inlet side of the pump 2 in the supply path 3. The return amount is adjusted by the return amount control valve 6.

The conventional return type spray nozzle has a spray nozzle main body 10 and a distributor 20 fitted in an inner hole 11 thereof, as shown in a vertical sectional view of FIG. I have. The spray nozzle main body 10 is provided with a spray pore 12 at the center of the tip. Further, the distributor 20 is formed with a return hole 21 penetrating through the center of the flat portion 25 at the tip and a shoulder 22 contacting the inner hole 11 of the spray nozzle body 10. A plurality of fuel supply slit grooves 23 are provided. The liquid fuel sent from the pump 2 passes from the inner hole 11 of the spray nozzle body 10 through the fuel supply slit groove 23 and the spray standby chamber 3 After entering 0, it is ejected from the spray holes 12. A part is returned from the spray standby chamber 30 through the return pore 21.

However, in the conventional return type spray nozzle shown in FIG. 12, the position of the return hole 21 of the distributor 20 and the position of the spray hole 12 of the spray nozzle body 10 are coaxial. And the center of the swirling vortex generated by the momentum of the liquid fuel introduced into the spray standby chamber 30 through the plurality of slit grooves 23 enters the re-opening pore 21. Therefore, when the return flow rate of the liquid fuel increases and the spray amount decreases, air from the outside passes through the center of the swirling vortex and enters the return pore 21 together with the liquid fuel. There was a problem of mixing.

The invention of Japanese Patent Application Laid-Open No. 2-217770 is provided as a re-spray type spray nozzle which solves the above problem. The configuration of the present invention is shown in FIGS. 13 and 14. FIG. 13 is a longitudinal sectional configuration view of a main part of the nozzle, and FIG. 14 is a plan view of the distributor 20. In the present invention, the center is located near the center of the flat portion 25 at the tip of the distributor 20 with respect to the central axis X of the spraying pore 12 provided at the center of the tip of the spray nozzle body 10. A return hole 24 is provided at a position eccentric from the axis X to penetrate.

By providing the return pores 24 so as to be off the center axis X of the spray pores 12, the return pores 24 pass through the center of the swirling vortex of the liquid fuel in the spray standby chamber 30 from the spray pores 12. It is possible to prevent the external air that has entered by mixing with the fuel into the pores 24 for return.

A plurality of (two in the figure) pores 24 are provided at symmetrical positions around the central axis X. In FIGS. 13 and 14, members, parts and elements similar to those described in FIG. 12 are denoted by the same reference numerals.

However, the return spray nozzle shown in Figs. 13 and 14 above In the case of using a large size combustor, since the overall spray amount is large, the diameters of the spraying holes 12 and the return holes 24 become relatively large. The drilling of holes 12 and 24 does not pose a significant problem, but if a smaller-capacity combustor is to be used for home use, etc. It becomes necessary to make the hole diameter of 4 smaller. In particular, when the return holes 24 are configured to be eccentric from the center axis X, it is necessary to provide a plurality of return holes 24 symmetrically in consideration of balance. In this case, it is necessary to make the diameters of the individual return pores 24 considerably small. For example, the diameter of the circular flat portion 25 at the tip of the distributor 20 is about 3 to 4 occluded or more, and the return hole 24 having a diameter of about 1 to 1.5 hidden hole is formed in the flat portion 25. In this case, it is also possible to directly perforate the return pores 24 in the flat portion 25.The diameter of the flat portion 25 at the tip of the distributor 20 is further reduced, Then, when it is desired to form a return pore 24 having a smaller pore diameter in the plane portion 25, for example, a return pore 24 having a pore diameter of about 0.3 to 0.4 hidden, It was difficult to directly drill the small-diameter hole 24 for cleaning, and even when drilling was possible, the cost of the drilling equipment was extremely high.

Therefore, the present invention solves the above-mentioned conventional problems, and a small return pore can be obtained reliably, easily and at low cost at a position eccentric with respect to the center axis of the spray pore. The purpose of the present invention is to provide a return spray nozzle capable of preventing external air from being caught in the return pores and obtaining a delicate, accurate and large turndown ratio in small capacity combustion. I do. Disclosure of the invention In order to achieve the above object, a return type spray nozzle according to the present invention has a spray nozzle main body and a distributor fitted in an inner hole of the spray nozzle main body, and the spray nozzle main body has A spraying hole is provided in the center of the distributor, and the distributor is provided with a return hole near the center of the tip of the distributor at a position eccentric from the center axis of the spraying hole and a shoulder of the distributor. A slit groove for supplying fuel for supplying the liquid fuel sent through the inner hole of the spray nozzle main body to the spray standby chamber in front of the distributor tip is provided on the outer side, and is supplied to the spray standby chamber. Return spray from the spray waiting chamber through the spray hole, and return from the spray waiting chamber through the return hole without spraying part of the liquid fuel. A nozzle, the distributor The return hole has a central through-hole formed near the center of the tip of the distributor and coaxial with the central axis of the atomizing hole, and has a cross-sectional shape that is inconsistent with the central through-hole. The first feature is that the core to be fitted is configured as a through gap generated in a boundary region between the center through hole and the core fitted to the center through hole.

In addition, in addition to the first feature, the return spray nozzle of the present invention further comprises a core having a concave streak formed on the outer surface, which is fitted and fixed in the center through-hole, so that the core and the center through-hole can be connected to each other. A second feature is that the return fine pores formed by the concave streaks are formed in the boundary area as through spaces.

Further, in addition to the first feature, the return spray nozzle of the present invention has a structure in which the core is fitted into and fixed to the center through-hole having a concave streak on the inner surface, so that the core and the center through-hole can be connected to each other. A third feature is that a return pore formed by the concave stripe is formed as a through space in the boundary area.

In addition, in the return spray nozzle of the present invention, in addition to the features described in any one of the first to third aspects, a plurality of return pores are provided symmetrically around the central axis. This is the fourth feature. Further, in addition to the first feature, the return type spray nozzle of the present invention further comprises a similar core having a smaller diameter than the central through-hole, which is fitted and fixed in the central through-hole, so that the core and the central through-hole can be fixed. The fifth feature is that a ring-shaped pore for the ring is formed as a through gap in the boundary area with the hole.

In the first feature, the central through-hole formed coaxially with the center axis of the spray hole near the center of the tip of the distributor, and fitted with a cross-sectional shape inconsistent with the central through-hole. The through hole formed in the boundary area due to the different cross-sectional shapes of the core is used as the return pore, so that the return pore having a small pore diameter can be easily formed in the center axis. It can be configured with eccentricity. Since the diameters of the center through-hole and the core itself can be relatively large, drilling is easy. In addition, by making the cross-sectional shapes of the center through hole and the core body inconsistent, it is necessary to add or cut axially convex and concave stripes on the inner surface of the center through hole and the outer surface of the core body. This can be easily performed by drawing, drawing, or coining. Therefore, compared with a case where a small hole is directly drilled in the distributor, the return hole can be formed much easier and at low cost.

The number of the return pores may be plural, such as two, three, or four, but may be one. When a plurality of holes are formed, it is preferable to provide them symmetrically around the central axis in order to balance the suction of the return flow, but it is not always necessary for each return hole to be at a symmetric position.

By providing the return pore eccentrically from the central axis, it is possible to prevent the air that has entered from the spray pore through the center of the vortex in the spray standby chamber from entering the return pore.

In addition, by utilizing the gap between the center through hole and the core body fitted therein, a return pore having a sufficiently small hole diameter can be obtained reliably, easily, and easily. As a result, it is possible to more reliably prevent air from entering the return pores, and it is easy to form a plurality of return pores. Since it can be increased, it is easy to increase the turndown ratio.

For fitting the center through hole and the core body, for example, cold fitting, shrink fitting, ultrasonic fitting, and other well-known techniques can be used.

In the above second feature, the concave streak on the outer surface of the core body can be formed by pulling the portion, shaving, or coining. In addition, the core having a concave streak on the outer surface is fitted and fixed in the center through-hole, so that the return pore by the concave streak is formed in the boundary area between the core and the center through-hole. As a result, it is possible to obtain a return hole with a sufficiently small diameter eccentric from the central axis, to reliably prevent air from entering the return hole and to achieve a small capacity. It is possible to reliably adjust the capacity in combustion.

In the third feature, the concave streak on the inner surface of the center through hole can be configured in the same manner as in the case of the core. Further, in addition to the operation and effect of the first feature, the core is fitted into and fixed to the center through hole having the recess formed on the inner surface, so that the recess is formed in the boundary area between the core and the center through hole. Because the return pores are formed as through gaps, the return pores with sufficiently small diameter can be obtained eccentrically from the central axis, ensuring that air can enter the return pores. Prevention and capacity adjustment in small capacity combustion can be performed reliably.

According to the fourth feature, in addition to the operation and effect of any of the first to third features, since a plurality of return pores are provided symmetrically around the central axis, Liquid returned from the standby chamber to the return pore The body fuel is balanced, so that there is no excess or deficiency of the liquid fuel in the spray standby chamber, and stable spray can be performed from the spray standby chamber.

According to the fifth feature, in addition to the action and effect of the first feature, a return pore having a small diameter can be obtained in a ring shape at a position eccentric from the central axis, and air is returned. In addition, it is possible to reliably prevent intrusion into the pores for use, and to surely adjust the capacity in small capacity combustion. BRIEF DESCRIPTION OF THE FIGURES

FIGS. 1, 2, 3, and 4 show a first embodiment of the present invention, FIG. 1 is a partial cross-sectional view schematically showing the entirety of a return type spray nozzle, and FIG. FIG. 3 is a longitudinal sectional configuration view of a main part of the turn type spray nozzle, FIG. 3 is a plan view of a main part of the distributor, and FIG. 4 is a perspective view of a core.

5 and 6 show a second embodiment of the present invention. FIG. 5 is a plan view of a main part of a distributor of a return type spray nozzle, and FIG. 6 is a perspective view of a core. 7 and 8 show a third embodiment of the present invention. FIG. 7 is a longitudinal sectional view of a main part of the distributor of the return type spray nozzle, and FIG. 8 is a plan view of a main part of the distributor. FIG.

9 and 10 show a fourth embodiment of the present invention. FIG. 9 is a vertical sectional view of a main part of a distributor of a return type spray nozzle, and FIG. 10 is a return type spray nozzle. It is a top view of the distributor of a fog nozzle.

Fig. 11 and Fig. 12 show a conventional example. Fig. 11 is an overall schematic diagram of a return spray nozzle. Fig. 12 is a longitudinal sectional view of a main part of a return spray nozzle. FIG.

Fig. 13 and Fig. 14 show other conventional examples, Fig. 13 is a vertical cross-sectional view of the main part of a return spray nozzle, and Fig. 14 is a distributor of a return spray nozzle. FIG. BEST MODE FOR CARRYING OUT THE INVENTION

In FIG. 1, a supply path 3 for liquid fuel such as petroleum and a return path 5 are connected to a return spray nozzle 4 in the same manner as in FIG. At the head of the return type spray nozzle 4, a spray nozzle main body 50 is provided, and a distributor 60 is provided in the spray nozzle main body 50.

The spray nozzle main body 50 is detachably screwed to the distal end of the outer cylinder case 41 of the return spray nozzle 4. The distributor 60 is fitted and fixed to the distal end of the inner cylinder 42 of the return spray nozzle 4. The inner cylinder 42 and the outer cylinder case 41 are removably screwed and fixed concentrically. 4 3 is the evening. The oil that has entered the return type spray nozzle 4 from the tank 1 (not shown) (see Fig. 11) through the supply path 3 is sent forward between the outer cylinder case 4 1 and the inner cylinder 4 2, and the filter 4 After the contaminants and the like are removed in 3, the vehicle further proceeds forward, passes through the inner hole of the spray nozzle body 50, passes between the spray nozzle body 50 and the distributor 60, and passes through the inside of the distributor 60. It is supplied to the spray standby room 70 ahead. The petroleum supplied to the spray standby chamber 70 is jetted from the spray nozzle 51 of the spray nozzle main body 50 and is provided for combustion. Some of the oil is returned from the spray standby chamber 70 to the inner cylinder 42 through a return hole 90 of the distributor 60 described later, and further returned to the return path 5. The amount of oil to be returned is adjusted by the return amount control valve 6. The adjustment by the return amount control valve 6 is automatically adjusted by a controller (not shown) according to the required amount of combustion heat.

This will be described in more detail with reference to FIGS. 2, 3, and 4. FIG. At the center of the tip of the spray nozzle body 50, a spray hole 51 is provided. The central axis X of the spray hole 51 is also the center axis of the spray nozzle body 50, and It is also the central axis of the turn type spray nozzle 4 itself. The distributor 60 is fitted into the inner hole of the spray nozzle body 50 by means of a hinge, but the distributor 60 abuts against a circular inner hole 52 near the tip of the spray nozzle body 50. A plurality of fuel supply slit grooves 62 are provided in the shoulder outer portion 61 of the container 60. In this example, four fuel supply slit grooves 62 are provided. However, three or six fuel supply slit grooves may be provided, and the number of fuel supply slit grooves is not limited. It is preferable to provide a The oil is supplied to the spray standby chamber 70 in front of the tip of the distributor 60 through the fuel supply slit groove 62.

The spray standby chamber 70 is provided near the tip of the circular inner hole 52 of the spray nozzle main body 50, a flat portion 6 formed on the wall of the conical inner hole 52 and the tip of the distributor 60. 5 and the center axis X is the center of the space.

Near the center of the tip of the distributor 60, a central through hole 63 is formed coaxially with the central axis X. The central through hole 63 is continuous with the enlarged through hole 64 of the distributor 60, and the enlarged through hole 64 is connected to the inner cylinder 42 (see FIG. 1).

A core body 80 is fitted in the center through hole 63 of the distributor 60. In the embodiment shown in FIGS. 1 to 4, the core body 80 is a rod-like body having a plurality of concave streaks 81 formed on the outer surface thereof in the axial direction. By fitting this core body 80 into the center through hole 63, the concave streak 81 and the inner surface of the center through hole 63 are formed in the boundary area between the closely adhered center through hole 63 and the core body 80. A through gap surrounded by is defined, and this through gap forms a return hole 90. That is, since the cross-sectional shape of the core body 80 fitted into the central through-hole 63 does not match at the concave streak 81, return pores 90 can be formed, and further, the return pores 90. Is configured at a position eccentric from the central axis X. The core body 80 is actually slightly larger in size than the center through-hole 63, and the core body 80 and the center through-hole 63 are subjected to ultrasonic vibration or shrink-fit or cold-fit. By doing so, it can be fitted and fixed in close contact. Further, the concave streak 81 formed in the outer surface of the core body 80 in the axial direction can be configured by pulling the outer surface in the axial direction. It can also be cut. Further, it can be formed by press working such as coining. Since only a concave streak is formed on the outer side surface, a concave streak having a size sufficiently smaller than that of forming a hole can be formed very simply, easily, and reliably.

By arranging a plurality of the concave streaks 81 at symmetric positions in the circumferential direction, it is possible to obtain an arrangement balance of the obtained return pores 90. By keeping the arrangement balance, it is possible to perform a return while balancing the presence of oil in the spray standby chamber 70. In addition, the diameter of each of the return pores 90 is small, and the overall open area of the return pores 90 is sufficiently large, so that the turndown ratio in combustion control is sufficiently large. can do.

5 and 6 show a second embodiment of the present invention. FIG. 5 is a plan view of a main part of the distributor, and FIG. 6 is a perspective view of a core.

In this example, a rod-shaped body having a triangular horizontal cross section is used as the core body 80 fitted into the center through hole 63 of the distributor 60. By making this core body 80 have a substantially triangular horizontal cross section, the triangular prism-shaped core body 80 is fitted into the circular center through hole 63 to thereby make the center through hole adhered closely. In the boundary area between 63 and the core body 80, a pore 9 () is formed as a through gap as a through gap. In this embodiment, each side of the triangular prism is a concave streak 81. Other configurations and operations are the same as those of the first embodiment. FIG. 7 and FIG. 8 show a third embodiment of the present invention. Figure 7 shows the main components of the distributor. FIG. 8 is a plan view of a main part of the distributor.

In the present embodiment, a plurality of return pores 90 are eccentric around the central axis X by forming a concave streak 63 a on the side of the central through hole 63 of the distributor 60. It consists of. That is, a plurality of concave stripes 63 a are formed on the inner side surface of the center through hole 63, and the core 80 is fitted and fixed in the center through hole 63, so that the closely contacted center through hole 63 is formed. A through gap surrounded by the concave streak 63 a and the outer surface of the core body 80 is formed in a boundary region between the core 3 and the core body 80, and the return gap 90 is formed by the through gap. Make up.

The core body 80 is actually slightly larger in size than the center through-hole 63, and the core body 80 and the center through-hole 63 are subjected to ultrasonic vibration or shrink-fit or cold-fit. By doing so, it can be fitted and fixed in close contact. In addition, the concave streak 63 a formed in the inner surface of the center through hole 63 in the axial direction can be configured by pulling the inner surface in the axial direction. It can also be cut. Further, it can be formed by press working such as coining. Since only a concave streak is formed on the inner surface, a concave streak having a size sufficiently smaller than that of forming a hole can be formed very simply, easily, and reliably.

By arranging a plurality of the concave streaks 63 a at symmetrical positions in the circumferential direction, it is possible to obtain an arrangement balance of the obtained return pores 90. By balancing the arrangement, it is possible to carry out the reinfestation while balancing the presence of oil in the spray standby room 70.

This embodiment basically has the same operation and effect as the case where the concave streak 81 is provided on the core 80 side.

In the first to third embodiments, if the number of the concave stripes 63 a formed in the center through hole 63 and the number of the concave stripes 81 formed in the core body 80 are plural, The number is not particularly limited. The shape and size of the concave stripes 6 3 a and 81 are also special. However, the present invention is not limited to this.

Further, the length of the core body 80 is set to a length comparable to the length of the center through hole 63, but it is not necessary that the length is the same as that of the center through hole 63. It can be shorter or longer.

Further, in the above-described first to third embodiments, the central through-hole 63 and the core 80 are formed with the concave stripes 63 a and 81, so that the central through-holes closely fitted to each other are fitted. A through gap is formed in the boundary area between 63 and the core body 80, thereby forming a pore 90 for the cleaning. It is not necessary that the ridges 63a, 81 be formed. In other words, if a through gap is formed in the boundary area between the center through hole 63 and the core body 80 fitted in close contact with the core body 80 by disagreement of the cross-sectional shape of the core body 80 and the center through hole 63, then the penetration Since the gaps can be the return pores 90, irregularities and any other shape changes between each other can be used instead of the concave streaks 63a and 81. Further, a specific processing method for forming the shape mismatch is not limited to the method described above.

FIG. 9 and FIG. 10 show a fourth embodiment of the present invention. FIG. 9 is a longitudinal sectional view of a main part of the distributor, and FIG. 10 is a plan view of the distributor.

In the above-described embodiment, the core body 80 is fitted into the central through-hole 63 of the distributor 60 in close contact with the portion except for the concave streaks 63 a and 81, whereas this embodiment Then, a similar core body 80 having a smaller diameter than the central through hole 63 is fitted into and fixed to the central through hole 63 of the distributor 60, so that the core body 80 and the central through hole A single ring-shaped through gap is formed continuously at the boundary area with 3, and this is defined as a return pore 90.

The fixing method of the core body 80 is as follows. The length of the core body 80 is made longer than the center through hole 63, and the rear part of the core body 80 protruding from the center through hole 63 to the enlarged through hole 64. The fixture 100 should not interfere with the flow of return flow. Then, it is fixed to the inner wall of the enlarged through hole 64. The fixture 100 may be three projecting pieces integrally attached to the rear of the core body 80 at an angle of 120 degrees to each other. In this case, the core 80 to which the projecting piece as the fixing tool 100 is integrally attached is inserted from the side of the enlarged through hole 64 and fixed. The fixing tool 100 may be integrally fixed to the enlarged through hole 64 side. In this case, three support members extending in the center direction from the positions of 120 degrees on the inner wall of the enlarged through hole 64 are used as fixtures, and the support members support the core body 80 from the surroundings. I do. Further, the fixing tool 100 may be detachable from any of the core body 80 and the enlarged through hole 64. In this case, the core body 80 may be fitted into the fixture 100 and fixed, and then fitted into the enlarged through hole 64, or the fixture 100 may be fitted into the enlarged through hole 64 first. After that, the core body 80 may be fitted.

In addition, without providing the fixing tool 100 as shown in FIG. 9 or in addition to the fixing tool 100, the periphery of the outer surface of the core body 80 at a portion to be fitted into the center through hole 63. Small protrusions are provided on the surface in a well-balanced manner, and when the core body 80 is fitted into the center through-hole 63, the protrusion comes into contact with the inner wall of the center through-hole 63 so that the ring-shaped through gap is formed. May be secured.

The center through-hole 63 described in the above-described embodiment is preferably a hole having a circular cross section. However, the center through hole 63 is not necessarily required to have a circular shape. There may be. Similarly, it is preferable that the core body 80 has a circular cross section and the cross section is deformed by concave means 81 or other means.However, basically, the core body 80 has a polygonal cross section other than the circular cross section. Deformation means may be added to this.

The length of the core body 80 is not particularly limited.

The diameter of the spraying pore 51 is, for example, about 1 or less for small capacity. It can be changed according to the target combustion capacity, and is not particularly limited. ₍ The diameter of the return pore 90 is 1 mm or less for small capacity, for example, about 0.3 to 0.4 country. Although it can be easily configured in the present invention, the diameter of the return pores 90 can also be a diameter according to the ability, and is not particularly limited.

In addition, it is, of course, essential that the return pores 90 be configured eccentrically from the central axis X, but the configuration is not particularly limited in terms of other arrangements, shapes, and the like. Industrial applicability

According to the return type spray nozzle according to claim 1, the return pores of the distributor are arranged near the center of the tip end of the distributor. A central through hole formed coaxially with the central axis of the center through hole, and a core body fitted with an inconsistent cross-sectional shape with respect to the central through hole, the boundary area between the central through hole and the core body fitted therein. Because it is configured as a through gap that occurs,

The return pore having a sufficiently small diameter required for low-capacity combustion can be easily and eccentrically formed from the central axis.

In addition, since the diameter of the center through hole and the diameter of the core itself can be relatively large, drilling is easy.

In addition, by making the cross-sectional shapes of the center through hole and the core body inconsistent, it is necessary to add or machine axial convex and concave stripes on the inner surface of the center through hole and the outer surface of the core body. It can be easily done by processing, pulling, or coining. Therefore, compared with the case where small holes are directly drilled in the distributor, the return holes can be formed much easier and at low cost. Also, it is easy to form a plurality of return pores, and the return amount can be easily increased accordingly, so that the turndown ratio can be easily increased.

Of course, by providing the return hole eccentrically from the central axis, it is possible to prevent air that enters from the spray hole through the center of the vortex in the spray standby chamber from trying to enter the return hole. . In addition, by utilizing the gap between the center through hole and the core body fitted therein, a return hole having a sufficiently small hole diameter can be obtained reliably, easily, and easily. Intrusion into the pores can be more reliably prevented.

According to the return type spray nozzle of the second aspect, in addition to the effect of the configuration of the first aspect, a core body having a concave streak on the outer surface is fitted and fixed in the center through hole. However, since the return hole formed by the above-mentioned concave streak is formed as a through gap in the boundary area between the core body and the center through hole, it is necessary to obtain a sufficiently small return hole eccentric from the center axis. As a result, it is possible to reliably prevent air from entering the return pores, and it is possible to reliably perform capacity adjustment in small capacity combustion.

According to the return spray nozzle of the third aspect, in addition to the effect of the configuration of the first aspect, the core body is fitted and fixed in the center through-hole having a concave streak on the inner surface. As a result, the return hole formed by the above-mentioned concave streak is formed as a through gap in the boundary area between the core body and the center through hole, so that the return hole having a sufficiently small hole diameter is formed in the center axis. Thus, it is possible to reliably prevent the air from entering the return pores and adjust the capacity in small capacity combustion.

According to the return type spray nozzle according to claim 4, in addition to the effect of the configuration according to any one of claims 1 to 3, a plurality of return pores are provided symmetrically around the central axis. From the spray standby room The liquid fuel returned to the spray pores is balanced, so that there is no excessive or insufficient location of the liquid fuel in the spray waiting room, and stable spraying can be performed from the spray waiting room.

According to the return type spray nozzle of the fifth aspect, in addition to the effect of the configuration of the first aspect, a return pore having a small diameter is formed in a ring shape at a position eccentric from the central axis. As a result, it is possible to reliably prevent air from entering the cleaning pores, and to reliably perform capacity adjustment in small capacity combustion.

Claims

Claims: A spray nozzle body (50) having a spray nozzle body (50) and a distributor (60) fitted in an inner hole of the spray nozzle body (50); The dispenser (60) is provided with a spray pore (51) at the center of the tip thereof, and the spray pore (51) is provided near the center of the distributor (60) tip. ), A return hole (90) is provided at a position eccentric from the central axis (X), and an inner hole of the spray nozzle body (50) is provided at a shoulder outer portion (61) of the distributor (60). The fuel supply slit groove (62) for supplying the liquid fuel sent through the inside to the spray standby chamber (70) in front of the tip of the distributor (60) is provided, and the spray standby chamber (70) is provided. ) Is sprayed from the spray standby chamber (70) through the spray pores (51), and the liquid fuel is sprayed without causing some of the liquid fuel to be sprayed. A return type spray nozzle (4) that returns from the standby chamber (70) through the return hole (90), and includes a return hole (90) of the distributor (60). ) Is a central through-hole (63) formed near the center of the tip of the distributor (60), coaxially with the central axis (X) of the spray pore (51), The core body (80) fitted with an inconsistent cross-sectional shape with respect to the hole (63) causes a boundary area between the central through hole (63) and the core body (80) fitted therein. A return type spray nozzle characterized by being configured as a through gap.

2. The core (80) having the concave strip (81) formed on the outer surface is fitted and fixed in the center through-hole (63), so that the core (80) and the center through-hole (63) are fixed. The return type spray nozzle according to claim 1, wherein a return pore (90) formed by the concave streak (81) is formed as a through gap in a boundary area between and.

3. The core body (80) is fitted and fixed in the center through hole (63) having a concave streak (63a) on the inner surface, so that the core body (80) and the center through hole (63) are fixed. ) 2. The return spray nozzle according to claim 1, wherein a return pore (90) formed by the concave streak (63 a) is formed as a penetrating gap in a boundary area between the return spray nozzle and the nozzle.

4. The return spray nozzle according to any one of claims 1 to 3, wherein a plurality of return pores (90) are provided symmetrically around the central axis (X).

5. A core (80) having a smaller diameter than the center through-hole (63) is fitted and fixed in the center through-hole (63), so that the core (80) and the center through-hole (80) are fixed. 3. The return spray nozzle according to claim 1, wherein a ring-shaped cleaning pore (90) is formed as a through gap in a boundary region with the gap (63).