Abstract:
A dripper obtained by incorporating together a first member and second member, which are both resin moldings. The first member is on the side into which an irrigating solution flows, and the second member is on the side from which the irrigating solution is discharged. The dripper has an inflow part having a low-pressure stop filter function, and/or a diaphragm part for narrowing a flow path by elevating the hydraulic pressure of the irrigating solution. The dripper makes it possible to stabilize the amount of irrigating solution discharged, irrespective of the hydraulic pressure of the irrigating solution, and also makes it possible to reduce costs.

Description:
TECHNICAL FIELD 
     The present invention relates to a drip irrigation dripper (hereinafter may simply referred to as a “dripper”) and a drip irrigation apparatus including the dripper, and particularly to a dripper and a drip irrigation apparatus including the dripper which are suitable for growing plants. 
     BACKGROUND ART 
     Conventionally, as means of supplying irrigation liquids such as water or liquid fertilizer to the plants to be grown on the soil in the agricultural land, the plantation or the like, drip irrigation apparatuses that regulate the supply speed of the irrigation liquid have been employed. The use of the drip irrigation apparatus enables the saving of the irrigation liquid and the management of the growth of the plants. 
     Such a drip irrigation apparatus includes a dripper for controlling the ejection amount of the irrigation liquid per unit time when ejecting the irrigation liquid having flowed into a flow tube from the water source side (pump side) toward the plants. 
     One example of such drip irrigation apparatuses is what is called an on-line dripper. The on-line dripper is used by being inserted into holes bored in a tube wall (side wall) of polyethylene pipe or into the opening of the end portion of a microtube. The on-line dripper is conveniently employed not only in soil culture but also in nutriculture or pot culture when used for greenhouse culture, raising seedling, fruit growing, and the like. 
     As such an on-line dripper, a dripper with what is called a differential pressure control mechanism (pressure correction function) being installed is known. The dripper is configured, for example, with a three-component structure in which an elastic film (e.g., silicone rubber film) such as a diaphragm is sandwiched by an inlet side member and an outlet side member (see PTLS 1 and 2, for example). 
     The dripper utilizes the operation of the diaphragm (film) in accordance with the liquid pressure of the irrigation liquid having flowed from the inlet of the dripper to control the inflow of the irrigation liquid toward a pressure reduction channel on the downstream side of the inlet and to control the amount of the outflow of the irrigation liquid from the outlet of the dripper after pressure reduction by the pressure reduction channel. 
     More specifically, in the dripper, when the inflow liquid pressure of the irrigation liquid toward the inlet is increased to a certain level, the diaphragm that is disposed to shield the pressure reduction channel is deflected by the inflow liquid pressure toward the outlet. Due to the deformation of the diaphragm, the reduction pressure channel is opened, and thus the irrigation liquid flows into the pressure reduction channel. The irrigation liquid having flowed into the pressure reduction channel moves toward the outlet while the pressure of the irrigation liquid is reduced in the pressure reduction channel to flow out of the dripper from the outlet. When the inflow liquid pressure toward the inlet is further increased, the amount of the deflection of the diaphragm toward the outlet becomes larger. In association with the larger amount of the deflection of the diaphragm, the sectional size of the channel at the outlet is reduced, and thus the outflow of the irrigation liquid is regulated. 
     CITATION LIST 
     Patent Literature 
     
         
         PTL 1 
         U.S. Pat. No. 5,413,282 
         PTL 2 
         U.S. Pat. No. 5,820,029 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     However, the dripper has the following three problems. 
     First Problem 
     When an error occurs in assembling the above-mentioned three components for the dripper, the assembly error greatly affects the performance of the dripper. Thus, variation occurs in the operation of the diaphragm (film), causing the ejection amount of the irrigation liquid to be unstable. 
     Second Problem 
     In the dripper, the material cost is raised when silicone rubber is used for the diaphragm. 
     Third Problem 
     The dripper requires a manufacturing process in which the three components are separately manufactured, and thereafter they are further assembled. Therefore, the manufacturing cost is raised. 
     In addition, the dripper requires a liquid pressure that is high to a certain degree to open the pressure reduction channel by causing the diaphragm to be elastically deformed. Therefore, when the dripper is used under relatively high liquid pressure with a high pressure pump being employed, the original functions can be performed with no problem. However, when the dripper is used under low liquid pressure, there is a concern that the diaphragm might not be elastically deformed in a proper manner, causing the original functions not to be sufficiently performed. 
     The present invention has been achieved taking into consideration the above-mentioned problems. A first object of the present invention is to provide a dripper which makes it possible to stabilize the ejection amount of the irrigation liquid and to further achieve cost reduction by reducing the manufacturing cost, number of components and manufacturing processes, and a drip irrigation apparatus including the dripper. 
     In addition, a second object of the present invention is to provide a dripper which makes it possible to properly perform drip irrigation even when the liquid pressure of irrigation liquid is low, and a drip irrigation apparatus including the dripper. 
     Solution to Problem 
     To achieve at least the above-mentioned first object, the present invention provides the following dripper.
     [1] A drip irrigation dripper for controlling an ejection amount of irrigation liquid, having flowed from an inflow part, from an ejection port to eject the irrigation liquid, the drip irrigation dripper including:   

     a first member integrally formed of a resin material and composing one part on the inflow part side of the drip irrigation dripper; and 
     a second member integrally formed of a resin material and composing the other part on the ejection port side of the drip irrigation dripper, the second member being fixed to the first member, 
     wherein 
     the first member includes: 
     a first plate-like part having a first inner surface to be brought into close contact with the second member and a first outer surface at a side opposite to the first inner surface; 
     a first protrusion part being protruded from the first outer surface toward a side opposite to the second member and having the inflow part at a tip portion of the first protrusion part; 
     a first guide channel formed from the inflow part to the first inner surface and guiding the irrigation liquid having flowed from the inflow part toward the first inner surface; and 
     a pressure reduction channel part for forming, between the first inner surface and the second member, a pressure reduction channel connected continuously to a terminal of an inner surface of the first guide channel and allowing the irrigation liquid having been guided by the first guide channel to flow toward the ejection port while reducing a pressure of the irrigation liquid, and 
     the second member includes: 
     a second plate-like part having a second inner surface to be brought into close contact with the first inner surface and forming the pressure reduction channel together with the pressure reduction channel part and a second outer surface at a side opposite to the second inner surface; 
     a second guide channel formed from a terminal position of the pressure reduction channel at the second inner surface to the ejection port and for guiding the irrigation liquid of which pressure is reduced by the pressure reduction channel to the ejection port; and 
     a diaphragm part formed at a terminal of the first guide channel so as to form a part of an inner surface of the second guide channel and being to be deformed toward the second guide channel upon receiving a liquid pressure of the irrigation liquid having been guided by the first guide channel to regulate a width of the second guide channel so as to be smaller as the liquid pressure is increased.
     [2] The drip irrigation dripper according to [1], wherein the diaphragm part includes:   

     a dome-shaped center wall part curved so as to be protruded toward the first member; 
     a peripheral wall part connected to an outer peripheral end of the center wall part to surround the center wall part and being inclined toward the first member as being outward from the center wall part in a radial direction of the center wall part when viewed in a plan view; and wherein 
     a connection part, between the center wall part and the peripheral wall part, is configured to regulate the width of the second guide channel.
     [3] The drip irrigation dripper according to [2], wherein an end edge portion on the connection part side of each of the center wall part and the peripheral wall part has a thinner wall thickness than the connection part and portions other than the end edge portion of the center wall part.   [4] The drip irrigation dripper according to any one of [1] to [3], wherein a starting end of the second guide channel is disposed in the vicinity of the diaphragm part.   [5] The drip irrigation dripper according to any one of [1] to [4], wherein the ejection port opens to the second outer surface.   [6] The drip irrigation dripper according to any one of [1] to [4], wherein the ejection port is formed at a tip portion of a second protrusion part protruded from the second outer surface toward a side opposite to the first member.   

     In addition, to achieve at least the above-mentioned second object, the present invention provides the following drip irrigation dripper.
     [7] A drip irrigation dripper for controlling an ejection amount of irrigation liquid, having flowed from an inflow part, from an ejection port to eject the irrigation liquid, the drip irrigation dripper including:   

     a plate-like body having a first outer surface on the inflow part side of the drip irrigation dripper and a second outer surface on the ejection port side at a side opposite to the first outer surface; 
     a first protrusion part being protruded from the first outer surface toward a side opposite to the second outer surface and having the inflow part at a tip portion of the first protrusion part; 
     a first guide channel formed from the inflow part into the plate-like body and guiding the irrigation liquid having flowed from the inflow part into the plate-like body; 
     a pressure reduction channel formed so as to be connected to a terminal of the first guide channel to allow the irrigation liquid having been guided by the first guide channel to flow toward the ejection port while reducing a pressure of the irrigation liquid; and 
     a second guide channel formed from a position connected to a terminal of the pressure reduction channel inside the plate-like body to the ejection port disposed on the second outer surface side of the drip irrigation dripper and for guiding the irrigation liquid of which pressure is reduced by the pressure reduction channel to the ejection port, wherein 
     the inflow part has hydrophobicity and prevents the irrigation liquid having a liquid pressure less than a predetermined liquid pressure from flowing into the inflow part.
     [8] The drip irrigation dripper according to [7], wherein   

     the inflow part includes a substrate part that partially shields a starting end of the first guide channel, 
     the substrate part includes a plurality of inflow ports extending through the substrate part, and 
     at least a surface on a side, of the substrate part, opposite to the first guide channel has hydrophobicity.
     [9] The drip irrigation dripper according to [8], wherein an inner peripheral surface of each of the inflow ports also has hydrophobicity.   [10] The drip irrigation dripper according to [8] or [9], wherein the inflow part comprises a hydrophobic material having hydrophobicity.   [11] The drip irrigation dripper according to [8] or [9], wherein the inflow part includes hydrophobic coating having hydrophobicity.   [12] The drip irrigation dripper according to [10] or [11], wherein the inflow part has, on a hydrophobic surface, an irregular shape that reinforces the hydrophobicity.   [13] The drip irrigation dripper according to any one of [7] to [12], further including a diaphragm part formed at the terminal of the first guide channel so as to form a part of an inner surface of the second guide channel and being to be deformed toward the second guide channel upon receiving the liquid pressure of the irrigation liquid having been guided by the first guide channel, the diaphragm part being for regulating a width of the second guide channel so as to be smaller as the liquid pressure is increased.   [14] The drip irrigation dripper according to [13], including:   

     a first member integrally formed of a resin material and composing one part on the inflow part side of the drip irrigation dripper; and 
     a second member integrally formed of a resin material and composing the other part on the ejection port side of the drip irrigation dripper, the first member being fixed to the second member, 
     wherein 
     the first member includes: 
     a first plate-like part having a first inner surface to be brought into close contact with the second member and the first outer surface at a side opposite to the first inner surface; 
     the first protrusion part; 
     the first guide channel disposed from the inflow part to the first inner surface; and a pressure reduction channel part for forming, between the first inner surface and the second member, the pressure reduction channel connected continuously to a terminal of an inner surface of the first guide channel, and 
     the second member includes: 
     a second plate-like part having a second inner surface that is to be brought into close contact with the first inner surface and that forms the pressure reduction channel together with the pressure reduction channel part, and the second outer surface at a side opposite to the second inner surface; 
     the second guide channel disposed from a terminal of the pressure reduction channel part at the second inner surface to the ejection port; and 
     the diaphragm part. 
     Further, to achieve the above-mentioned first or second object, the present invention provides the following drip irrigation apparatus.
     [15] A drip irrigation apparatus including:   

     the drip irrigation dripper according to any one of [1] to [14]; and 
     a flow tube through which the irrigation liquid flows, 
     wherein 
     when the first protrusion part of the drip irrigation dripper is inserted into a tube wall or an opening of the flow tube, the irrigation liquid in the flows tube to flow into a channel of the drip irrigation dripper from the inflow part. 
     Advantageous Effects of Invention 
     With the inventions according to any of [1] to [6], the ejection amount of the irrigation liquid can be stabilized, and in addition cost reduction can be achieved by reducing the manufacturing cost, number of components and manufacturing processes. 
     In particular, with the invention according to [1], a dripper excellent in controlling the ejection amount, capable of reducing the pressure of the irrigation liquid using the pressure reduction channel and of regulating the width of the second guide channel using the diaphragm part can be manufactured with less assembly error with only two components of the first member and the second member. Therefore, it is possible to stabilize the ejection amount of the irrigation liquid, and to achieve cost reduction by reducing the manufacturing cost, number of components and manufacturing processes. 
     In addition, with the invention according to [2], the diaphragm part can be formed into a suitable shape to be deformed toward a predetermined portion facing the diaphragm part in the inner surface of the second guide channel upon efficiently receiving the liquid pressure of the irrigation liquid before pressure reduction. Therefore, it is possible to regulate the channel width more properly. 
     In addition, with the invention according to [3], the rigidity near the connection part to be used for regulating the width of the channel in the diaphragm part is partially weakened, thereby enabling the connection part to be moved more efficiently depending on the liquid pressure. Therefore, it is possible to regulate the channel width more simply and properly. 
     In addition, with the invention according to [4], the shape of a metal mold for molding the second member from a resin can be simplified, compared with the case where the starting end of the second guide channel is disposed away from the diaphragm part. Therefore, it is possible to further reduce the manufacturing cost. 
     In addition, with the invention according to [5], the configuration of the second member can be simplified. Therefore, it is possible to further reduce the manufacturing cost. 
     In addition, with the invention according to [6], it is possible to select a suitable configuration to connect a tube to the ejection port to adjust the ejecting direction. 
     In addition, with the inventions according to any of [7] to [14], even when the liquid pressure of the irrigation liquid is low, drip irrigation can be performed properly. 
     In particular, with the invention according to [7], the lower limit of the liquid pressure of the irrigation liquid flowing from the inflow part can be controlled so as to be low due to hydrophobicity of the inflow part. Therefore, even when the liquid pressure of the irrigation liquid is low, the irrigation liquid can be properly used for the drip irrigation. 
     In addition, with the invention according to [8], a portion, out of the inflow part, to be exposed to the irrigation liquid outside of the dripper has hydrophobicity. Therefore, it is possible to regulate the inflow of the irrigation liquid more properly. 
     In addition, with the invention according to [9], capillary action in the inflow port can be surely suppressed. Therefore, it is possible to regulate the inflow of the irrigation liquid more properly. 
     In addition, with the invention according to [10], the hydrophobicity of the inflow part can be achieved with a smaller number of components. 
     In addition, with the invention according to [11], the hydrophobicity of the inflow part does not depend on the material of the inflow part. Therefore, it is possible to further enhance the freedom in selecting the material of the inflow part. 
     In addition, with the invention according to [12], the lower limit of the liquid pressure of the irrigation liquid flowing from the inflow part can also be adjusted to be somewhat higher. Therefore, it is possible to further enhance the freedom in selecting the pressure of the inflow liquid during the use of the dripper under low pressure. 
     In addition, with the invention according to [13], even when the dripper is used under high pressure, the flow rate of the irrigation liquid toward the ejection port can be regulated by the diaphragm part. Therefore, it is possible to control the ejection amount of the irrigation liquid more properly. In addition, the diaphragm part does not shield the pressure reduction channel, so as not to be involved in the regulation of the inflow into the pressure reduction channel. Therefore, with the invention according to [13], the diaphragm part does not constitute a cause for raising the lower limit of the liquid pressure to be used toward the high pressure side (i.e., a cause for hindering the drip irrigation using low-pressure irrigation liquid). 
     In addition, with the invention according to [14], the dripper excellent in controlling the ejection amount can be manufactured with less assembly error with only two components made of a resin material. Therefore, it is possible to stabilize the ejection amount of the irrigation liquid, and to achieve further cost reduction by reducing the manufacturing cost, number of components and manufacturing processes. 
     In addition, with the invention according to [15], it is possible to stabilize the ejection amount of the irrigation liquid, having flowed into the inflow part from the flow tube, from the ejection port, and to achieve cost reduction by reducing the manufacturing cost, number of components and manufacturing processes. Alternatively, with the invention according to [15], even when the liquid pressure of the irrigation liquid flowing through the flow tube is low, it is possible to allow this irrigation liquid to flow into the channel of the dripper to use the irrigation liquid for drip irrigation properly. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective bird&#39;s-eye view illustrating a dripper according to an embodiment of the present invention; 
         FIG. 2  is a transparent bird&#39;s-eye view illustrating the dripper; 
         FIG. 3  is a perspective upward view of the dripper; 
         FIG. 4  is a transparent upward view of the dripper; 
         FIG. 5  is a bottom view of a first member in the dripper; 
         FIG. 6  is a top view of a second member in the dripper; 
         FIG. 7  is a front view of the dripper; 
         FIG. 8  is a sectional view of the dripper taken along line A-A in  FIG. 7 ; 
         FIG. 9  is a sectional view of the dripper taken along line B-B in  FIG. 8 ; 
         FIG. 10  is a sectional view schematically illustrating a drip irrigation apparatus according to an embodiment of the present invention; 
         FIG. 11  is an enlarged sectional view of an inflow part in the dripper; 
         FIG. 12  is an enlarged sectional view illustrating one example of means to embody a low-pressure stop filter function of the inflow part; 
         FIG. 13  is an enlarged sectional view illustrating another example of means to embody the low-pressure stop filter function of the inflow part; 
         FIG. 14A  is an enlarged sectional view of the inflow part before the inflow of irrigation liquid,  FIG. 14B  is an enlarged sectional view of the inflow part when the liquid pressure of irrigation liquid is less than fracture hydraulic pressure, and  FIG. 14C  is an enlarged sectional view of the inflow part into which irrigation liquid having equal to or more than fracture hydraulic pressure flows; 
         FIG. 15  is an enlarged sectional view of a diaphragm part and its periphery in the dripper; 
         FIG. 16A  is an enlarged sectional view of the diaphragm part and its periphery before the inflow of the irrigation liquid into the dripper,  FIG. 16B  is an enlarged sectional view of the diaphragm part and its periphery having been deformed upon receiving the liquid pressure of the irrigation liquid having flowed into the dripper, and  FIG. 16C  is an enlarged sectional view of the diaphragm part and its periphery having been further deformed upon receiving the liquid pressure of the irrigation liquid having flowed into the dripper; 
         FIG. 17  is a perspective upward view illustrating a first modification of the dripper according to the present invention; 
         FIG. 18  is a perspective upward view illustrating a second modification of the dripper according to the present invention; and 
         FIG. 19  is an enlarged sectional view of a diaphragm part and its periphery in a third modification of the dripper according to the present invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     In the following, embodiments of a dripper according to the present invention and a drip irrigation apparatus including the dripper will be described with reference to  FIGS. 1 to 19 . 
       FIG. 1  is a perspective bird&#39;s-eye view illustrating dripper  1  in the present embodiment.  FIG. 2  is a transparent birds-eye view illustrating dripper  1 .  FIG. 3  is a perspective upward view of dripper  1 .  FIG. 4  is a transparent upward view of dripper  1 .  FIG. 5  is a bottom view of first member  2  to be described later in dripper  1 .  FIG. 6  is a top view of second member  3  to be described later in dripper  1 .  FIG. 7  is a front view of dripper  1 .  FIG. 8  is a sectional view of dripper  1  taken along line A-A in  FIG. 7 .  FIG. 9  is a sectional view of dripper  1  taken along line B-B in  FIG. 8 .  FIG. 10  is a schematic sectional view illustrating drip irrigation apparatus  4  in the present embodiment. 
     As illustrated in  FIG. 10 , drip irrigation apparatus  4  is composed of elongated tube  5  as a flow tube in which the irrigation liquid flows, and dripper  1  inserted into tube  5  through through-hole  51  bored in the side wall of tube  5 . 
     It is noted that, while not illustrated, dripper  1  may be used by being inserted into the opening of an end portion of the tube. 
     Dripper  1 , being inserted into tube  5  in this manner, controls the ejection amount of the irrigation liquid per unit time when the irrigation liquid in tube  5  is ejected to the outside. 
     It is noted that, while one dripper  1  and one through-hole  51  are illustrated for convenience in  FIG. 10 , actually a plurality of drippers  1  and through-holes  51  are often disposed along the longitudinal direction of tube  5  at a predetermined interval. 
     In addition, in  FIG. 10 , the right and left sides of the channel in tube  5  correspond to the upstream side and the downstream side, respectively. 
     Dripper  1  will be described further in detail. As illustrated in  FIGS. 1 to 10 , dripper  1  is formed by fixing first member  2  and second member  3  to each other. Each of first member  2  and second member  3  is integrally formed of a resin material. The method of fixing first member  2  and second member  3  may be joining by means of adhesion using an adhesive, welding, or the like, or alternatively may be pressure joining by means of pressing. In addition, first member  2  and second member  3  may be formed of the same resin material, or alternatively may be formed of different resin materials. Further, as the resin material, an inexpensive resin material such as polypropylene may be employed. Furthermore, each of first member  2  and second member  3  may be integrally molded by injection molding. 
     [Specific Configuration of First Member] 
     &lt;First Plate-Like Part&gt; 
     As illustrated in  FIGS. 1 to 5  and  FIGS. 7 to 10 , first member  2  has disc-shaped first plate-like part  21 . The shape of first plate-like part  21  is circular in a plan view. However, the shape of the first plate-like part in the present invention does not need to be limited to a disc shape; for example, rectangular or other polygonal plate shapes may be employed. 
     First plate-like part  21  has first inner surface (bottom surface in  FIGS. 8 and 9 ) 211 to be brought into close contact with second member  3 , and first outer surface (top surface in  FIGS. 8 and 9 )  212  at the side opposite to first inner surface  211 . 
     First inner surface  211  and first outer surface  212  are formed so as to be planes disposed parallel to each other across the thickness of first plate-like part  21 . 
     As illustrated in  FIG. 5 , annular belt-shaped recess  2111  is formed at the center of first inner surface  211 . As illustrated in  FIG. 8 , rim part  2112  of first inner surface  211  is protruded toward second member  3 . First plate-like part  21  composes plate-like body  11  (see  FIGS. 1 and 8 ) together with second plate-like part  31  to be described later. 
     &lt;First Protrusion Part and Inflow Part&gt; 
     As illustrated in  FIGS. 1 to 4  and  FIGS. 7 to 10 , first member  2  has first protrusion part  22 . First protrusion part  22  is protruded from the center portion of first outer surface  212  of first plate-like part  21  toward the side opposite to second member  3  (upward in  FIGS. 7 to 9 ). 
     The outer peripheral surface of first protrusion part  22  is formed of a cylindrical surface from the base end portion (lower end portion) to the tip portion (upper end portion) in the protrusion direction of first protrusion part  22 , and of a frustum surface formed at the tip side of the cylindrical surface. The frustum surface is a tapered surface formed such that the outer diameter of first protrusion part  22  is gradually decreased toward the tip side. The frustum surface is connected to the cylindrical surface through a plane expanding outwardly in the radial direction from that cylindrical surface. The frustum surface functions as a stopper when dripper  1  is inserted into tube  5  (see  FIG. 10 ). However, the outer peripheral surface of the first protrusion part in the present invention does not need to be limited to the cylindrical surface and the frustum surface; a square tube surface, a prismoid surface, or the like may also be employed. 
     In addition, first protrusion part  22  is formed into a hollow shape (tubular shape) by the presence of first guide channel  23  to be described later. 
     Further, inflow part  221  is formed near the tip portion of first protrusion part  22 .  FIG. 11  is an enlarged sectional view of inflow part  221 . 
     As illustrated in  FIGS. 8 ,  9  and  11 , inflow part  221  has substrate part  2211  orthogonal to the longitudinal direction of first protrusion part  22 , and a plurality of inflow ports  2212  extended vertically (in other words, in the longitudinal direction of first protrusion part  22 ) through substrate part  2211 . Inflow port  2212  is a column-shaped pore. 
     As illustrated in  FIG. 11 , the starting end portion (upper end portion) of first guide channel  23  is partially shielded from the outer space outside of dripper  1  by substrate part  2211  of inflow part  221 , and is partially opened to the outer space through inflow ports  2212  extending through substrate part  2211 . 
     It is noted that, while in  FIG. 5  each inflow port  2212  is disposed at an intersection of the rectangular lattice, the disposition of the inflow ports in the present invention does not need to be limited to one as in  FIG. 5 . 
     Inflow part  221  is provided with a low-pressure stop filter function for not allowing irrigation liquid having less than a predetermined pressure (e.g., 0.005 MPa) to flow into the channel of dripper  1 . 
     There are several possibilities to be considered for the means to embody the low-pressure stop filter function. For example, when polypropylene is used as a material for dripper  1 , the low-pressure stop filter function can be imparted to inflow part  221 , since polypropylene itself is a high water-repellent (hydrophobic) material with a low surface energy. 
     Other than that, as illustrated in  FIG. 12 , for example hydrophobic coating C such as fluorine coating by means of a fluorine coating agent is applied to surface  22111  of substrate part  2211  outside of dripper  1  (in other words, at the side opposite to first guide channel  23  to be described later) and, as needed, to the inner peripheral surface  22121  of inflow port  2212 . The hydrophobic coating C reduces the surface energy. In this case, the hydrophobic coating C can impart the low-pressure stop filter function to inflow part  221  locally without depending on the material of dripper  1 . 
     In addition, hydrophobicity may be reinforced by, for example, forming an irregular shape on the hydrophobic surface, as needed. The hydrophobic surface may be formed with the above-mentioned material or with the hydrophobic coating. As illustrated in  FIG. 13 , the irregular shape may be burr  22122  formed at the upper opening edge of inflow port  2212 , or may be an irregular shape formed by transferring the irregular shape intentionally formed on the transfer surface of a metal mold. 
     In addition, it is also possible to optimize the low-pressure stop filter function by adjusting the inner diameter, pitch, number, opening shape and wall thickness of inflow port  2212 , the surface roughness of inflow part  221 , and the like. 
     When the liquid pressure of the irrigation liquid in tube  5  is raised to a predetermined pressure (fracture hydraulic pressure), inflow part  221  allows the irrigation liquid to flow into dripper  1  through inflow port  2212 . Here, from the viewpoint of allowing dripper  1  in the present embodiment to favorably function when being used under low pressure, it is desirable to select, as the predetermined pressure, a sufficiently low pressure of about 0.005 MPa exemplified earlier. However, the “predetermined pressure” is embodied (set) depending on the degree of hydrophobicity of inflow part  221 . Accordingly, when imparting hydrophobicity to inflow part  221 , necessary hydrophobicity-causing factors (the above-described material of inflow part  221 , type and film thickness of the hydrophobic coating, surface shape of the hydrophobic surface, and the like) may be selected based on experiment results or the like, taking into consideration the relationship between the hydrophobicity and the predetermined pressure that should be set. 
       FIGS. 14A ,  14 B and  14 C illustrate specific examples of the operation of inflow part  221 . 
     First, as illustrated in  FIG. 14A , when the external liquid pressure to which inflow part  221  is exposed is 0 MPa (in other words, there is no irrigation liquid in tube  5 ), the inflow regulation of the irrigation liquid by inflow part  221  is not performed as a matter of course. 
     Next, as illustrated in  FIG. 14B , when the external liquid pressure is less than 0.005 MPa (the above-mentioned fracture hydraulic pressure), the low-pressure stop filter function works based on the hydrophobicity of inflow part  221 . As a result, the irrigation liquid outside of inflow part  221  (in other words, in tube  5 ) is dammed at outer surface  22111  of substrate part  2211  and at the upper opening end of inflow port  2212 . Therefore, the inflow into first guide channel  23  of dripper  1  is regulated (prevented). 
     Next, as illustrated in  FIG. 14C , when the external liquid pressure is equal to or more than 0.005 MPa, the external liquid pressure surpasses the hydrophobicity of inflow part  221 . Therefore, the irrigation liquid outside of inflow part  221  flows into first guide channel  23  of dripper  1  from inflow port  2212 . 
     As has been described above, when the liquid pressure of the irrigation liquid in tube  5  is raised to the predetermined pressure (fracture hydraulic pressure), inflow part  221  allows the irrigation liquid to flow into dripper  1  through inflow port  2212 . 
     &lt;First Guide Channel&gt; 
     As illustrated in  FIGS. 8 and 9 , first member  2  has first guide channel  23  as the most upstream channel of dripper  1 . 
     As illustrated in  FIGS. 8 and 9 , first guide channel  23  is formed from inflow part  221  to first inner surface  211  of first plate-like part  21  (in other words, toward the inside of plate-like body  11 ). For example, first guide channel  23  is a hole extending through first protrusion part  22  along the longitudinal direction of first protrusion part  22 . 
     First guide channel  23  guides the irrigation liquid having flowed from inflow part  221  toward first inner surface  211  (downward in  FIGS. 8 and 9 ). 
     It is noted that, while channel inner surface  231  (in other words, inner peripheral surface of first protrusion part  22  defining the shape of first guide channel  23 ) of first guide channel  23  is formed so as to be a cylindrical surface concentric with the outer peripheral surface of first protrusion part  22 , the shape of the channel inner surface in the present invention does not need to be limited to such a shape; for example, a square tube surface, or the like may also be employed. 
     &lt;Pressure Reduction Channel&gt; 
     As illustrated in  FIG. 5 , first member  2  has pressure reduction channel part  213  provided as a recess on first inner surface  211  of first plate-like part  21 . 
     As illustrated in  FIG. 5 , pressure reduction channel part  213  is composed of groove part  213  connected continuously to the terminal (in other words, downstream end) of channel inner surface  231  of first guide channel  23 . 
     As illustrated in  FIG. 5 , groove part  213  is formed into a substantially U-shape. That is, groove part  213  is formed in such a shape as to extend outwardly in a serpentine manner in the radial direction of first inner surface  211  from the terminal of channel inner surface  231  of first guide channel  23 , and then to turn back before rim part  2112  of first inner surface  211  to return to the vicinity of the terminal of channel inner surface  231  without serpentine. That is, when first inner surface  211  is viewed in a plan view, groove part  213  includes a zig-zag part being extended along the radial direction of first inner surface  211 , and a turn-back part including a linear portion and being extended from the tip portion of the zig-zag part to a position overlapping the starting end of second guide channel to be described later. 
     Pressure reduction channel part  213  forms pressure reduction channel  8  (see  FIG. 2 ) together with second member  3 . Pressure reduction channel  8  allows the irrigation liquid having been guided by first guide channel  23  to flow toward ejection port  321  to be described later while reducing the pressure of the irrigation liquid. 
     It is noted that the shape of the pressure reduction channel part in the present invention does not need to be limited to the shape illustrated in  FIG. 5  as long as pressure reduction channel  8  can be connected to the terminal of first guide channel  23 . In addition, a plurality of pressure reduction channel parts  213  may be provided. 
     [Specific Configuration of Second Member] 
     &lt;Second Plate-Like Part&gt; 
     On the other hand, as illustrated in  FIGS. 1 to 4  and  FIGS. 6 to 10 , second member  3  has second plate-like part  31 . The shape of second plate-like part  31  is a circular disc-shape being concentric with and having the same diameter as that of first plate-like part  21  in a plan view. However, the shape of the second plate-like part in the present invention does not need to be limited to a disc shape; for example, rectangular or other polygonal plate shapes may be employed. 
     Second plate-like part  31  has second inner surface (top surface in  FIGS. 8 and 9 ) 311 to be brought into close contact with first inner surface  211  in first plate-like part  21 , and second outer surface (bottom surface in  FIGS. 8 and 9 )  312  at the side opposite to second inner surface  311 . 
     Second inner surface  311  and second outer surface  312  are formed so as to be planes disposed parallel to each other across the thickness of second plate-like part  31 . 
     It is noted that second inner surface  311  may be joined to first inner surface  211 . 
     Rim part  3111  of second inner surface  311  is concaved by the same dimension as the protrusion dimension of rim part  2112  of first inner surface  211  (see  FIG. 8 ). It is also possible to use rim parts  3111  and  2112  for positioning first member  2  and second member  3 . 
     &lt;Second Protrusion Part and Ejection Port&gt; 
     As illustrated in  FIGS. 1 to 4  and  FIGS. 7 to 10 , second member  3  has second protrusion part  32 . Second protrusion part  32  is protruded from the center portion of second outer surface  312  of second plate-like part  31  toward the side opposite to first member  2  (downward in  FIGS. 7 to 9 ). 
     The outer peripheral surface of second protrusion part  32  is formed of a cylindrical surface from the base end portion (upper end portion) of second protrusion part  32  to the tip portion (lower end portion) in the protrusion direction of second protrusion part  32 , and of a frustum surface formed at the tip side of that cylindrical surface. The frustum surface is connected to the cylindrical surface through a plane expanding outwardly in the radial direction from that cylindrical surface. However, the outer peripheral surface of the second protrusion part in the present invention does not need to be limited to the cylindrical surface and the frustum surface; a square tube surface, a prismoid surface, or the like may also be employed. 
     In addition, second protrusion part  32  is formed into a hollow shape (tubular shape) by the presence of second guide channel  33  to be described later. 
     Further, ejection port  321  formed of a circular opening is formed at the tip portion of second protrusion part  32 . 
     &lt;Second Guide Channel&gt; 
     As illustrated in  FIGS. 8 ,  9  and  15 , second member  3  has second guide channel  33 . 
     As illustrated in  FIGS. 8 and 15 , second guide channel  33  is formed from a position, opposed to terminal (in other words, downstream end)  213 E of pressure reduction channel part  213 , on second inner surface  311  of second plate-like part  31  (in other words, inside plate-like body  11 ) to ejection port  321 . For example, second guide channel  33  includes a hole extending through second protrusion part  32  along the longitudinal direction of second protrusion part  32 . 
     More specifically, as illustrated in  FIG. 15 , second guide channel  33  is composed of starting end channel section (first section)  331  as a starting end portion, width-regulated channel section (second channel)  332  connected to the downstream side of first section  331 , and ejection guide channel section (third section)  333  connected to the downstream side of second section  332 . In first section  331 , the channel inner surface is formed into a rectangular shape. In addition, second section  332  is formed of a relatively narrow space surrounded by bottom surface (hereinafter, referred to as inner bottom surface)  3321  in the channel inner surface formed in second plate-like part  31  and of diaphragm part  34  to be described later. It is noted that inner bottom surface  3321  is continuously connected to inner bottom surface  3311  (see  FIG. 15 ) of first section  331  in such a shape as to be in the same plane at the radially inner side. Further, the channel inner surface of third section  333  is formed so as to be a cylindrical surface concentric with first guide channel  23 . The third section in the present invention does not need to be limited to such a configuration, and may be formed to have a square tube surface, or the like, for example. 
     In addition, in second guide channel  33 , first section  331  is designed to be opposed to terminal  8 E (see  FIG. 15 ) of pressure reduction channel  8  so as to bring first inner surface  211  and second inner surface  311  into close contact with each other, thereby allowing second guide channel  33  to communicate with pressure reduction channel  8 . 
     Second guide channel  33  guides the irrigation liquid after pressure reduction by pressure reduction channel  8  to ejection port  321 . 
     &lt;Diaphragm Part&gt; 
     Furthermore, as illustrated in  FIGS. 8 to 10  and  15 , second member  3  has diaphragm part  34  at a position corresponding to the terminal of first guide channel  23  on second inner surface  311  of second plate-like part  31 . 
     Diaphragm part  34  is formed so as to separate first guide channel  23  and second guide channel  33  from each other except communication through pressure reduction channel  8 . That is, first guide channel  23  and third section  333  are separated from each other by diaphragm part  34 , and communicate with each other through pressure reduction channel  8 , first section  331  and second section  332 . 
     Further, diaphragm part  34  forms a part of the channel inner surface of second guide channel  33 , and, as described above, forms second section  332  together with inner bottom surface  3321 . 
     Diaphragm part  34  receives the liquid pressure of the irrigation liquid having been guided by first guide channel  23 . That irrigation liquid is led to pressure reduction channel  8 . 
     In addition, diaphragm part  34  is deformed toward inner bottom surface  3321  (i.e., a portion facing diaphragm part  34  in the channel inner surface of second guide channel  33 ) by the liquid pressure of the irrigation liquid. Diaphragm part  34  is deformed such that the width of the channel of second section  332  (i.e., the width of the channel of second guide channel  33  at a position where diaphragm part  34  is deformed) becomes smaller, as that liquid pressure is increased. 
     More specifically, as illustrated in  FIG. 15 , diaphragm part  34  has dome-shaped center wall part  341  curved so as to be protruded toward first member  2 , and peripheral wall part  342  connected to the outer peripheral end of center wall part  341  to surround center wall part  341 . Peripheral wall part  342  is inclined toward first member  2  as being outward from center wall part  341  in the radial direction (radial direction of center wall part  341  when viewed in a plan view). That is, peripheral wall part  342  is formed in such a shape as to be gradually expanded toward inflow part  221 . Peripheral wall part  342  is connected to the inner rim of the lower end of first guide channel  23  by the close contact between first member  2  and second member  3 . 
     In addition, one portion  3431  in the circumferential direction (see  FIG. 15 ), out of connection part  343  between center wall part  341  and peripheral wall part  342 , is disposed at a position near inner bottom surface  3321  so as to face inner bottom surface  3321  from above in  FIG. 15 . For example, diaphragm part  34  is disposed such that the surface of portion  3431  is a plane orthogonal to a direction in which diaphragm part  34  is deformed (longitudinal direction of first guide channel  23 ). 
     Portion (hereinafter, referred to as “channel width-regulating portion” or “fourth portion”)  3431  is a part of connection part  343 , and regulates the width of the channel of second section  332 . 
     It is noted that portions near connection part  343  at each of center wall part  341  and peripheral wall part  342  (end edge portion of center wall part  341  and end edge portion of peripheral wall part  342 ) are desirably formed to be thinner, compared with connection part  343  and portions other than the portion near connection part  343  at center wall part  341 . For example, each of center wall part  341  and peripheral wall part  342  is desirably formed so as to have a thickness being gradually decreased toward connection part  343 . 
     As illustrated in  FIG. 6 , first section  331  is disposed at a position near the radially outer side of diaphragm part  34 . 
     Here,  FIGS. 16A ,  16 B and  16 C illustrate specific examples of the operation of diaphragm part  34 . 
     First, as illustrated in  FIG. 16A , when the liquid pressure is 0 MPa, i.e., there is no irrigation liquid in first guide channel  23 , the width regulation of second section  332  by diaphragm part  34  is not performed as a matter of course. That channel width in this case is 0.25 mm. It is noted that, as illustrated in  FIG. 16A , the channel width is the shortest distance between fourth portion  3431  of diaphragm part  34  and inner bottom surface  3321 . 
     Next, as illustrated in  FIG. 16B , when the liquid pressure is equal to or more than 0.005 MPa (the above-mentioned fracture hydraulic pressure) and less than 0.05 MPa, diaphragm part  34  is deformed by the liquid pressure of the irrigation liquid in first guide channel  23 . Therefore, fourth portion  3431  moves toward (downward) inner bottom surface  3321 . Thus, the channel width is regulated to 0.15 mm. 
     Next, as illustrated in  FIG. 16C , when the liquid pressure is equal to or more than 0.05 MPa and equal to or less than 0.1 MPa, diaphragm part  34  is deformed further compared with the state illustrated in  FIG. 16B . Therefore, fourth portion  3431  moves further toward inner bottom surface  3321 . Thus, the channel width is regulated to 0.1 mm. 
     [Operation and Effect of Present Embodiment]. 
     According to the present embodiment, the irrigation liquid in tube  5  having reached the predetermined pressure flows into dripper  1  through inflow port  2212  of inflow part  221 . 
     According to the present embodiment, the lower limit of the liquid pressure of the irrigation liquid flowing into pressure reduction channel part  8  can be controlled to be lower than the conventional case (i.e., the case of shielding the pressure reduction channel using the elasticity of the diaphragm) using hydrophobicity of inflow part  221 . Therefore, even when the liquid pressure of the irrigation liquid outside of dripper  1  is low, that irrigation liquid can be properly used for drip irrigation. 
     In addition, at least surface  22111  outside of substrate part  2211  in inflow part  221  is formed so as to have hydrophobicity, thereby allowing a portion exposed to the external liquid pressure in inflow part  221  to have hydrophobicity. Therefore, the inflow of the irrigation liquid into the channel of dripper  1  can be properly controlled. 
     Further, when hydrophobicity is imparted to inner peripheral surface  22121  of inflow port  2212 , capillary action in inflow port  2212  can be surely suppressed, making it possible to control the inflow of the irrigation liquid more properly. 
     Furthermore, when inflow part  221  is formed of a hydrophobic material, the hydrophobicity of inflow part  221  can be achieved with a smaller number of components. 
     In addition, when the hydrophobicity of inflow part  221  is achieved by hydrophobic coating, the hydrophobicity of inflow part  221  does not depend on the material of inflow part  221 , and thus it is possible to further enhance the freedom in selecting the material of inflow part  221 . 
     Further, when an irregular shape is formed on the hydrophobic surface of inflow part  221 , the lower limit of the liquid pressure of the irrigation liquid flowing into the channel of dripper  1  can be adjusted to be somewhat higher. Therefore, it is possible to enhance the freedom in selecting the pressure of the inflow liquid during the use of dripper  1  under low pressure. 
     Furthermore, diaphragm part  34  provided in dripper  1  makes it possible to properly control the ejection amount of the irrigation liquid even when used under high pressure. 
     The irrigation liquid having flowed into dripper  1  reaches the terminal, where diaphragm part  34  is disposed, of first guide channel  23  through first guide channel  23 . 
     The irrigation liquid having reached the terminal of first guide channel  23  deforms diaphragm part  34  with its liquid pressure, while being inhibited from moving forward in such a manner as to be dammed by diaphragm part  34 , and as a result is led to pressure reduction channel  8  sideward as an escape. 
     The irrigation liquid introduced into pressure reduction channel  8  undergoes pressure reduction due to pressure loss caused by the shape of the channel of pressure reduction channel  8 . 
     The irrigation liquid of which pressure is reduced by pressure reduction channel  8  flows into first section  331  in second guide channel  33  connected to terminal  8 E of pressure reduction channel  8 , and then passes through second section  332 . 
     At that time, diaphragm part  34  is deformed by the liquid pressure of the irrigation liquid with which first guide channel  23  is filled, such that fourth portion  3431  moves toward inner bottom surface  3321 . Therefore, the width of the channel of second section  332  is decreased by an amount according to the amount of this deformation. 
     Accordingly, the flow rate of the irrigation liquid passing through second section  332  (flow rate moving toward third section  333  and ejection port  321  all at once) is regulated by the influence of the regulation on the channel width by diaphragm part  34 . 
     Here, two cases will be discussed in which the liquid pressure of the irrigation liquid flowing into dripper  1  is relatively high and is relatively low. The examples of the causes for such two cases include a position at which dripper  1  is attached on tube  5  (whether near to or distant from a pump), performance of the pump itself (whether high-pressure pump or low-pressure pump), and change of the performance of the pump itself over time. 
     First, when the pressure of the irrigation liquid is high, the inflow amount of the irrigation liquid into the channel of dripper  1  becomes relatively larger, but at the same time the amount of deformation of diaphragm part  34  becomes relatively larger. Thus, the flow rate of the irrigation liquid to be regulated by diaphragm part  34  also becomes relatively larger. Therefore, the ejection amount of the irrigation liquid from ejection port  321  does not become excessively large. 
     On the other hand, when the pressure of the irrigation liquid is low, the inflow amount of the irrigation liquid into the channel of dripper  1  becomes relatively smaller, but at the same time the amount of deformation of diaphragm part  34  becomes relatively smaller. Thus, the flow rate of the irrigation liquid to be regulated by diaphragm part  34  also becomes relatively smaller. Therefore, the ejection amount of the irrigation liquid from ejection port  321  does not become excessively small. 
     Thus, the ejection amount of the irrigation liquid from ejection port  321  can be suitably controlled so as to have less variation (such that the variation of that ejection amount is regulated to 5 to 10%, for example), irrespective of the liquid pressure of the irrigation liquid at the time of flowing into dripper  1 . 
     In addition, diaphragm part  34  has a structure in which pressure reduction channel  8  is not shielded, unlike the techniques set forth in PTLS 1 and 2, and pressure reduction channel  8  is constantly opened. Therefore, in the present embodiment, the inflow of the irrigation liquid into pressure reduction channel  8  is not regulated. Therefore, the presence of diaphragm part  34  does not constitute a cause for raising the lower limit of the liquid pressure of the irrigation liquid available for drip irrigation toward the high pressure side. 
     In addition, diaphragm part  34  is integrally molded with the same resin material as that of second member  3 . Therefore, in the present embodiment, such dripper  1  excellent in controlling the ejection amount of the irrigation liquid can be manufactured at a low cost and with less processes with only two components of first member  2  and second member  3  made of a resin material. In particular, there are quite large advantages in terms of costs and manufacturing efficiency when compared with the case of assembling a diaphragm made of an expensive material such as silicone rubber as an individual component. 
     In addition, since diaphragm part  34  is assembled into second member  3  as an integrally molded product, malfunction of diaphragm part  34  due to assembly error is less likely to occur, contributing to the stabilization of the ejection amount of the irrigation liquid. 
     Further, diaphragm part  34  is capable of regulating the channel width properly and efficiently by utilizing the pressure difference between the irrigation liquid in pressure reduction channel  8  after pressure reduction by pressure reduction channel  8  and the irrigation liquid in first guide channel  23  to which diaphragm part  34  is exposed. That is, the reduced liquid pressure of the irrigation liquid in second section  332  is sufficiently low. Therefore, that liquid pressure does not hinder the deformation operation of diaphragm part  34  by the irrigation liquid in first guide channel  23  having a relatively high pressure. 
     Furthermore, first section  331  of second guide channel  33  is disposed near diaphragm part  34 . Therefore, compared with the case where first section  331  is disposed away from diaphragm part  34 , the shape of a metal mold in which second member  3  is molded with resin can be simplified, and thus the manufacturing cost can be further reduced. 
     In addition, diaphragm part  34  is deflected so as to cancel the curvature toward first guide channel  23  utilizing the elasticity of the resin material to expand outwardly in the radial direction upon receiving the liquid pressure at center wall part  341  from first guide channel  23  side. At the same time, peripheral wall part  342  is rotated about a contact point where peripheral wall part  342  intersects with second plate-like part  31  as a rotation axis. Therefore, fourth portion  3431  can be smoothly displaced toward inner bottom surface  3321  of second section  332 . 
     Thus, diaphragm part  34  is formed into a suitable shape to be deformed toward inner bottom surface  3321  upon efficiently receiving the liquid pressure of the irrigation liquid in first guide channel  23 . Accordingly, the channel width can be regulated more properly. Such an effect can be further enhanced by forming a portion near fourth portion  3431  in diaphragm part  34  to be thinner. It is noted that the channel width may be regulated more stably by forming fourth portion  3431  to be further thicker. 
     As has been described above, according to the present embodiment, the dripper includes at least a pipe for penetrating the tube wall of the tube through which the irrigation liquid is supplied, a flange part extending outwardly from the outer periphery of that pipe, a partition wall that closes the inside of that pipe in that flange part, and a bypass channel that is formed inside the flange part and allows communication between two portions, of the pipe, partitioned by the partition wall, and that bypass channel includes a pressure reduction channel for reducing the pressure of the irrigation liquid flowing through the bypass channel. In addition, the dripper is composed of the above-mentioned first member and second member that divide the pipe part and flange part into two portions, and the partition wall is integrally formed with either of first member or second member. 
     In addition, when at least the partition wall is a diaphragm part that moves in such a direction so as to close the inside of the pipe or the bypass channel upon receiving the pressure of the irrigation liquid having flowed into the pipe, it is possible to provide a dripper enabling the ejection amount of the irrigation liquid to be stabilized, and cost reduction to be achieved by reducing the manufacturing cost, number of components and manufacturing processes, and a drip irrigation apparatus including the dripper. In this case, the above-mentioned low pressure stop filter function does not need to be provided at the inflow port disposed at the end of the pipe disposed in the tube. However, the dripper further including the above-mentioned low pressure stop filter function is more effective from the viewpoint of stabilizing the drop of the irrigation liquid when the liquid pressure of the irrigation liquid is low. 
     In addition, when at least the inflow port has the low pressure stop filter function, it is possible to provide a dripper enabling drip irrigation to be properly performed even when the liquid pressure of the irrigation liquid is low, and a drip irrigation apparatus including the dripper. In this case, the partition wall does not need to have the above-mentioned function of the diaphragm part. However, the partition wall being the diaphragm part is more effective from the viewpoint of stabilizing the drop of the irrigation liquid when the liquid pressure of the irrigation liquid fluctuates higher. 
     It is noted that the present invention is not limited to the above-described embodiment, and the above-described embodiment may be modified in various manners as long as the feature of the present invention is provided. 
     [Modification]. 
     As illustrated in  FIG. 17 , the dimension of second protrusion part  32  in the protrusion direction may be shorter, for example. 
     Alternatively, as illustrated in  FIG. 18 , second protrusion part  32  itself does not need to be provided. In this case, ejection port  3121  can be formed on second outer surface  312 . 
     Alternatively, as illustrated in  FIG. 19 , the end portion (upper end portion in  FIG. 19 ) of diaphragm part  34  on first member  2  side may be extended to such a position as to abut recess  2111 . In this case, opening  3421  for allowing the inflow of the irrigation liquid into pressure reduction channel  8  can be formed on peripheral wall part  342  of diaphragm part  34 . 
     The disclosures of Japanese Patent Applications No. 2012-196149 filed on Sep. 6, 2012, and No. 2012-216574 filed on Sep. 28, 2012 including the specification, drawings and abstract are incorporated herein by reference in their entirety. 
     Industrial Applicability 
     The dripper according to the present invention is capable of dropping a stable amount of irrigation liquid without depending on the liquid pressure of the irrigation liquid. In addition, such dripper can be formed by the joining of two injection-molded products. Therefore, it is possible to manufacture the dripper at a low cost and in a large amount. Accordingly, it is expected that the dripper and drip irrigation apparatus according to the present invention are utilized not only in drip irrigation but also in various industries where stable dropwise addition of liquid is demanded. 
     REFERENCE SIGNS LIST 
     
         
           1  Dripper 
           2  First member 
           21  First plate-like part 
           211  First inner surface 
           212  First outer surface 
           213  Pressure reduction channel part 
           22  First protrusion part 
           221  Inflow part 
           23  First guide channel 
           3  Second member 
           31  Second plate-like part 
           311  Second inner surface 
           312  Second outer surface 
           321  Ejection port 
           33  Second guide channel 
           34  Diaphragm part 
           8  Pressure reduction channel 
           11  Plate-like body