Patent Publication Number: US-2021163174-A1

Title: Fabricating method for quartz vial

Description:
TECHNICAL FIELD 
     The present invention relates to a fabricating method for a vial used for containing a chemical agent or the like. 
     BACKGROUND ART 
     A vial has a body for containing a chemical agent or the like, a bottom part closing a lower end of the body, a cylindrical neck disposed above the body, and a cylindrical mouth disposed above the neck and having an outer diameter larger than that of the neck. For the material of such vials, hard glass such as borosilicate glass has been conventionally used (See Patent Literature 1, for example). 
     Such a vial may be stored for months or sometimes years containing chemical agents or vaccines. However, in some cases where a chemical agent is stored in a vial made of hard glass for a long time, boron, sodium or the like contained in the material of the vial may elute into the chemical agent, which causes a problem in the preservation of the chemical agent. 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: JP 2012-180276 A 
     SUMMARY OF INVENTION 
     Technical Problem 
     There are many kinds of glasses including doped glass, such as the above-described hard glass, in which silicon dioxide is added with various elements, and quartz glass made of high purity silicon dioxide. The above-described problem can be solved by using quartz glass as a material of a vial. 
     In order to securely seal the vial with a cap or the like and achieve a long-term storage of contents, it is necessary to provide a precise shape on an outer peripheral surface of the neck of the vial (i.e., portion brought into contact with the cap or the like). However, it has been very difficult to make a vial having the same shape as that of the conventional vial made of hard glass from a quartz material in a large quantity and at a reduced cost by a method similar to conventional method. 
     Specifically, in a conventional vial fabricating method, outer peripheral surface of the neck and the mouth is formed into a predetermined shape by pressing a roller having a predetermined shape against the outer peripheral surface of a heated glass tube while rotating the glass tube. However, quartz glass has a softening temperature higher than that of borosilicate glass, resulting in difficulty in mass-fabricating vials with an outer peripheral surface of the neck having a precise shape in a similar method to that of the conventional vial. 
     The present invention has been accomplished in view of the above points, and an object of the present invention is to provide a method capable of fabricating numerous quartz vials having a predetermined shape. 
     Solution to Problem 
     According to a first aspect of the present invention accomplished to solve the above-described problem, a fabricating method for a quartz vial having a body for containing a substance and a cylindrical neck disposed above the body includes the steps of: forming an outer peripheral surface of the neck by shaving a quartz glass member; and joining by thermal fusion, to the neck, the body that is separately fabricated. 
     Thermal fusion according to the present invention means joining heated glasses with each other by bringing the glasses into contact with each other. The “Shaving” includes grinding, cutting, and polishing. 
     In the fabricating method for a quartz vial according to the present invention, the outer peripheral surface of the neck of the quartz vital is formed by shaving, thus enabling the quartz vial having the outer peripheral surface of the neck having a precisely predetermined shape to be fabricated. Consequently, it is possible to mass-fabricate quartz vials for long-term storage of a chemical agent or the like and having excellent sealing capability. 
     Here, in joining the body to the neck, the lower end of the body may or may not be closed by the bottom. In the latter case, after joining of the body is completed, the lower end of the body is thermally sealed, thus forming the bottom. Alternatively, a separately formed bottom may be joined to the body. 
     According to a second aspect of the present invention accomplished to solve the above-described problem, a fabricating method for a quartz vial having a body for containing a substance and a cylindrical neck disposed above the body includes the steps of: forming an outer peripheral surface of the neck by shaving a quartz glass member; and forming the body by hot working a portion of the quartz glass member adjacent to the neck. 
     Here, “hot working” means thermally softening or melting quartz glass, and then deforming the quartz glass. In the above-described fabricating method, the step of forming the outer peripheral surface of the neck and the step of forming the body may be performed in this order or in a reversed order. In the step of forming the body, the bottom closing the lower end of the body may be further formed. Alternatively, only the body may be formed first, and then, the bottom made of another quartz glass member may be joined to the body. 
     According to a third aspect of the present invention accomplished to solve the above-described problem, a fabricating method for a quartz vial having a body for containing a substance and a cylindrical neck disposed above the body includes the steps of: forming the neck by cutting a cylindrical quartz glass member; and joining by thermal fusion, to the neck, the body that is separately fabricated. 
     According to the third aspect of the present invention, the fabricating method for a quartz vial, where the quartz vial further has a cylindrical mouth disposed above the neck and having an outer diameter larger than that of the neck, further can include the steps of: forming the mouth by cutting a second quartz glass member, which is a cylindrical glass member having the same inner diameter as an inner diameter of the quartz glass member and an outer diameter larger than an outer diameter of the quartz glass member; and joining the mouth to the neck at an end opposite to an end of a side on which the body is joined. 
     Furthermore, the present invention provides a quartz vial fabricated by the fabricating method for a quartz vial according to the first or third aspect of the present invention. 
     Specifically, according to the present invention, a quartz vial having a body for containing a substance and a cylindrical neck disposed above the body includes a joined portion formed by thermally fusing quartz glasses to each other at a position between a lower end of the neck and a lower end of the body. 
     According to the present invention, the quartz vial further having a cylindrical mouth disposed above the neck and having an outer diameter larger than that of the neck can include a joined portion formed by thermally fusing quartz glasses to each other at a position between a lower end of the mouth and a lower end of the body. 
     Advantageous Effects of Invention 
     As described above, according to the fabricating method for a quartz vial according to the present invention, quartz vials having a predetermined shape can be mass-fabricated. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a side view showing the shapes of a quartz vial and a rubber plug attached to a mouth of the quartz vial according to the first aspect of the present invention. 
         FIG. 2  is a cross-sectional view of a cap that is to cover the mouth of the quartz vial. 
         FIGS. 3A-3C  are views for describing a fabricating method for the quartz vial according to the present embodiment. 
         FIGS. 4A-4B  are views for describing another example of the fabricating method for the quartz vial according to the present embodiment. 
         FIGS. 5A-5C  are views for describing a fabricating method for a quartz vial according to a second embodiment of the present invention. 
         FIG. 6  is a view for describing a fabricating method for a quartz vial according to a third embodiment of the present invention. 
         FIGS. 7A-7B  are views for describing another example of the fabricating method for the quartz vial according to the present embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Modes for carrying out the present invention will be described with reference to the attached drawings. 
     First Embodiment 
       FIG. 1  shows the configuration of a quartz vial  10  and a rubber plug  20  (a resin plug) attached to the quartz vial  10  according to a first embodiment of the present invention. The quartz vial  10  is entirely made of quartz glass, and includes a hollow body  14  for containing substances such as a chemical agent, a bottom  15  for closing the lower end of the body  14 , a cylindrical neck  13  that is disposed above the body  14 , and a cylindrical mouth  11  that is disposed above the neck  13  and has a larger outer diameter than that of the neck  13 . The body  14  further includes a cylindrical main body portion  14   a  having a constant outer diameter and inner diameter, and a reduced diameter portion  14   b  that is located above the main body portion  14   a  and has an outer diameter and inner diameter gradually decreasing upward. The outer diameter of the neck  13  is equal to the outer diameter of the uppermost end of the body  14  (i.e., the upper end of the reduced diameter portion  14   b ). Therefore, the outer diameter of the neck  13  is smaller than the outer diameter of the portion of the body  14  having the largest outer diameter (i.e., the main body portion  14   a ). Through holes having the same diameter are provided in the respective centers of the mouth  11  and the neck  13 , thus forming a passage from the upper end of the mouth  11  to the lower end of the neck  13 . The passage communicates with the inside space of the body  14 . 
     The rubber plug  20  is made of, for example, butyl rubber, and includes a plug part  21  that is inserted into the hole (i.e., the upper end of the through hole) formed at the mouth  11  of the quartz vial  10  and a disk part  22  that is brought into contact with the upper surface of the mouth  11  when the plug part  21  is inserted into the mouth  11  of the quartz vial  10 . 
     The outer diameter of the mouth  11  of the quartz vial  10  is equal to the diameter of the disk part  22  of the rubber plug  20 , and furthermore, the inner diameter of the mouth  11  (i.e., the diameter of the through hole) is equal to the outer diameter of the plug part  21  of the rubber plug  20 . 
     When the quartz vial  10  according to the present embodiment is used for storing a chemical agent or the like, the chemical agent or the like is contained in the body  14 , and then the rubber plug  20  is fitted into the mouth  11 . Furthermore, the rubber plug  20  is covered with a cap  30  ( FIG. 2 ) made of relatively soft metal such as aluminum, and the cap  30  is caulked (tightly crimped) to thus tightly close the quartz vial  10 . 
     A fabricating method for the quartz vial  10  according to the present embodiment will be explained below with reference to  FIGS. 3A-3C . First, a quartz glass member having a predetermined shape and a predetermined size is prepared, and then, is subjected to hot working or shaving (grinding by the use of a grinding wheel), thus fabricating a part obtained by integrally forming the mouth  11  and the neck  13  of the quartz vial  10  (the upper section of  FIG. 3A ). At this time, the outer peripheral surface of at least the neck  13  is formed by shaving. The inner peripheral surfaces of the mouth  11  and the neck  13  may be subjected to grinding. 
     The body  14  without a bottom is made of another quartz glass member (hereinafter referred to as a second quartz glass member) other than the above-described quartz glass member (hereinafter referred to as a first quartz glass member). The body  14  is provided with an upper opening  14   c  having the same outer diameter and the same inner diameter as those of the neck  13  (the lower section of  FIG. 3A ). The body  14  can be fabricated, for example, by using a glass tube made of quartz glass as the second quartz glass member and by narrowing the diameter of one end thereof by a drawing roller while heating the end with a burner. 
     Thereafter, the lower end of the neck  13  made of the first quartz glass member and the peripheral edge of the upper opening  14   c  of the body  14  made of the second quartz glass member are heated by the burner, and then, they are brought into contact with each other, so that the part made of the first quartz glass member and the part made of the second quartz glass member are thermally fused to each other ( FIG. 3B ). Here, the outer peripheral surface of the neck  13  has become a frosted surface, as a result of shaving and therefore, it is desirable that the frosted surface should be heated by the burner during the thermal fusion or the like to melt and smooth the surface having fine unevenness. 
     Subsequently, the lower end of the body  14  is sealed while being heated by the burner, thus forming the bottom  15  of the quartz vial  10  ( FIG. 3C ). As a consequence, the quartz vial  10  is completed as a product. 
     In  FIGS. 3A-3C , the part made of the first quartz glass member and the part made of the second quartz glass member are joined to each other in the state in which the lower end of the body  14  (i.e., an end opposite to the upper opening  14   c ) is open. However, the lower end of the body  14  may be sealed (i.e., the bottom  15  of the quartz vial  10  may be formed), before the part made of the first quartz glass member and the part made of the second quartz glass member may be joined to each other. 
     In the case where a quartz vial  40  having a conically recessed inner bottom (i.e., the upper surface of a bottom  45 ) shown in  FIG. 4B  is fabricated, a first part  46  obtained by integrally forming a mouth  41  and a neck  43 , a second part  47  serving as an upper portion  44   d  of a body  44 , and a third part  48  serving as a lower portion  44   e  of the body  44  and the bottom  45  having a conically recessed upper surface are separately fabricated, as shown in, for example,  FIG. 4A . The quartz vial  40  is fabricated by joining these three parts  46 ,  47 , and  48  by thermal fusion. The three parts  46 ,  47 , and  48  can be fabricated, for example, by hot working or by shaving respective quartz glass members. At this time, the outer peripheral surface of at least the neck  43  is formed by shaving. 
     The quartz vial fabricated by either one of the above-described methods in the present embodiment has a joined portion formed by thermally fusing the quartz glasses to each other somewhere from the lower end of the neck to the lower end of the body. The quartz vial  10  fabricated by the method shown in, for example,  FIGS. 3A-3C  has a joined portion on the boundary between the neck  13  and the body  14 . The quartz vial  40  fabricated by the method shown in, for example,  FIGS. 4A-4B  has a joined portion on the boundary between the neck  43  and the body  44 , and furthermore, a joined portion (reference numeral  44   f  in  FIG. 4B ) somewhere between the upper end and the lower end of the body  44 . 
     Second Embodiment 
     Subsequently, a fabricating method for a quartz vial according to a second embodiment of the present invention will be explained with reference to  FIGS. 5A-5C . By a fabricating method for a quartz vial  10  according to the present embodiment, the entire quartz vial is formed integrally from a single quartz glass member. Here, the shape of the quartz vial  10  that will be a product is similar to that shown in  FIG. 1 . First, a cylindrical part is made of a quartz glass member having a proper size and a proper shape by, for example, melt molding or the like. Thereafter, a mouth  11  and a neck  13  for the quartz vial  10  are formed by shaving (e.g., grinding by the use of a grinding wheel), hot working by the use of a burner, or the like ( FIG. 5A ). At this time, the outer peripheral surface of at least the neck  13  is formed by shaving. Here, a surface formed by shaving is a frosted surface, and therefore, it is desirable that the frosted surface should be heated by the burner or the like to melt and smooth the surface having fine unevenness. Subsequently, the lower end of the cylindrical part is sealed while being heated by the burner, thus forming a bottom  15  of the quartz vial  10  ( FIG. 5B ). Next, a body  14  of the quartz vial  10  is formed by increasing the inner diameter, outer diameter, and length of a portion below the neck  13  (that is, a portion adjacent to the neck  13  of the cylindrical part and opposite to the mouth  11 ) by blowing ( FIG. 5C ). As a consequence, the quartz vial  10  is completed as a product. 
     Third Embodiment 
     Subsequently, a fabricating method for a quartz vial according to a third embodiment of the present invention will be explained with reference to  FIG. 6 . Here, the shape of the quartz vial  10  fabricated by the method according to the present embodiment is similar to that shown in  FIG. 1 . 
     First, a part consisting of the mouth  11  and a part consisting of the neck  13  are separately fabricated by cutting respective quartz glass tubes. Here, the part consisting of the mouth  11  is fabricated by cutting a quartz glass tube having an inner diameter and an outer diameter respectively equal to the inner diameter and the outer diameter of the mouth  11  of the quartz vial  10  that will be a product. Here, the part consisting of the neck  13  is fabricated by cutting a quartz glass tube having an inner diameter and an outer diameter respectively equal to the inner diameter and the outer diameter of the neck  13  of the quartz vial  10  that will be a product. 
     Subsequently, these two parts are joined together by thermal fusion, and a part consisting of the body  14  and the bottom  15 , which has been fabricated separately, is thermally fused to the lower end of the neck  13 . The thus fabricated vial  10  has a joined portion formed by thermal fusion on the boundary between the mouth  11  and the neck  13  and on the boundary between the neck  13  and the body  14 . 
     Also in the present embodiment, the lower end of the body  14  may be brought into an open state (i.e., a state without a bottom) at the time when parts are joined together, and the bottom  15  may be formed by closing the lower end of the body  14  after joining the parts together is completed. 
     In the case where a vial  50  having no mouth (i.e., consisting of a neck  53 , a body  54 , and a bottom  55 ) shown in  FIG. 7B  is fabricated, a part consisting of the neck  53  is fabricated by preparing and cutting a quartz glass tube having an inner dimension and an outer dimension respectively equal to the inner dimension and the outer dimension of the neck  53  of a quartz vial  50  to be fabricated. The quartz vial  50  that will be a product is fabricated by joining, by thermal fusion, said part to a part consisting of the body  54  and the bottom  55 , which has been fabricated separately. The thus fabricated quartz vial has a joined portion formed by thermal fusion on the boundary between the neck  53  and the body  54 . Also in this case, the lower end of the body  54  may be brought into an open state (i.e., a state without a bottom) at the time when parts are joined together, and the bottom  55  may be formed by closing the lower end of the body  54  after joining the parts together is completed. 
     REFERENCE SIGNS LIST 
     
         
           10 ,  40 ,  50  . . . Quartz Vial 
           11 ,  41  . . . Mouth 
           13 ,  43 ,  53  . . . Neck 
           14 ,  44 ,  53  . . . Body 
           14   a  . . . Main Body Portion 
           14   b  . . . Reduced Diameter Portion 
           14   c  . . . Upper Opening 
           44   f  . . . Joined Portion 
           15 ,  45 ,  55  . . . Bottom 
           20  . . . Rubber Plug 
           21  . . . Plug Part 
           22  . . . Disk Part 
           30  . . . Cap