Patent Publication Number: US-6338339-B1

Title: Pressure relief valve for an inhalator

Description:
TECHNICAL FIELD 
     The present invention relates to a valve for use in an inhalator for aerosolizing a fluid stored in a container by using high pressure gas, for example, liquefied carbon dioxide (CO 2 ) gas, as propellants, and more particularly to an improved valve adapted for restraining excessive increase in pressure within the container. 
     BACKGROUND ART 
     There is known apparatus adapted for aerosolizing a fluid such as medicine, that is stored in a container along with high pressure gas as propellant, through a valve fixed to an inlet of the container. The apparatus of this type has conventionally utilized a specific fluorocarbon (flon) as propellant. At present, the apparatus tends to use hydrofluorocarbon HFC134a as an alternative of the specific flon with increasing concern about environmental protection. However, HFC134a influences not ozonosphere but global warming not less than one thousand times the degree caused by CO 2 . Thus, if HFC134a is used with great frequency, it seems that serious environmental problem occurs. Accordingly, use of CO 2  gas or inert gases, for instance, nitrogen, helium, neon, krypton, xenon and radon, acting as aerosol propellant, is at present proposed. 
     In the case of using such gases as propellant, it is required to liquefy or compress the gases for reducing a size of container as well as the flon conventionally used. The liquefied gases have a high vapor pressure. For example, liquefied CO 2  gas has vapor pressure of 60 kgf/cm 2  at 20° C. It is also desirable that inert gases are liquefied or compressed under pressure of not less than  50 kgf/cm 2  in order to increase volumetric efficiency thereof. Japanese Patent Application First Publication No. 7-241498 discloses an aerosol using such liquefied gas. 
     The liquefied gas as propellant to be filled in the container has high vapor pressure as described above. The vapor pressure within the container tends to rapidly increase in response to even slight temperature rise of the ambient atmosphere. Therefore, such the aerosol must be handled with considerable care. 
     The above-described conventional art discloses the aerosol including a gas cartridge, a sealing plate fixed to an opening of the gas cartridge, and a gas-emitting valve mounted to the opening of the gas cartridge. Upon using the aerosol, the sealing plate is pierced by a needle connected with the valve to permit liquefied gas to be discharged from the gas cartridge through the sealing plate pierced. The sealing plate is adapted to be locally ruptured and escape the liquefied gas from the gas cartridge in response to increase in vapor pressure therewithin during storage before use. The conventional art has effects of avoiding contingencies that may be caused due to the increasing vapor pressure within the gas cartridge, whereby the gas cartridge can be safely stored. However, if the gas cartridge is used once and then vapor pressure therewithin excessively increases, the conventional art can no longer teach any effective measure. 
     It is an object of the present invention to provide a valve for use in an inhalator that is capable of relieving pressure within a container of the inhalator in response to a large increase in vapor pressure therewithin. 
     It is a further object of the present invention to provide an inhalator for aerosolizing fluid stored in a container with pressurized gas, that is capable of always restraining excessive increase in vapor pressure within the container. 
     DISCLOSURE OF INVENTION 
     According to one aspect of the present invention, there is provided a valve for an inhalator including a container having a pressurized fluid, comprising: 
     a valve case secured to the container; 
     a valve pin moveable relative to said valve case, said valve pin cooperating with said valve case to define a fluid path for discharging the pressurized fluid from the container, said valve pin having a portion extending through said valve case into the container to be exposed to the pressurized fluid; 
     a seal arranged within said valve case so as to separate said fluid path into an upstream portion communicating with inside of the container and a downstream portion communicating with outside of the container; and 
     said valve pin defining a main passage always communicating with outside of the container and a bypass passage, said valve pin having a first position where fluid communication between said main passage and said upstream portion of said fluid path is blocked to prevent the pressurized fluid from being discharged from the container and a second position where fluid communication between said upstream portion and said downstream portion of said fluid path is established through said bypass passage to permit the pressurized fluid to flow from the container; 
     a valve pin adjuster shifting said valve pin between said first position and said second position in response to change in pressure acting on said valve pin, said valve pin adjuster being mounted to said valve pin. 
     According to a further aspect of the present invention, there is provided an inhalator, comprising: 
     a container having an open end and a pressurized fluid; 
     a valve case secured to the open end of said container; 
     a valve pin moveable relative to said valve case, said valve pin cooperating with said valve case to define a fluid path through which said pressurized fluid is discharged from said container, said valve pin having a portion extending through said valve case into said container to be exposed to said pressurized fluid; 
     a seal arranged within said valve case so as to separate said fluid path into an upstream portion communicating with inside of said container and a downstream portion communicating with outside of said container; and 
     said valve pin defining a main passage always communicating with outside of said container and a bypass passage, said valve pin having a first position where fluid communication between said main passage and said upstream portion of said fluid path is blocked to prevent said pressurized fluid from being discharged from said container and a second position where fluid communication between said upstream portion and said downstream portion of said fluid path is established through said bypass passage to permit said pressurized fluid to flow from said container; 
     a valve pin adjuster shifting said valve pin between said first position and said second position in response to change in pressure within said container, said valve pin adjuster being mounted to said valve pin. 
     According to a still further aspect of the present invention, there is provided a valve for an inhalator including a container, comprising: 
     a pressurized fluid stored in the container; 
     a valve case secured to the container; 
     a valve pin moveable relative to said valve case, said valve pin cooperating with said valve case to define a fluid path through which said pressurized fluid is discharged from the container, said valve pin having a portion extending through said valve case into the container to be exposed to said pressurized fluid; 
     a seal arranged within said valve case so as to separate said fluid path into an upstream portion communicating with inside of the container and a downstream portion communicating with outside of the container; and 
     said valve pin defining a main passage always communicating with outside of the container and a bypass passage, said valve pin having a first position where fluid communication between said main passage and said upstream portion of said fluid path is blocked to prevent said pressurized fluid from being discharged from the container and a second position where fluid communication between said upstream portion and said downstream portion of said fluid path is established through said bypass passage to permit said pressurized fluid to flow from the container; 
     a valve pin adjuster shifting said valve pin between said first position and said second position in response to change in pressure acting on said valve pin, said valve pin adjuster being mounted to said valve pin. 
     According to a further aspect of the present invention, there is provided an inhalator, comprising: 
     a container having an open end; 
     a pressurized fluid stored in said container; 
     a valve case secured to the open end of said container; 
     a valve pin moveable relative to said valve case, said valve pin cooperating with said valve case to define a fluid path through which said pressurized fluid is discharged from said container; 
     a seal arranged within said valve case so as to separate said fluid path into an upstream portion communicating with inside of said container and a downstream portion communicating with outside of said container; and 
     said valve pin defining a main passage always communicating with outside of said container and a bypass passage, said valve pin having a first position where fluid communication between said main passage and said upstream portion of said fluid path is blocked to prevent said pressurized fluid from being discharged from said container and a second position where fluid communication between said upstream portion and said downstream portion of said fluid path is established through said bypass passage to permit said pressurized fluid to flow from said container; 
     a valve pin adjuster shifting said valve pin between said first position and said second position in response to change in pressure within said container, said valve pin adjuster being mounted to said valve pin. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     FIG. 1 is a section of a valve of a first embodiment according to the present invention; 
     FIG. 2 is a view similar to FIG. 1, but showing the valve placed in a position different from FIG. 1; 
     FIG. 3 is a view similar to FIGS. 1 and 2, but showing the valve placed in a position different from FIGS. 1 and 2; 
     FIG. 4 is a section of a valve of a second embodiment according to the present invention; 
     FIG. 5 is a view of a valve pin of the valve shown in FIG. 4, as viewed in a direction indicated by the arrow  5  of FIG. 4; 
     FIG. 6 is a section of a valve of a third embodiment according to the present invention; 
     FIG. 7 is a view of a valve pin of the valve shown in FIG. 6, as viewed in a direction indicated by the arrow  7  of FIG. 6; 
     FIG. 8 is a section of a valve of a fourth embodiment according to the present invention; and 
     FIG. 9 is a section of a valve of a fifth embodiment according to the present invention. 
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Referring now to FIGS. 1 to  3 , a valve  10  and an inhalator with the valve  10 , according to the present invention, are explained. 
     As illustrated in FIG. 1, the inhalator includes a container  12  having an open end  12 A that defines an aperture  12 B. The container  12  receives a fluid such as medicine, and pressurized gas acting as propellant, for instance, liquefied carbon dioxide (CO 2 ) gas or the like. The valve  10  is hermetically mounted to the open end  12 A of the container  12 . The valve  10  includes a valve case  14  secured to the open end  12 A of the container  12  and a valve pin  16  axially moveable relative to the valve case  14 . The valve case  14  has a central through bore  32  through which the vale pin  16  moves between first, second and third positions described in detail later. The valve case  14  and the valve pin  16  cooperate to define therebetween a fluid path for discharging the fluid entrained on the pressurized gas (the mixture is hereinafter referred to as merely “pressurized fluid”) from the container  12 . The fluid path allows fluid communication between inside and outside of the container  12 . The pressurized fluid is discharged from inside of the container  12  through the fluid path. The valve pin  16  extends through the valve case  14  and has one axial end, a lower end as viewed in FIG. 1, projecting inside the case  14  and an opposite axial end, an upper end as viewed in FIG. 1, projecting outside the valve case  14 . A nozzle button  18  acting as a nozzle and a pushbutton is mounted to the upper end of the valve pin  16 . The nozzle button  18  has a passage feeding the pressurized fluid from the container  12  through the valve pin  16  as explained later, and an aerosolizing outlet communicating with the passage to aerosolize the pressurized fluid therefrom. 
     Specifically, the valve case  14  is fitted into the aperture  12 B and caulked at the open end  12 A. The fluid path is disposed between an inner peripheral surface of the valve case  14  that defines the through bore  32  and an outer circumferential surface of the valve pin  16  that is opposed to the inner peripheral surface of the valve case  14 . The valve case  14  includes a case body  20  formed with a stepped bore  22  partly forming the through bore  32  and a plug  24  disposed within the stepped bore  22 . The stepped bore  22  includes a larger-diameter portion  26  exposed to the inside of the container  12 , and a smaller-diameter portion  28  connected with the larger-diameter portion  26 . The plug  24  is fitly fixed to the larger-diameter portion  26  of the stepped bore  22  and formed with an opening forming a part of the through bore  32 . The smaller-diameter portion  28  of the stepped bore  22  cooperates with the plug  24  to define an annular groove for retaining a seal  30  of a ring shape. 
     The seal  30  is fitted to the annular groove and partly projects into the through bore  32  to come into contact with the outer circumferential surface of the valve pin  16 . The seal  30  separates the fluid path into an upstream portion communicating with inside of the container  12  and a downstream portion communicating with outside of the container  12 . The seal  30  blocks the fluid path to prevent the pressurized fluid from being discharged from inside of the container  12  to outside thereof. The seal  30  is made of a suitable elastic material. 
     As illustrated in FIG. 1, the valve pin  16  includes a greater-diameter pin portion  34  partly projecting to the outside of the container  12  and a smaller-diameter pin portion  36  partly projecting into the container  12 . The smaller-diameter pin portion  36  has a predetermined length and is exposed to the pressurized fluid. 
     The valve pin  16  defines a main passage  38  for feeding the pressurized fluid to outside of the container  12 . The main passage  38  is formed in the greater-diameter pin portion  34  and always communicates with outside of the container  12  via the passage of the nozzle button  18 . The main passage  38  includes an axially extending hole  40  and a radially outwardly extending orifice  42  connected with a bottom of the axially extending hole  40 . The main passage  38  has an outlet open to the upper end face of the valve pin  16  and an inlet  43  open to the outer circumferential surface of the valve pin  16 . Namely, the axially extending hole  40  is open to the upper end face of the valve pin  16  and the orifice  42  is open to the outer circumferential surface of the valve pin  16 . The axially extending hole  40  has a relatively large diameter and the orifice  42  has a predetermined diameter smaller than the diameter of the hole  40 . The orifice  42  determines an amount of flow of the pressurized fluid to be aerosolized per unit time. Accordingly, a diameter of the orifice  42  can be suitably determined depending on a required amount of the flow of the pressurized fluid to be aerosolized per unit time. The inlet  43  defined by the orifice  42  is arranged at a predetermined portion on the outer circumferential surface of the valve pin  16  which is spaced at a predetermined distance from the outlet in the axial direction of the valve pin  16 . More specifically, the inlet  43  is located above the seal  30  and exposed to the downstream portion of the fluid path when the valve pin  16  is placed in the first position shown in FIG. 1, while the inlet  43  is located below the seal  30  and exposed to the upstream portion of the fluid path when the valve pin  16  is placed in the third position shown in FIG.  2 . 
     The valve pin has a bypass passage  62  formed on the outer circumferential surface of the greater-diameter pin portion  34  of the valve pin  16 . The bypass passage  62  is in the form of an annular groove having a V-shaped section shown in FIG.  1 . The bypass passage  62  has a width farther extending in the axial direction of the valve pin  16  than that of the seal  30 . The bypass passage  62  is arranged in a predetermined portion which is exposed to the upstream portion of the fluid path when the valve pin  16  is in the first position shown in FIG.  1  and which is substantially opposed to the seal  30  when the valve pin  16  is in the second position shown in FIG.  3 . Thus, when the valve pin  16  is in the second position, the bypass passage  62  allows fluid communication between the upstream and downstream portions of the fluid path. 
     The valve pin  16  has the first position shown in FIG. 1, in which fluid communication between the main passage  38  and the upstream portion of the fluid path is blocked to prevent the pressurized fluid from being discharged from the container  12 . In the first position, fluid communication between the bypass passage  62  and the downstream portion of the fluid path is also blocked. The fluid communication between the inside and outside of the container  12  is restrained, so that the pressurized fluid is prohibited from being discharged from the container  12  via both of the main passage  38  and the bypass passage  62 . 
     Further, the valve pin  16  has the second position shown in FIG. 3, in which the fluid communication between the upstream and downstream portions of the fluid path is established through the bypass passage  62  to permit the pressurized fluid to be discharged from the container  12 . On the other hand, in the second position, the inlet  43  of the main passage  38  is exposed to outside of the valve case  14  whereby the fluid communication between the main passage  38  and the fluid path is interrupted. The fluid communication between the inside and outside of the container  12  via the bypass passage  62  is allowed but the fluid communication therebetween via the main passage  38  is prevented. Therefore, the pressurized fluid within the container  12  is permitted to flow to outside of the container  12 . 
     The valve pin  16  also has a third position shown in FIG.  2 . The valve pin  16  is moved to the third position by depressing the nozzle button  18  toward the container  12 . In the third position, the fluid communication between the main passage  38  and the upstream portion of the fluid path is established. The fluid communication between the inside and outside of the container  12  is allowed via the main passage  38  to permit the pressurized fluid to be discharged from the container  12 . In this position, the bypass passage  62  is located fully inside the container  12  to be inactive in fluid communication between inside and outside of the container  12 . 
     The valve pin  16  is shifted by a valve pin adjuster  44  between the first and second positions in response to change in vapor pressure within the container  12  that acts on the valve pin  16 . The valve pin adjuster  44  is slidably mounted to the smaller-diameter pin portion  36  of the valve pin  16 . The valve pin adjuster  44  holds the valve pin  16  in the first position when the vapor pressure within the container  12  is less than a predetermined value and in the second position when the vapor pressure therewithin is not less than the predetermined value. 
     The valve pin adjuster  44  includes a stop  46  mounted to the valve pin  16  and a resilient member  52  acting between the valve case  14  and the lower end of the valve pin  16 . The stop  46  is fitted onto the smaller-diameter pin portion  36  of the valve pin  16  and slidable thereon in the axial direction. The resilient member  52  is in the form of a coiled spring in this embodiment. The valve pin adjuster  44  also includes a retainer  48  that supports one end of the resilient member  52  on an upper end face thereof. The retainer  48  is fixed to the lower end of the valve pin  16  by a fastening nut  50 . 
     The stop  46  includes a flange  56  supporting an opposite end of the resilient member  52  and a hollow cylindrical guide  58  that is connected with the flange  56  and guides the resilient member  52  along an outer circumferential surface thereof. The guide  58  and the resilient member  52  are disposed within the container  12  and opposed to each other on their circumferential surfaces. The stop  46  defines a communicating passage  60  always fluidly connecting the upstream portion of the fluid path with inside of the container  12 . The communicating passage  60  is formed on an upper surface of the flange  56 . 
     The stop  46  is forced by a setting load of the resilient member  52  to be in contact with a shoulder portion  54  of the valve pin  16  that is disposed between the greater-diameter pin portion  34  and the smaller-diameter pin portion  36 . Specifically, as shown in FIG. 1, an inner circumferential portion of the upper surface of the flange  56  of the stop  46  is in contact with the shoulder portion  54 . The stop  46  is thus prevented from upwardly moving relative to the valve pin  16  by the contact of the flange  56  with the shoulder portion  54 . 
     The stop  46  is forced by the vapor pressure within the container  12  to be in contact with a lower face of the valve case  14 . Namely, an outer peripheral portion of the upper surface of the flange  56  of the stop  46  is in contact with an inner peripheral portion of a lower face of the plug  24  that surrounds the opening thereof. The setting load of the resilient member  52  is set at a predetermined value greater than the vapor pressure acting on the valve pin  16  under such a normal condition that the vapor pressure within the container  12  is within a constant pressure range. Accordingly, when the vapor pressure within the container  12  is within the constant pressure range, the flange  56  of the stop  46  is urged against the lower face of the valve case  14  while it is kept in contact with the shoulder  54  of the valve pin  16 . In such a case, the valve pin  16  is held in the first position as shown in FIG.  1 . 
     The retainer  48  has a stop-limiting portion on the upper end face that is in contact with the stop  46  to limit the downward movement of the stop  46  relative to the valve pin  16  when the valve pin  16  is placed in the second position shown in FIG.  3 . Specifically, when the vapor pressure within the container  12  becomes not less than the predetermined value, the resilient member  52  is brought into a compressed state by the vapor pressure acting on the lower end of the valve pin  16  and a lower end face of retainer  48 . The valve pin  16  with the retainer  48  is moved upwardly against the biasing force of the resilient member  52  until the upper end face of the retainer  48  comes into contact with a lower end of the cylindrical guide  58  of the stop  46 . The upward movement of the valve pin  16  is thus restrained in the second position. During the upward movement of the valve pin  1   6 , the upper surface of the flange  56  of the step  46  is kept in contact with the lower face of the valve case  14 . 
     An operation of the valve  10  of the above-described first embodiment is explained hereinafter. 
     When the nozzle button  18  is in a non-depressed position shown in FIG. 1, under condition that the vapor pressure within the container  12  is within the predetermined range, the valve pin  16  is held by the valve pin adjuster  44  in a normal position, i.e., the first position shown in FIG.  1 . In this case, the inlet  43  of the main passage  38 , i.e., the opening of the orifice  42 , is located downstream of the seal  30  contacted with the outer circumferential surface of the valve pin  16 . The main passage  38  is prevented from fluidly communicating with the upstream portion of the fluid path and then inside of the container  12 . On the other hand, the bypass passage  62  is located upstream of the seal  30  and inactive in fluid communication with the upstream and downstream portions of the fluid path. As a result, the pressurized fluid within the container  12  is prevented from flowing therefrom through the main passage  38  and the bypass passage  62 . 
     When the nozzle button  18  is depressed, the valve pin  16  is displaced into the third position shown in FIG.  2 . At this time, the inlet  43  of the main passage  38  is located upstream of the seal  30  contacted with the outer circumferential surface of the valve pin  16 . The main passage  38  is in fluid communication with the upstream portion of the fluid path and the inside of the container  12 . Thus, the pressurized fluid within the container  12  is discharged from the container  12  through the main passage  38  and the aerosolizing outlet of the nozzle button  18 . 
     When the vapor pressure within the container  12  becomes not less than the predetermined value due to increase in atmospheric temperature under condition that the nozzle button  18  is in the non-depressed position, the pressure force acting on the valve pin  16  becomes greater than the biasing force of the resilient member  52  to thereby deform the resilient member  52  to the compressed state. When the resilient member  52  is compressedly deformed by a predetermined degree, the retainer  48  comes into contact with the cylindrical guide  58  of the stop  46  and the valve pin  16  is placed in the second position shown in FIG.  3 . In this condition, the bypass passage  62  of the valve pin  16  is opposed to the seal  30  and active to establish fluid communication between the upstream  80  and downstream  81  portions of the fluid path. The inside of the container  12  is in fluid communication with the outside thereof via the bypass passage  62 , whereby the vapor pressure exceeding the predetermined value is relieved from the container  12 . Thus, the vapor pressure within the container  12  is reduced. 
     When the vapor pressure within the container  12  decreases to a value less than the predetermined value, the valve pin  16  is moved back to the first position shown in FIG. 1, by the restoring force of the resilient member  52 . The fluid communication between the upstream and downstream portions of the fluid path is blocked again by the hermetic contact of the seal  30  with the outer circumferential surface of the valve pin  16 . The relief of the vapor pressure within the container  12  is thus prohibited. 
     As explained above, the valve  10  and the inhalator with the valve  10 , according to the present invention, have a simple structure and assures avoiding contingencies that may be caused due to the excessive increase in vapor pressure within the container  12 . Namely, the valve pin adjuster  44  allows the fluid communication between the inside and outside of the container  12  through the bypass passage  62  of the valve pin  16  in response to increase in vapor pressure within the container  12  to the predetermined value. 
     Further, if the vapor pressure within the container  12  is relieved therefrom once, the valve pin  16  can be returned to the normal first position by the restoring force of the resilient member  52 . Accordingly, even if the vapor pressure within the container  12  increases to not less than the predetermined value again after the return of the valve pin  16  to the normal first position, the valve pin  16  can be displaced into the second position in response to the increase in vapor pressure within the container  12 . Therefore, the vapor pressure can be relieved from the container  12  via the bypass passage  62  so that the vapor pressure within the container  12  can decrease to below the predetermined value. Thus, the inhalator can always restrain excessive increase in vapor pressure within the container  12 . 
     Furthermore, with the arrangement of the communicating passage  60  on the flange  56  of the stop  46 , the inside of the container  12  always communicates with the upstream portion of the fluid path. The fluid communication between them is advantageous in securing a relief passage for relieving vapor pressure within the container  12  without being interrupted by the resilient member  52  upon the vapor pressure within the container  12  increasing. 
     Referring to FIGS. 4 to  9 , valves  100 ,  200 ,  300  and  400  of second, third, fourth and fifth embodiments according to the present invention are explained hereinafter, which differ in arrangement of the bypass passage of the valve pin from the valve  10  of the above-described first embodiment. Like reference numerals denote like parts and therefore detailed explanations therefor are omitted. 
     FIGS. 4 and 5 show the valve  100  of the second embodiment, in which the bypass passage  162  is in the form of a round cutout formed on a predetermined portion on the outer circumferential surface of the valve pin  16 . The bypass passage  162  has an arcuate section taken along the axial direction of the valve pin  16  as shown in FIG.  4 . The bypass passage  162  is partly defined by opposed peripheral edges shown in FIG. 5, that lie in parallel planes perpendicular to the axial direction of the valve pin  16 . 
     FIGS. 6 and 7 show the valve  200  of the third embodiment. As illustrated in FIG. 6, the bypass passage  262  is in the form of substantially a half-round key way-shaped cutout, which is formed on a predetermined portion on the outer circumferential surface of the valve pin  16 . The bypass passage  262  has a rectangular shape in a front view as shown in FIG.  7 . The bypass passage  262  is defined by opposed peripheral edges lying in parallel planes perpendicular to the axial direction of the valve pin  16 . 
     In both of the second and third embodiments, the cutouts as the bypass passages  162  and  262  are arranged on the predetermined portions on the outer circumferential surface of the valve pin  16 , respectively. With this arrangement, the formation of the bypass passages  162  and  262  can be facilitated as compared with the bypass passage  62  of the first embodiment that is formed of the annular groove and therefore the manufacturing cost can be reduced. 
     FIG. 8 shows the valve  300  of the fourth embodiment, in which the bypass passage  362  is in the form of a through hole having a generally V shape as indicated by a phantom line. The bypass passage  362  has openings on the outer circumferential surface of the valve pin  16  that are spaced from each other in the axial direction of the valve pin  16 . 
     FIG. 9 shows the valve  400  of the fifth embodiment, in which the bypass passage  462  is in the form of a straight and inclined through hole as indicated by a phantom line. The bypass passage  462  extends inclining relative to the axial direction of the valve pin  16  and has openings on the outer circumferential surface of the valve pin  16  that are spaced from each other in the axial direction of the valve pin  16 . 
     In the fourth and fifth embodiments, the openings of the bypass passages  362  and  462  that are open to the outer circumferential surface of the valve pin  16  have smaller areas than the opening of the bypass passage  62  formed into the annular groove in the first embodiment. Therefore, upon displacement of the valve pin  16 , butting of the seal  30  against the periphery of the openings of the bypass passages  362  and  462  can be alleviated. As a result, the seal  30  can be prevented from being heavily deteriorated by duration of use, so that the durability of the seal  30  can be improved. 
     INDUSTRIAL APPLICABILITY 
     As described above, the valve of the present invention is useful in relieving vapor pressure from a container storing pressurized fluid, in response to the vapor pressure within the container becoming not less than the predetermined value. The valve is applicable to apparatus, such as inhalator, sprayer and the like, including a container storing fluid along with pressurized gas as propellant. Further, the inhalator of the present invention is useful in always avoiding excessive increase in vapor pressure within a container that stores fluid along with pressurized gas. The inhalator of the present invention is generally applicable to inhalators using pressurized gas as aerosol propellant.