JP7542434B2 - Spout head of backpack-type power sprayer - Google Patents

Description

The present invention relates to a nozzle for a backpack-type power sprayer.

A backpack-type power sprayer described in the following Patent Document 1 is known. In this backpack-type power sprayer, an operator drives the fan while carrying the work machine body, which is equipped with a fan (air blower) and a chemical tank, on his back, and sends air from the fan through an air pipe (corrugated pipe, air pipe, etc.) to a nozzle at the end of the air pipe. At the same time, chemical liquid from the chemical tank is supplied through a liquid supply hose (liquid supply pipe) to a nozzle (mist nozzle) installed in the nozzle at the end of the air pipe, so that the operator can spray the chemical liquid from the nozzle in a mist from the nozzle in the desired direction while holding the air pipe.

Patent 5235071

If the downstream side of the air duct is lifted and the chemical solution is sprayed diagonally upward or directly upward (hereinafter simply referred to as upward), the chemical solution from the nozzle accumulates as droplets on the tip part downstream of the nozzle of the nozzle head, particularly on the inner peripheral surface of the trumpet part of the nozzle head tip in Patent Document 1, and there is a risk that the accumulated droplets will drip off after spraying. This is particularly noticeable when the nozzle is installed in the air duct upstream of the nozzle head, for example in a direct injection pipe (air supply pipe), away from the nozzle head.

The present invention was made to solve these problems, and provides a backpack-type power sprayer nozzle that can easily atomize the water droplets that have accumulated on the inner peripheral surface of the tip of the nozzle, resulting in more suitable spraying.

The nozzle (10) of the backpack-type power sprayer (100) according to the present invention is configured such that the operator carries on his back the work machine body (1) equipped with the drive source (4), fan, fan case (6), and chemical tank (3), and drives the fan by driving the drive source (4), sends the air from the fan in the fan case (6) to the tip of the air pipe (2) through the air pipe (2), and supplies the chemical liquid from the chemical tank (3) to the nozzle (11) installed in the air pipe (2) through the liquid supply hose (14), and sprays the chemical liquid discharged from the nozzle (11) in a mist form from the tip of the air pipe (2). The nozzle head (10) is characterized in that it has an annular ring portion (19) attached to the inner peripheral surface downstream of the nozzle (11), and on the outer peripheral surface (24) of the ring portion (19), a plurality of outer grooves (25) are formed along the circumferential direction, which extend in the axial direction of the nozzle head (10) and form an outer flow path (36) between the inner peripheral surface of the nozzle head (10), and on the bottom surface (26) of the ring portion (19), a plurality of bottom grooves (30) are formed along the circumferential direction, which communicate with the upstream end of the outer groove (25), face the axial center of the nozzle head (10), and communicate with the inner peripheral surface (29) of the ring portion (19) and open inward.

According to the nozzle head (10) of such a backpack-type power sprayer (100), an outer flow path (36) is formed between the outer groove (25) that is provided on the outer peripheral surface (24) of the ring portion (19) and extends in the axial direction and the inner peripheral surface of the nozzle head (10). This outer flow path (36) and the bottom groove (30) that is provided on the bottom surface (26) of the ring portion (19) and communicates with the outer groove (25), extends toward the axis of the nozzle head (10), communicates with the inner peripheral surface (29) of the ring portion (19), and opens inward, are under negative pressure, so that the water droplets that have accumulated on the inner peripheral surface of the tip portion (17) of the nozzle head (10) are pulled by the air blown from the fan passing through the nozzle head (10) and flow upstream through the outer flow path (36), are sucked up from the open end through the bottom groove (30), and are easily atomized by the air blown from the fan. This allows for more optimal spraying.

Here, the bottom surface (26) of the ring portion (19) has an inclined surface (28) that inclines from upstream to downstream toward the axis of the nozzle (10), and the bottom groove (30) is inclined to follow the inclined surface (28), so that water droplets are easily sucked up along the bottom groove (30), enabling more effective spraying.

In addition, a circular protrusion (23) is provided on the inner peripheral surface of the nozzle (10) to fit the bottom surface (26) of the ring portion (19) and to attach the ring portion (19), and an inner flow path (37) is preferably formed between the top surface of the protrusion (23) that faces the bottom surface (26) and the bottom groove (30). With this configuration, a tubular inner flow path (37) is formed instead of a groove, so that water droplets can be more effectively directed into the inner flow path (37).

In addition, an annular gap (S) is provided between the upstream end (27) on the outer periphery of the ring portion (19) and the outer periphery end (35) of the protruding portion (23) facing it. If the outer grooves (25) and bottom grooves (30) are connected to the gap (S), negative pressure is reliably applied evenly to each groove (25, 30) through the gap (S), allowing water droplets to flow more efficiently.

In addition, if there are more bottom grooves (30) than outer grooves (25), and a portion (31) of the bottom grooves (30) is linearly connected to the outer grooves (25) via a gap (S), and the remaining portion (32) of the bottom grooves (30) is connected only to the gap (S), negative pressure is reliably and evenly applied to each groove (25, 31, 32) through the gap (S), allowing the water droplets to flow more optimally, and water droplets are sucked up from more bottom grooves (30), resulting in more optimal spraying.

In this way, the present invention provides a backpack-type power sprayer nozzle that can easily atomize water droplets that have accumulated on the inner peripheral surface of the nozzle tip, allowing for more suitable spraying.

1 is a perspective view of a backpack-type power sprayer equipped with a nozzle according to an embodiment of the present invention, seen from the right rear and above. FIG. FIG. 2 is a perspective view of the nozzle in FIG. 1 as seen from the downstream side. FIG. 2 is a top view of the nozzle in FIG. 1 as seen from the downstream side. FIG. 2 is a bottom view of the nozzle in FIG. 1 as seen from the upstream side. FIG. 4 is a cross-sectional view taken along line V-V in FIG. FIG. 6 is a perspective view of the nozzle as viewed from the downstream side with the ring portion removed from FIG. 2 to FIG. 5. FIG. 7 is a perspective view of the nozzle shown in FIG. 6 as seen from the upstream side. FIG. 8 is a top view of the nozzle head shown in FIGS. 6 and 7 . FIG. 9 is a bottom view of the nozzle shown in FIG. 8 . FIG. 9 is a cross-sectional view taken along line X-X in FIG. 8 . 10 is a cross-sectional view taken along line XI-XI in FIG. 8 . FIG. 6 is a perspective view of the ring portion in FIGS. 2 to 5 as viewed from the downstream side. 13 is a perspective view of the ring portion shown in FIG. 12 as viewed from the upstream side. FIG. 14 is a side view of the ring portion shown in FIGS. 12 and 13 . FIG. 15 is a top view of the ring portion shown in FIG. 14 . FIG. 15 is a bottom view of the ring portion shown in FIG. 14 .

The following describes a preferred embodiment of the nozzle of a backpack power sprayer according to the present invention, with reference to the attached drawings. In the following description, terms that indicate directions such as up/down, front/back, left/right, etc., indicate directions based on the operator carrying the backpack power sprayer on his/her back, and the front of the operator is defined as "front."

Figure 1 is a perspective view of a backpack-type power sprayer equipped with a nozzle according to an embodiment of the present invention, seen from the right rear and above, Figures 2 to 5 are views showing the nozzle head in Figure 1, Figures 6 to 11 are views of the nozzle head with the ring portion removed, and Figures 12 to 16 are views showing the ring portion.

As shown in FIG. 1, the backpack-type power sprayer 100 is a device in which an operator wears the work machine body 1 on his/her back via a backpack strap, and sprays the chemical solution using an air duct 2 connected to the work machine body 1. Note that the backpack strap has been removed and is not shown here.

The working machine body 1 generally comprises a chemical tank 3 that stores the chemical liquid inside and forms the upper part of the working machine body 1 while also serving as the front backrest, an engine 4 that serves as a drive source forming the rear and lower part of the working machine body 1, a fan that is positioned below the chemical tank 3 and serves as an air blower that is driven to rotate by the engine 4, and a fan case 6 that houses the fan.

An air duct 2 is connected to the air outlet of the fan case 6 for sending the air from the fan to the tip side and spraying the medicinal liquid from the tip. The air duct 2 is equipped with a coiled tube 7 connected to the fan case 6, a direct injection tube (straight tube) 9 connected to the coiled tube 7 and extending straight, and a nozzle 10 connected to the direct injection tube 9.

A nozzle 11 is disposed upstream of the nozzle head 10. This nozzle 11 is connected to a liquid outlet 15 at the bottom of the liquid tank 3 via a liquid supply hose (liquid supply pipe) 14. In other words, the liquid in the liquid tank 3 is supplied to the nozzle 11 via the liquid supply hose 14. The nozzle 11 may be any known nozzle that is tubular and has an outlet facing forward, including the tubular nozzle of the prior art (Patent 5235071).

As shown in Figures 1, 2 and 5, the nozzle 10 is formed in a substantially cylindrical shape and includes a connection part 16 that is connected to the direct injection pipe 9, and a trumpet part (the tip part of the nozzle 10) 17 that is connected to the connection part 16 and expands in diameter like a trumpet.

As shown in Figures 2 to 5, a jet head nozzle 18 and a ring portion 19 are provided downstream of the nozzle 11 within the jet head 10. Note that in Figures 2 to 5, the nozzle 11 is not drawn within the jet head 10 to make it easier to understand the jet head nozzle 18 and the ring portion 19.

In this embodiment, the nozzle head 10 is provided with at least one of a nozzle head nozzle 18 and a ring portion 19 on its inner peripheral surface.

As shown in Figures 1, 2 and 5, the nozzle 18 is for atomizing the liquid medicine remaining on the inner circumferential surface of the nozzle 11 downstream of the nozzle 10, and the ring portion 19 is for atomizing the water droplets that have accumulated on the inner circumferential surface of the tip portion 17 of the nozzle 10. The nozzle 18 and the ring portion 19 are provided in this order from upstream to downstream.

The jet head nozzle 18 will be described below. As shown in Figures 6 to 11, the inner peripheral surface of the jet head 10 downstream of the nozzle 11 is provided with multiple sets (four sets in this case) of sidewall ribs 20 that protrude and face each other in the circumferential direction so as to extend in the axial direction of the jet head 10. The sets of sidewall ribs 20 are formed at 90° intervals along the circumferential direction.

The opposing sidewall ribs 20, 20 are arranged so that the space between the sidewall ribs 20, 20 tapers from the upstream side to the downstream side. In addition, an extension rib 21 is provided downstream between the sidewall ribs 20, 20 of each pair of sidewall ribs 20, connecting the sidewall ribs 20, 20 and extending from the inner peripheral surface of the nozzle head 10 toward the axis of the nozzle head 10. The opposing sidewall ribs 20, 20 and the extension rib 21 form the nozzle head nozzle 18 (see Figures 10 and 11).

The inner peripheral surface of the nozzle head 10 is provided with a protruding portion 23 that protrudes in an annular shape toward the axis of the nozzle head 10, and the extending rib 21 is included in the protruding portion 23 and forms a part of the protruding portion 23. The tip of the extending rib 21 is located closer to the axis of the nozzle head 10 than the part of the protruding portion 23 excluding the extending rib 21. The protruding portion 23 including the extending rib 21 is inclined toward the axis of the nozzle head 10 as it moves from upstream to downstream. The protruding portion 23 also functions to suitably attach the ring portion 19.

As shown in Figures 12 to 16, the ring portion 19 is configured in an annular shape, and its outer peripheral surface 24 has multiple outer grooves 25 that extend in the axial direction of the nozzle 10 and are open at both ends, spaced equally along the circumferential direction.

The ring portion 19 has, on its bottom surface (upstream surface) 26, a flat surface 27 that is connected to the outer peripheral surface 24 in an annular shape, and an inclined surface 28 that is connected to the flat surface 27 in an annular shape. The flat surface 27 is perpendicular to the axis of the ring portion 19 (spray head 10), and the inclined surface 28 is an inclined surface that is connected to the annular inner peripheral surface 29 and inclined toward the axis of the ring portion 19 as it moves from the bottom surface side, which is the upstream side, to the top surface side, which is the downstream side.

The bottom surface 26 of the ring portion 19, which has a flat surface 27 and an inclined surface 28, has a number of bottom grooves 30 recessed into the bottom surface 26 and equally spaced along the circumferential direction.

A portion 31 of the bottom groove 30 is recessed into the flat surface 27 and communicates with the bottom end (upstream end) of the outer groove 25, and is recessed into the inclined surface 28 following the inclined surface 28 (making it an inclined groove), making it a bottom groove that communicates with the inner peripheral surface 29 and opens inward.

The remaining bottom grooves 32 are provided between the outer grooves 25, 25, recessed into the flat surface 27, and recessed into the inclined surface 28 following the inclined surface 28 (to form inclined grooves), and are bottom grooves that communicate with the inner peripheral surface 29 of the ring portion 19 and open inward (see Figures 13 and 16). Of the remaining bottom grooves 32 of the ring portion 19, bottom grooves 33 at four positions spaced 90° apart in the circumferential direction extend toward the axis of the ring portion 19 (see Figures 13, 15, and 16).

As shown in Figure 5, the ring portion 19 configured in this way is attached to the protruding portion 23 (see Figures 6, 8, and 9) via a fastening means (here, a tapping screw) 34 as shown in Figures 2, 3, and 5, with the inclined surface 28 of its bottom surface 26 in close contact with the protruding portion 23 that protrudes and inclines from the inner peripheral surface of the nozzle head 10. At this time, the ring portion 19 shown in Figures 12 to 16 is rotated and attached from the state shown in Figures 12 to 16 so that the hole 42 for the tapping screw 34 fits into the female thread 43 for the tapping screw 34 of the protruding portion 23 shown in Figures 6 and 8.

In this state, the bottom grooves 33 (see Figures 13 and 16) extending from the four locations of the ring portion 19 are directed toward the axis of the nozzle head 10 and are positioned on the extending ribs 21 of the nozzle head nozzle 18, as shown in Figures 2 to 5. The open ends on the inner periphery of the four bottom grooves 33 are positioned slightly inward from the tips of the extending ribs 21 (see Figure 3).

In this state, as shown in FIG. 5, a circular gap S is formed between the flat surface 27, which is the upstream end of the outer periphery of the ring portion 19, and the outer periphery end (the inclined root portion) 35 of the protruding portion 23 facing this flat surface 27, and the multiple outer grooves 25 and multiple bottom grooves 30 communicate with this gap S.

Specifically, a portion 31 of the bottom groove 30 (see Figures 13 and 16) is connected linearly to the outer groove 25 by folding back through a gap S (see Figure 5), and the remaining portion 32 of the bottom groove 30 (see Figures 13 and 16) is not connected to the outer groove 25, but only to the gap S.

In this state, as shown in Figures 2, 3 and 5, an outer flow passage 36 is formed between the inner peripheral surface of the nozzle head 10 and the outer groove 25 of the ring portion 19, and as shown in Figure 5, an inner flow passage 37 is formed between the upper surface of the protruding portion 23 that faces the inclined surface 28 of the bottom surface 26 of the ring portion 19 and the bottom groove 30 of the inclined surface 28. This inner flow passage 37 is composed of a partial inner flow passage 39 (see Figures 5 and 16) formed by a part 31 (see Figure 16) of the bottom groove 30, and the remaining inner flow passage 40 (see Figures 5 and 16) formed by the remainder 32 (see Figure 16) of the bottom groove 30.

With the backpack-type power sprayer 100 thus configured, referring to FIG. 1, the worker carries the work machine body 1 on his back and drives the engine 4 to drive the fan, and the air from the fan in the fan case 6 is sent to the tip of the air duct 2 via the air duct 2, while the chemical solution from the chemical tank 3 is supplied to the nozzle 11 via the liquid supply hose 14. The chemical solution discharged from the nozzle 11 is sprayed in mist form from the nozzle 10 at the tip of the air duct 2 and is ready for use.

When an operator lifts the direct injection pipe 9 of the blower duct 2 to spray the chemical solution upward, water droplets accumulate on the inner surface of the tip portion (trumpet portion) 17 of the nozzle head 10, and after the spraying operation, the accumulated water droplets may drip off, or the chemical solution from the nozzle 11 may remain as water droplets on the inner surface downstream of the nozzle 11 in the upstream portion of the nozzle head 10.

According to this embodiment, the water droplets accumulated on the inner peripheral surface of the tip portion 17 of the nozzle head 10 are dealt with as follows. That is, as shown in FIG. 5, the outer flow passage 36 formed between the outer groove 25 of the outer peripheral surface 24 of the ring portion 19 and the inner peripheral surface of the nozzle head 10, the gap S communicating with the outer flow passage 36, and the inner flow passage 37 formed between the inclined surface 28 of the bottom surface 26 of the ring portion 19 and the bottom groove 30 of the inclined surface 28 are negatively pressured, so that the water droplets accumulated on the inner peripheral surface of the tip portion 17 of the nozzle head 10 are pulled by the air blown from the fan passing through the nozzle head 10, flow upstream through the outer flow passage 36 as shown by arrow A, and are sucked up from the open end of the inner flow passage 37 through the bottom groove 30, and are easily atomized by the air blown from the fan as shown by arrow B. This allows for more optimal spraying. In particular, because the wind speed is high at the axis of the nozzle 10, water droplets are more easily sucked up from the open ends of the inner flow passage 37 formed by the bottom grooves 30, which correspond to the four bottom grooves 33 (see Figures 5, 13, 15, and 16).

In addition, according to this embodiment, as shown in FIG. 5, the inner flow passage 37 formed by the bottom groove 30 of the ring portion 19 is inclined toward the axis of the nozzle head 10 from upstream to downstream, so that the water droplets are easily sucked up along the inner flow passage 37, enabling more effective spraying. Note that the inner flow passage 37 formed by the bottom groove 30 preferably directs the water droplets in a direction that does not create a headwind from the fan, and may be perpendicular to the axis of the nozzle head 10.

In addition, according to this embodiment, a gap S is formed between the flat surface 27, which is the upstream end on the outer periphery of the ring portion 19, and the outer periphery end 35 of the protruding portion 23 facing this flat surface 27. The outer flow path 36 formed by the multiple outer grooves 25 and the inner flow path 37 formed by the multiple bottom grooves 30 are connected through this gap S, so that negative pressure is reliably applied evenly to the outer flow path 36 and the inner flow path 37 through the gap S, allowing water droplets to flow more efficiently.

In addition, according to this embodiment, the number of inner flow passages 37 formed by the bottom groove 30 is greater than the number of outer flow passages 36 formed by the outer groove 25 (see Figures 13, 14, and 16), and some of the inner flow passages 39 formed by part 31 of the bottom groove 30 communicate linearly with the outer groove 25 through the gap S (see Figures 13 and 16), and the remaining inner flow passages 40 formed by the remaining part 32 of the bottom groove 30 communicate only with the gap S (see Figure 5). Therefore, negative pressure is reliably and evenly applied to each flow passage 36, 37 through the gap S, allowing the water droplets to flow more optimally, and water droplets are sucked up from more of the inner flow passages 37, resulting in more optimal spraying.

Furthermore, according to this embodiment, the following actions and effects are also achieved. That is, as shown in Figures 10 and 11, the sidewall ribs 20, 20 provided on the inner peripheral surface of the nozzle head 10, protruding so as to extend in the axial direction of the nozzle head 10 and facing each other in the circumferential direction, and the extension rib 21 provided downstream of the sidewall ribs 20, 20 on the inner peripheral surface of the nozzle head 10 to connect the sidewall ribs 20, 20 and extending from the inner peripheral surface of the nozzle head 10 toward the axial center of the nozzle head 10 form a plurality of nozzle head nozzles 18 along the circumferential direction, and in the nozzle head nozzle 18, the sidewall ribs 20, 20 and the extension rib 21 form a tapered flow path 41, which is narrowed (see Figures 2, 5, 10 and 11). As a result, negative pressure is generated in the flow path 41, and the water droplets that remain on the inner surface downstream of the nozzle 11 in the upstream part of the nozzle head 10 are collected in the tapered flow path 41 as shown by arrow C in Figure 5 and guided by said flow path 41 toward the axis of the nozzle head 10, where they can be easily atomized by the air blown by the fan as shown by arrow D, allowing for more optimal spraying.

In addition, the extension rib 21 is inclined toward the axis of the nozzle 10 from upstream to downstream, which reduces the resistance of the water droplets as they flow along the extension rib 21 that constitutes the flow path 41, allowing for more effective atomization. Note that the extension rib 21 preferably directs the water droplets in a direction that does not create a headwind from the fan, and may be perpendicular to the axis of the nozzle 10.

The present invention has been specifically described above based on the embodiments, but the present invention is not limited to the above embodiments. For example, in the above embodiments, the driving source is the engine 4, but it may be an electric motor, etc.

In addition, in the above embodiment, some of the inner flow paths 39 are provided in a straight line that communicates with the outer flow path 36 to allow water droplets to flow more efficiently, but it is also possible to have only the remaining inner flow path 40 that communicates with the gap S without some of the inner flow paths 39.

In addition, in the above embodiment, a circular gap S is provided between the upstream end 27 on the outer periphery of the ring portion 19 and the outer periphery end 35 of the protruding portion 23 facing it, so that negative pressure is reliably and uniformly applied to each flow path 36, 37 (39, 40) through the gap S. However, for example, the bottom surface 26 of the ring portion 19 may be only an inclined surface 28 without a flat surface 27, eliminating the circular gap S. In that case, it is sufficient to provide a portion of the inner flow path 39 that is linearly connected to the outer flow path 36.

In addition, in the above embodiment, a tubular inner flow passage 37 (39, 40) is formed between the upper surface of the protruding portion 23 that faces the inclined surface 28 of the bottom surface 26 of the ring portion 19 and the bottom groove 30 (31, 32) to allow water droplets to flow more efficiently, but the protruding portion 23 may not be present and the flow passage may consist only of the non-tubular bottom groove 30 (31, 32).

In addition, in the above embodiment, the jet nozzle 18 is provided upstream of the ring portion 19, but it is also possible that there is no jet nozzle 18 and only the annular protruding portion 23 for attaching the ring portion 19 is provided protruding from the inner peripheral surface of the jet head 10. Even with this configuration, the same action and effect of the ring portion 19 as described above is achieved. Also, there is no jet nozzle 18 or protruding portion 23, and the ring portion 19 may be attached to the jet head 10 by fitting, welding, etc.

In the above embodiment, the nozzle 11 is installed in the nozzle head 10, but it may be installed in any pipe upstream of the nozzle head 10, such as the direct injection pipe 9. It is also applicable to a case where another pipe, such as a curved pipe, is connected between the direct injection pipe 9 and the coiled pipe 7 and the nozzle 11 is installed in the other pipe. As such, the further the nozzle 11 is installed in the blower pipe 2 from the nozzle head 10, the greater the risk of water droplets accumulating on the inner surface of the tip portion 17 of the nozzle head 10, so it is suitable for application to such a backpack-type power sprayer.

1...working machine body, 2...air duct, 3...chemical tank, 4...engine (driving source), 6...fan case, 10...spray head, 11...nozzle, 14...liquid supply hose, 19...ring portion, 23...projection portion, 24...outer surface of ring portion, 25...outer groove, 26...bottom surface of ring portion, 27...flat surface (upstream end of outer periphery of ring portion, 28...inclined surface, 29...inner surface of ring portion, 30...bottom groove, 31...part of bottom groove, 32...remainder of bottom groove, 35...end of outer periphery of projection portion, 36...outer flow path, 37...inner flow path, 39...part of inner flow path, 40...remainder of inner flow path, 100...backpack power sprayer, S...gap.

Claims (5)

A work machine body (1) including a drive source (4), a fan, a fan case (6), and a chemical liquid tank (3) is carried on an operator's back, the fan is driven by the drive source (4), air from the fan in the fan case (6) is sent to the tip of the air pipe (2) via the air pipe (2), and the chemical liquid from the chemical liquid tank (3) is supplied to a nozzle (11) installed in the air pipe (2) via a liquid supply hose (14), and the chemical liquid discharged from the nozzle (11) is sprayed in a mist form from the tip of the air pipe (2), comprising: a spray head (10) constituting the tip of a backpack-type power sprayer (100);
The nozzle (10) includes an annular ring portion (19) attached to an inner circumferential surface downstream of the nozzle (11),
A plurality of outer grooves (25) are formed in the circumferential direction on the outer peripheral surface (24) of the ring portion (19), the outer grooves (25) extending in the axial direction of the nozzle head (10) and forming an outer flow passage (36) between the inner peripheral surface of the nozzle head (10),
The head (10) of a backpack power sprayer (100) is characterized in that a plurality of bottom grooves (30) are formed along the circumferential direction on the bottom surface (26) of the ring portion (19), which are connected to the upstream end of the outer groove (25), extend toward the axis of the head (10), and are connected to the inner surface (29) of the ring portion (19) and open inward. The bottom surface (26) of the ring portion (19) is provided with an inclined surface (28) that inclines toward the axis of the nozzle (10) from the upstream to the downstream,
2. The spray head (10) of a backpack type power sprayer (100) according to claim 1, wherein the bottom groove (30) is inclined to follow the inclined surface (28). An annular projection (23) is provided on the inner peripheral surface of the nozzle head (10) to fit the ring portion (19) in close contact with the bottom surface (26) of the ring portion (19),
The nozzle (10) of a backpack-type power sprayer (100) as described in claim 1 or 2, characterized in that an inner flow passage (37) is formed between the upper surface of the protrusion (23) facing the bottom surface (26) and the bottom groove (30). an annular gap (S) is provided between an outer peripheral upstream end (27) of the ring portion (19) and an outer peripheral end (35) of the protruding portion (23) facing the outer peripheral upstream end (27);
The nozzle (10) of the backpack type power sprayer (100) according to claim 3, characterized in that a plurality of the outer grooves (25) and a plurality of the bottom grooves (30) are in communication with the gap (S). The bottom grooves (30) are provided in greater numbers than the outer grooves (25),
A portion (31) of the bottom groove (30) and the outer groove (25) are linearly connected to each other through the gap (S),
The nozzle (10) of a backpack type power sprayer (100) according to claim 4, characterized in that the remainder (32) of the bottom groove (30) communicates only with the gap (S).

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