GB2197302A

GB2197302A - Sealing device

Info

Publication number: GB2197302A
Application number: GB08721025A
Authority: GB
Inventors: Yukio Tamaki
Original assignee: Sony Corp
Current assignee: Sony Corp
Priority date: 1986-09-19
Filing date: 1987-09-07
Publication date: 1988-05-18
Also published as: JPH071671B2; JPS6378431A; DE3731296A1; KR960000314B1; KR880004521A; GB8721025D0

Description

SPECIFICATION Sealing device The invention relates to a sealing device for a closed fluid containing vessel. Such a device can provide a liquid-tight or air-tight opening which can serve as an inlet or exit for a storage tank or other fluid holding vessel. An opening formed in a closed chamber such as a storage tank for liquid or gas and serving as an inlet or outlet for such liquid or gas can be closed in liquid-tight or air-tight fashion by sealing with a bonding agent of, for example, a silicone resin or by sealing with a screw. In the case of sealing with a bonding agent, there is the disadvantage that considerable time may be required for the bonding agent to dry and harden and considerable time may also be required to apply the bonding agent. There is also a restriction in the choice of materials for use as bonding agent due to a possible reaction of the bonding agent with the gas or liquid to be contained in the closed vessel. In the case of sealing with a screw, there is the problem that gas-tight or liquid-tight sealing with high reliability may be lessened or destroyed over a long period of time due to possible erosion or oxidation of the screw caused by reaction of the metal of the screw with the gas or liquid contained in the vessel. There may also be erosion of the screw due to a battery action arising from a difference in ionization tendency between the metal of the screw and the liquid or gas contained in the closed vessel. For example, a cathode ray tube projector wherein a reproduction image of a cathode ray tube is projected on a screen employs a high brightness cathode ray tube. With such a high brightness tube, the temperature of the front panel of the cathode ray tube containing the colour fluorescent screen is likely to be raised to a substantial degree because the energy of electron radiation upon the colour fluorescent screen must be high enough to produce a picture image of high brightness. This high brightness cathode ray tube exhibits the problem of radiation of X-rays from the fluorescent material on the colour fluorescent screen because of the high energy of electron radiation on the fluorescent screen. For this reason, the thickness of the front panel of the cathode ray tube must be relatively large.Consequently, the heat radiation efficiency of the front panel and hence of the fluorescent screen is low due to the fact that the heat conductivity of the glass of the front panel is relatively low. This further increases the problem of temperature rise. Also, a high temperature rise in turn raises a problem of thermal quenching of the fluorescent substances. Thermal quenching is a phenomenon wherein the brightness of fluorescent substances decreases as the temperature rises. Such thermal quenching occurs to different degrees with respect to the fluorescent substances for individual colours and consequently upon undue temperature rise an error occurs in the white balance. For this reason, a high brightness cathode ray tube requires cooling of the front panel in order to ensure good heat radiation therefrom. Various proposals have been made for circulating a coolant in the form of a transparent liquid in which convection can occur as a means for effectively cooling the front panel of such a cathode ray tube. A cooling system of kind type is described in, for example, Japanese Utility Model Publication No. 59-7731. An example of such a liquid cooled cathode ray tube is shown in Fig. 11 of the accompanying drawings, wherein cathode ray tube apparatus 1 includes a cathode ray tube 2 having a front panel 3 on which is formed a fluorescent screen 4. A transparent panel 6 is mounted in front of the cathode ray tube in opposed spaced relationship at a predetermined distance from the front panel 3 by means of an annular metal frame member 5. The metal frame member 5 has good heat radiation properties and extends along four peripheral sides of the cathode ray tube 2 so that it serves as a peripheral wall and also as a spacer. An elastic adhesive resin material 7 such as a silicone resin is interposed between the annular metal frame 5 and the front panel 3, and also between the annular metal frame member 5 and the transparent panel 6 in order to provide a liquid-tight seal between the annular metal frame member 5 and the two panels 3 and 6, thereby forming a liquid-tight closed chamber 8 between the panels 3 and 6. The closed chamber 8 is filled with a liquid coolant 9 which is introduced, for example, by means of an inlet (not shown) formed in the annular metal frame member 5. After filling up the chamber 8, the opening is closed, for example, with an adhesive resin material.The liquid coolant 9 may be a solution of ethylene glycol or similar coolant. With the construction described above, when a temperature rise occurs at a central portion of the panel 3 of the cathode ray tube 2, the coolant 9 adjacent the central portion of the panel 3 is heated, thereby decreasing its specific gravity so that it will move upwardly, causing convection currents in the coolant 9. Consequently, heat at the central portion of the panel 3 is effectively transmitted to the annular metal frame member 5 about the panel 3 and can be effectively radiated from the annular metal frame member 5. With such an arrangement as described above, undue temperature rise of the panel 3 with the fluorescent screen can be prevented effectively and, consequently, an error in the white balance of the cathode ray tube 2 due to thermal quenching can also be prevented. There is, however, the problem of expansion of the volume of liquid coolant by the temperature rise of the coolant. While in the arrangement shown in Fig. 11, the volume of the closed chamber 8 between the panel 3 and the opposed transparent panel 6 can be substantially varied by deformation or expansion of the sealing material of the elastic adhesive resin 7, such a volume expansion may still cause accidental liquid leakage and may vary or render uneven the distance between the transparent panel 6 and the front panel 3. This may raise problems of optical distortion of the projected picture image on the fluorescent screen.Where a transparent panel having a lens effect is employed as the transparent panel 6, this distortion of the projected picture image is a serious problem. Several devices have been proposed to resolve the problem of volume expansion of liquid coolant by a rise in temperature. One of the device provides an air chamber communicating with a closed chamber in which liquid coolant is contained. Such a device is disclosed, for example, in Japanese Patent Application No. 60-137037 entitled "Cathode Ray Tube Apparatus", and assigned to the applicant of this application. This arrangement, however, has the problem that the quality of the picture image may be downgraded by bubbles of air in the liquid coolant caused by vibrations of the apparatus for example during transportation. In order to eliminate such a disadvantage, it may be desirable to provide an expandable air chamber which is separated from the liquid coolant within the closed chamber 8. In that case, however, a suitable structure for air-tight or liquid-tight separation between the air chamber and the closed chamber provides a difficult design problem. According to one aspect of the invention there is provided a sealing device for a closed fluid containing vessel comprising: an elastic hollow member having a closed end and an open end with an annular flange extending outwardly at or adjacent the open end, a male or female screw member confined within the elastic hollow member, and a mating screw member threadedly engaging the screw member and able to pull the screw member towards the open end of the elastic hollow member, the hollow elastic member having a part to be inserted in an opening in a vessel with a portion of the hollow elastic member received within the vessel, the annular flange being larger in radial extent than the opening and said part of the elastic hollow member being sealable in the opening under the action of the screw member co-operating with the mating screw member. According to another aspect of the invention there is provided a sealed vessel having an opening in a wall thereof for fluid flow therethrough, said vessel being sealed with a sealing device comprising: an elastic hollow member having a closed end and an open end with an annular flange extending outwardly from the open end, a male or female screw member confined within the elastic hollow member, and a mating screw member engaging the screw member and being sufficiently large to close off the open end of the elastic hollow member, the hollow member extending through the opening in the vessel so that a portion thereof is received within the vessel and the annular flange being larger in radial extent than the opening. According to a still further aspect of the invention there is provided a cooled cathode ray tube assembly comprising a cathode ray tube having a front panel, a transparent panel located in spaced relation to the front panel and providing a closed space therebetween, frame means supporting the transparent panel and the front panel in spaced relation and having an opening therein for introducing a liquid coolant into the closed space, and a sealing device, the sealing device comprising: an elastic hollow member having a closed end and an open end with an annular flange extending outwardly at or adjacent the open end, a male or female screw member confined within the elastic hollow member, and a mating screw member threadedly engaging the screw member and being sufficiently large to close off the open end of the elastic hollow member, the hollow elastic member extending through the opening in the frame with a portion thereof received within the closed space and the annular flange being larger in radial extent than the opening.

prior art devices and can positively and simply Such a sealing device can eliminate the problems described above experienced with seal a closed chamber for containing gas or liquid without creating a possible reaction between the sealing device and the contents of the chamber. The flange extending radially outwardly from the open end can contact a peripheral portion of a wall of the vessel around the opening. Either the female screw member or the male screw member is preferably fixedly mounted in the elastic hollow member either by embedding it in the elastic member or by moulding the elastic member thereover. The mating screw member is inserted through the open end of the elastic member and is tightly engaged with the screw member. As a result of the tightening, a portion of the elastic member between the flange thereof and the location of the screw member therein is expanded annularly outwardly to present an annularly expanded portion. As a result, a portion of the elastic hollow member between the flange and the annularly expanded portion is firmly pressed against the inner wall of the opening in the vessel and the inner wall of the vessel around the opening to seal the opening against loss of gas or liquid. With the construction described, the elastic hollow member is inserted in the opening of the vessel to seal the opening liquid-tight or gas-tight. The elastic member is firmly pressed against the peripheral wall face of the opening of the vessel due to its compression by the tightening between the female screw member and the male screw member. Since the mutually engaging female and male screw members are surrounded by the elastic hollow member, they do not directly contact the contents of the closed vessel. Accordingly, in choosing a material for the screw members, any reaction between the screw members and the contents of the closed chamber or the ionization tendencies need not be taken into account so that the freedom of choice of materials is improved, while ensuring a stabilized sealing performance over a long period of time. The invention is diagrammatically illustrated by way of example in the accompanying drawings, in which: Figure 1 is a longitudinal sectional view of one embodiment of a sealing device according to the invention; Figure 2 is a longitudinal sectional view illustrating the sealing device of Fig. 1 before assembly; Figure 3 is a longitudinal sectional view showing a second embodiment of a sealing device according to the invention; Figure 4 is a longitudinal sectional view illustrating a third embodiment of a sealing device according to the invention; Figure 5 is a longitudinal sectional view illustrating the sealing device of Fig. 4 before assembly; Figure 6 is a vertical sectional view of liquid cooled cathode ray tube apparatus to which a fourth embodiment of a sealing device according to the invention has been applied;Figures 7 and 8 are longitudinal sectional views of the sealing device of Fig. 6 taken along different planes of Fig. 6; Figures 9 and 10 are longitudinal sectional views taken along different planes showing a modified form of the fourth embodiment of Figs. 7 and 8; and Figure 11 is a vertical sectional view of a liquid cooled prior art cathode ray tube to which a sealing device of previously proposed kind has been applied. Fig. 1 shows a sealing device assembled to seal an opening 101 formed in the wall of a tank 100a which defines a closed chamber 100, while Fig. 2 shows the sealing device before assembly. The sealing device shown includes an elastic air-tight or liquid-tight closed end elastic member 102a in the form of, for example, a rubber sleeve having an outer circumferential shape corresponding to the inner periphery of the opening 101 of the tank 100a.The elastic member 102a has an open end 103 at the upper part thereof and an annular flange 104 which extends integrally and radially outwardly around the circumference of the open end 103. The flange 104 has an outer peripheral dimension such that the lower face thereof can contact a portion of an outer face of the wall of the tank 100a around the opening 101. A female screw member 105a in the form of a nut is embedded in the elastic member 102a. The female screw member 105a is fixed, for example, in a coaxial relationship with the elastic member 102a and in a plane perpendicular to the longitudinal axis of the elastic member 102a. The sealing device further includes a male screw member 106a for engaging with the female screw member 105a in threaded engagement. The mate screw member 106a has a threaded portion 106a2 and a head portion 106a, which extends radially outwardly from an end of the threaded portion 106a2. The male screw member 106a is inserted into the open end 103 and engaged with the female screw member 105a located within the elastic member 102a. A lock washer 108 may be interposed between the head portion 106a, of the male screw member 106a and the flange 104 of the elastic member 102a to maintain firm tightening between the female screw member 105a and the male screw member 106a. The male screw member 106a is tightened with the female screw member 105a within the elastic member 102a. Upon such tightening, the female screw member 105a is automatically drawn-up toward the head portion 106a, of the male screw member 106a. Consequently, a portion of the circumferential wall of the elastic member 102a between the female screw member 105a and the flange 104 of the elastic member 102a is expanded annularly outwardly to form an annularly expanded portion 109. As a result, a portion of the circumferential wall between the annularly expanded portion 109 and the flange 104 of the member 102a is firmly pressed against the entire wall face of the opening 101 in the tank 100a to seal the opening 101 in a liquid tight or air-tight fashion with the elastic member 102a. It is to be noted that while the embodiment shown in Figs. 1 and 2 has a structure wherein the female screw member, i.e., the nut 105a is embedded at an intermediate depth in the elastic member 102a, the female screw member may alternatively be embedded at a bottom portion of the elastic member as shown in the second embodiment in Fig. 3. In particular, referring to Fig. 3, a female screw member 105b in the form of a nut is embedded at a bottom portion of an elastic member 102b, and a male screw member 106 is engaged and tightened with the female screw member 105b to seal the opening 101 in the same manner as described above the reference to Fig. 1. While in the first and second embodiments of the invention described above a female screw member is shown embedded in and fixed to the elastic member it is alternatively possible to embed a male screw member 106b in and fix it to an elastic member 102c. Such an alternative arrangement is illustrated in Figs. 4 and 5 wherein the male screw member 106b is shown embedded in and fixed to the elastic member 102c such that a threaded portion 106b2 thereof projects outwardly from the open end 103 of the elastic member 102c. A female screw member 105c is screwed onto and tightened with the outwardly projected threaded portion 106b2 of the male screw member 106b from outside the open end 103 so as to seal the opening 101 in an air-tight or liquid-tight manner by means of the elastic member 102c.It is to be further noted that, in Figs. 4 and 5, corresponding members or parts are identified by the same reference numerals as those in Figs. 1 and 2, and detailed description thereof is omitted to avoid repetition. A liquid cooled cathode ray tube apparatus utilizing a sealing device of the invention will be described in connection with Fig. 6. In this figure, like parts or components are denoted by the same reference numerals as those of Fig. 11, and overlapping description thereof is omitted. In the cathode ray tube apparatus shown, a first annular metal frame member 5A is mounted on and extends around four sides of a front panel 3 of a cathode ray tube 2. An adhesive resin material 7 such as a silicone resin is interposed therebetween. A second annular metal frame member 5B is mounted in front of the first annular frame metal member 5A by means of a similar adhesive material 7.A transparent panel 6 having an enlarging lens effect is secured in liquidtight relationship to a front face of the second annular metal frame member 5B by means of an adhesive resin material 7 such as a silicone resin. Thus there is formed a closed chamber 100 which can be filled with a liquid coolant 9, the chamber 100 being formed forwardly of the front panel 3 of the cathode ray tube by the annular metal frame members 5A and 5B and the transparent panel 6. An opening 101 is provided in a portion of the peripheral wall of the closed chamber 100, for example, in a portion of the annular metal frame member 5B so that the liquid coolant 9 can be poured into the closed chamber 100 therethrough. The sealing device of the present invention thus makes the opening 101 of the closed chamber liquid-tight or air-tight. The sealing device includes an elastic member 102d which defines an air chamber 200 therein to allow for expansion and contraction as the liquid coolant 9 changes in temperature. The sealing device is shown in more detail in the enlarged sectional views of Figs. 7 and 8 are taken in perpendicular planes from the arrangement shown in Fig. 6. Referring to Figs. 7 and 8, the elastic member 102d has a tubular cylindrical portion 102d, which is fitted into the opening 101 from within the closed chamber 100, and an air-chamber defining portion 102d2 is formed in integral contiguous relationship with the tubular portion 102d,. It has a depth or height and length corresponding to the closed chamber 100 so that the air chamber defining portion 102d2 may be fitted into the closed chamber 100 as seen in Fig. 6. A female screw member 105d is coaxially embedded in the tubular portion 102d, of the elastic member 102d in the same manner as described before with reference to Figs. 1 to 5. A metal ring 201 may be fitted at one end of the tubular portion 102d, of the elastic member 102d so that a male screw member 106c may be inserted into the tubular portion 102d, of the elastic member 102d through the metal ring 201 and engaged with the female screw member 105d. A washer 108 may be interposed between a head portion 106c, of the male screw member 106c and the metal ring 201.The elastic member 102d has a flange 104 formed adjacent the base end of the tubular portion 102d, such that it contacts a portion of the inner face of the wall of the tank 100a, that is, a portion of an interface of the second annular metal frame member 5B in the arrangement shown in Fig. 6, around the opening 101 over the entire periphery of the same. Accordingly, as the male screw member 106c is screwed into the female screw member 105d, the tubular portion 102d, of the elastic member 102d is contracted in its axial direction while forming an annularly outwardly expanded portion 109. A portion of the tubular portion 102d, between the annularly expanded portion 109 and the flange 104 of the elastic member 102d is firmly pressed against the circumferential wall of the opening 101 of the tank 100a to seal the opening 101 liquid-tight or air-tight with the elastic member 102d. In each of Figs. 7 and 8, the right hand half illustrates the sealing device with the male screw member 106c inserted in the female screw member 105d but not tightened completely so that the opening 101 is not sealed. The left hand half illustrates the sealing device with the male screw member 106c completely tightened within the female screw member 105d so that the opening 101 is sealed.It should be noted that in this instance, the male screw member 106c may have a though-hole formed, for example, in the axial direction therein (not shown) in order to allow the air chamber 200 to communicate with external air. On the contrary, the male screw member 106c may be solid in order to separate the air chamber 200 from external air. In either case, when the volume of a liquid coolant 9 which is in the closed chamber 100 varies as the temperature rises or falls, the air within the air chamber 200 will be compressed or expanded so that the volume of the closed chamber 100 will be adjusted in response to the variation of the volume of the liquid coolant 9. In order to promote contraction or expansion of the air chamber 200, the air chamber defining portion 102e2 of the elastic member 102e may be provided with an expansion mechanism. Referring to Figs. 9 and 10, such a modified sealing device is shown in crosssectional views taken in perpendicular planes. In Figs. 9 and 10, the right hand side half and the left hand side half illustrate the sealing device before and after assembly, respectively. The sealing device shown includes an elastic member 102e having an air chamber. The sealing device shown includes an elastic member 102e having an air chamber defining portion 102e2 in which an air chamber 200 is defined. The air chamber defining portion 102e2 has expansion means 202 such as corrugations or bellows provided therein so that the air chamber 200 may readily be expanded or contracted as the liquid coolant within the closed chamber 100 contracts or expands. In Figs. 9 and 10, like parts or elements are denoted by like reference numerals to those of Figs. 7 and 8, an overlapping description thereof is omitted. As apparent from the foregoing description, the present invention provides an elastic member which is firmly and elastically pressed against an inner peripheral wall of an opening which serves as an inlet port or outlet port for liquid or gas. Since tightening the screw means does not involve direct contact with the gas or liquid within the closed chamber, the problem of errosion caused by battery action as described above can be eliminated. The sealing device of the present invention can be used in various applications in a reliable fashion without greatly increasing the cost.

Claims

1. A sealing device for a closed fluid containing vessel comprising: an elastic hollow member having a closed end and an open end with an annular flange extending outwardly at or adjacent the open end, a male or female screw member confined within the elastic hollow member, and a mating screw member threadedly engaging the screw member and able to pull the screw member towards the open end of the elastic hollow member, the hollow elastic member having a part to be inserted in an opening in a vessel with a portion of the hollow elastic member received within the vessel, the annular flange being larger in radial extent than the opening and said part of the elastic hollow member being sealable in the opening under the action of the screw member co-operating with the mating screw member.

2. A sealing device according to claim 1, wherein the elastic hollow member is sufficiently flexible for increasing threaded engagement between the screw members to cause said part of the elastic hollow member to expand radially outwardly and sealingly engage the vessel about the periphery of the opening abutting the annular flange.

3. A sealing device according to claim 1, wherein said portion of the hollow elastic member to be received within the vessel includes expandable corrugations.

4. A sealing device according to claim 1, wherein said portion of the hollow elastic member to be received within the vessel- includes an expandable bellows.

5. A sealed vessel having an opening in a wall thereof for fluid flow therethrough, said vessel being sealed with a sealing device comprising: an elastic hollow member having a closed end and an open end with an annular flange extending outwardly from the open end, a male or female screw member confined within the elastic hollow member, and a mating screw member engaging the screw member and being sufficiently large to close off the open end of the elastic hollow member, the hollow member extending through the opening in the vessel so that a portion thereof is received within the vessel and the annular flange being larger in radial extent than the opening.

6. A sealed vessel according to claim 5, wherein the elastic hollow member is sufficiently flexible for increasing threaded engagement between the screw members to cause part of the elastic hollow member to expand radially outwardly and sealingly engage the vessel about the periphery of the opening.

7. A sealed vessel according to claim 5, wherein the portion of the hollow elastic member received within the vessel includes expandable corrugations.

8. A sealed vessel according to claim 5, wherein the portion of the hollow elastic member received within the vessel includes an expandable bellows.

9. A cooled cathode ray tube assembly comprising a cathode ray tube having a front panel, a transparent panel located in spaced relation to the front panel and providing a closed space therebetween, frame means supporting the transparent panel and the front panel in spaced relation and having an opening therein for introducing a liquid coolant into the closed space, and a sealing device, the sealing device comprising: an elastic hollow member having a closed end and an open end with an annular flange extending outwardly at or adjacent the open end, a male or female screw member confined within the elastic hollow member, and a mating screw member threadedly engaging the screw member and being sufficiently large to close off the open end of the elastic hollow member, the hollow elastic member extending through the opening in the frame with a portion thereof received within the closed space and the annular flange being larger in radial extent than the opening.

10. A sealing device for a closed fluid containing vessel substantially as hereinbefore described and illustrated with reference to the accompanying drawings.