[0001] This invention relates to a sealing plug and, more particularly, to a sealing plug
for sealing the opening of a vessel such as a test tube or a beaker to block air or
water flow between the inside and outside of the vessel.
[0002] Heretofore, sealing plugs for sealing the opening of such vessels as test tubes,
flasks, beakers and and so forth used for scientific experiments are generally made
of cork, which occurs naturally, light in weight and very elastic.
[0003] However, since cork occurs naturally, its production is limited. In addition, with
the progress of techniques of synthesis and method of mass production and also versatile
needs for chemical stability and so forth, other materials than cork such as rubber,
synthetic rubber, glass and polymers, e.g., vinyl chloride, nylon, silicone, are gradually
extensively used for the sealing plug.
[0004] However, such polymer sealing plugs are heavy in weight and inconveniently require
great labor in daily handling and transportation.
[0005] Besides, these heavy polymer materials are inferior in processibility. Fig. 3 shows
a prior art sealing plug 2 for sealing an opening 1a of a vessel 1. As is shown, the
plug 2 should be formed with bores 2, through which glass tubes 6 are inserted to
transfer liquid W contained in the vessel 1 to the outside. It is, however, considerably
difficult to form the bores 6.
[0006] Further, polymers, including silicone, are considerably expensive, leading to high
cost of the sealing plug.
[0007] This invention seeks to solve the above problems.
[0008] According to the invention, there is provided a sealing plug for sealing the opening
of a vessel to block air and water, which sealing plug is made of rubber or polymer
foam having numerous independent pores.
[0009] In the above construction, the numerous independent pores of the sealing plug have
an effect of blocking flow of air or water owing to their own independency.
[0010] Further, since air in each of the numerous independent pores has very small specific
gravity, the sealing plug itself can be light in weight.
[0011] Furthermore, the independent pores permit the sealing plug to be flexibly fitted
to the size and shape of the opening of the vessel owing to the elasticity of themselves
and their contained air. The sealing plug thus can seal the vessel in close contact
therewith and by filling even very slight gaps with the vessel opening.
Fig. 1 is a perspective view showing an embodiment of the invention;
Fig. 2 is a view for explaining the processibility of the same embodiment; and
Fig. 3 is a view showing a prior art sealing plug.
[0012] Now, a preferred embodiment of the invention will be described in conjunction with
the constitution and function thereof with reference to the drawings.
[0013] Fig. 1 is a perspective view showing an embodiment of the invention. In the Figure,
reference numeral 1 designates a glass vessel. An opening 1a of the glass vessel 1
is sealed with a sealing plug 2.
[0014] The sealing plug 2 has a tapered perhpheral surface 3 with the diameter reduced toward
the front end so that it can be readily inserted into the opening 1a.
[0015] The sealing plug 2 is made of a synthetic rubber or polymer material. This material
is foamed to form numerous independent pores 4.
[0016] Since the pores 4 are independent of one another, air in a pore can not be moved
to other pores. The sealing plug 2 thus does not permit passage of air or water, that
is, it has a sealing property.
[0017] Therefore, the sealing plug 2 can be effectively used to seal a vessel for culturing
anaerobic bacteria for it can block air.
[0018] Further, since air having very low specific gravity is in the pores and the sealing
plug 2 having numerous independent pores 4 contains considerable air in the inside,
although the sealing plug 2 is made of synthetic rubber or polymer material which
is heavy in weight, it may be very light in weight for it has numerous independent
pores.
[0019] Thus, the light-weight sealing plug 2 requires small labor at the time of its transportation
and can be handled conveniently.
[0020] Further, since air is sealed in each of the independent pores 4, it is possible to
produce a sponge-like soft sealing plug by making use of the elasticity and cushioning
property of the sealed air.
[0021] Thus, the soft sealing plug 2 has extended adaptability with respect to the shape
and size of the opening 1a of the vessel. It can softly fit itself to the vessel opening
even where the slope of the taper 3 is made slightly sharper. It can seal the opening
1a of the vessel 1 in close contact therewith without any gap formed therewith.
[0022] By making use of the extended adaptability of the manufacture and storage of the
sealing plug 2 can be readily controlled by simplifying the size and shape standards
of the sealing plug 2 fn the prior art.
[0023] Further, since the sealing plug 2 has numerous independent pores 4 formed by foaming
rubber or polymer material, actually it consists of its material and air and has
a reduced material density, so that its processing can be facilitated.
[0024] For this reason, the sealing plug 2 may be readily formed with bores 6 for mounting
pipes 5 therein as shown in Fig. 2.
[0025] Further, since the material density is reduced by the foaming, sealing plug 2 using
silicone or like expensive material requires comparatively low material expenditures,
thus permitting cost reduction.
[0026] As has been described in the foregoing, the sealing plug according to the invention
has numerous independent pores formed by foaming rubber or polymer material, it is
possible to maintain the function of sealing the vessel.
[0027] In addition, since the sealing plug can be made lighter in weight with numerous independent
pores, its transportation and other handling can be facilitated and carried out more
conveniently.
[0028] Further, since the sealing plug has rich elasticity because of its numerous independent
pores, it has extended adaptability with respect to the size and shape of the vessel
opening, and the manufacture and storage of sealing plugs can be controlled more easily
by simplifying the size and shape standards.
[0029] In addition, since the sealing plug is formed by foaming rubber or polymer material,
it can be more readily machined to form, for instance, bores for passing glass pipes.
[0030] Furthermore, since the sealing plug is formed by foaming rubber or polymer, it requires
a reduced amount of material, so that its cost can be reduced.