VALVE WITH RESIDUAL PRESSURE INDICATOR FOR PORTABLE OXYGEN INHALANT CYLINDER

Abstract: A valve (3) is secured to a mouth (2) of a portable gas cylinder (1) containing pressurized oxygen. A residual pressure indicator (13) is assembled within the valve casing (6) and is observable from outside the valve casing. The indicator includes a piston 28 extending lengthwise of the valve casing.

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve with a residual pressure indicator for a portable oxygen inhalant cylinder, which is provided for an oxygen inhalant cylinder brought out by a patient who has pulmonary disease or respiratory disease or carried by a doctor or rescuers at a rescue operation, and of which valve casing is provided with a residual pressure indicator at the lower half thereof which indicates a residual oxygen pressure in the cylinder( inner volume: ab. 3 l ). 2. Prior Art Recently, thanks to a medical progress is gradually increasing the number of patients who go out with the aid of an oxygen walker even though such patients always need the oxygen inhalants due to their pulmonary disease or respiratory disease. In case that the oxygen in the cylinder is emptied during their outing or such rescue dispatching, such patients get into difficulty in breathing and get encountered to a fatal danger. Therefore, in order to prevent such dangerous situations, it is especially directed very often and enforced that the sufficient amount of residual oxygen in the cylinder is confirmed by means of the residual pressure indicator before outing. A valve with a residual pressure indicator for a portable oxygen inhalant cylinder according to the present invention has a basic construction, for example as shown in Fig.1 or in Fig.7. That is, in an upper half of a valve casing 6, there is provided a valve chamber 8 which has an inlet port 9 opened at the bottom surface of the casing 6 as well as an outlet port 10 opened at the side surface thereof and also has a valve body 11 put therein. At the upper side of the valve casing 6, there is provided a handle 12 which is used for opening and closing the valve body 11, and at the lower half of the valve casing 6, there is provided a residual pressure indicator 13 for an oxygen cylinder. As for a construction for setting up the residual pressure indicator to the valve on premising that basic construction, so far has been known the conventional first embodiment as shown in Fig.7. In this embodiment, a residual pressure conduction port 50 is transversely branched off from the intermediate portion of the inlet port 9 and opened at the lower half side surface of the valve casing 6. And to the outer end portion of the residual pressure conduction port 50, a Bourdon tube pressure gauge 51 is fixedly connected in communication by means of its foot screw 51a. Besides the oxygen inhalant application and the premised construction as described above, the conventional second embodiment as shown in Figs.8 and 9 has so far been put on the market as a valve provided with a primary pressure indicator in a pressure reduction valve which is detachably connected to a liquefied carbon dioxide container for a draught beer feeder. Fig.8 is a plan view of the pressure reduction valve 53, in which carbon dioxide gas in the container 54 is induced to a primary pressure inlet 53a from the container valve 55 while the primary pressure is indicated by the primary pressure indicator 56, then reduced in pressure within a pressure reduction valve body 57 and discharged from a secondary pressure outlet 53b while the secondary pressure is indicated by a secondary pressure indicator 58. Fig.9 is a vertical sectional view of the primary pressure indicator 56 of an air pressure operational cylinder type which has a pressure receiving piston counterbalanced by a balance spring. It is fixedly secured to the side surface of the pressure reduction valve body 57 so as to project laterally by means of screws. When the primary pressure is transmitted to a cylinder chamber 59 through a primary pressure discharge port 57a and the pressure in a container 54 gets a fully charged pressure, the piston actuates a residual pressure indicating rod 61 so as to project a residual pressure indicating ring 62 thereof to a large distance outside a cover 63. As the residual pressure gets decreased, the indicating ring 62 is shifted toward the cover 63 by the balance spring 64. When the residual pressure in the container has decreased to ab. 20 Kg/cm² , the indicating ring 62 enters within the cover and gets concealed therein. Further, in spite of a different field from the third embodiment has so far been known a valve disclosed in US Patent No. 4,580,450 by the assignee of the present invention. As shown in Fig.10, in the side wall of a valve casing 71 of a high pressure valve 70 for a vertical elongated cylindrical container C for liquefied carbone dioxide, there is provided a vertical guide hole 72 formed as a blind hole upwardly from the lower surface 73 of the valve casing 71 over the whole of its height. In this guide hole 72, there is provided a residual quantity detecting means 74 movably in the vertical direction. The detecting means is connected to an elongate cylindrical float 76 through a rod 75. The float 76 is received in the container C movably in the vertical direction. The rod 75 is biassed downwardly by an extension spring 77 held by the valve casing 71. At the level corresponding to the residual quantity detecting means 74 outside the peripheral wall of the guide hole 72, there is provided a residual quantity indicating means 78 so as to indicate a residual quantity of liquefied carbon dioxide in the container C. The indicating means 78 is adapted to be moved vertically by the detecting means 78 through magnetic force so that the liquid level in the liquefied carbon dioxide container C can be confirmed visually with the residual quantity indicating means 78. The conventional first embodiment shown in Fig.7 has for its advantages large pressure-resistance as well as high accuracy for indicating a residual pressure because the residual pressure in the container is detected by a deformation of a Bourdon tube under pressure, but has for its disadvantages following problems. (a) The Bourdon tube pressure gauge 51 has a magnifying mechanism of a gear type for magnifying a very small displacement caused by a deformation of a Bourdon tube under pressure, which serves to drive a pointer on a graduated plate in a magnified manner by making use of a pinion having fine teeth. Further, since the Bourdon tube pressure gauge 51 is small enough to be used for the small portable oxygen inhalant container 1 correspondingly, the teeth of the pinion becomes finer and weaker against a shock as the result. In case that the teeth of the pinion gets damaged when the pressure gauge 51 is shocked by its falling down or its collision with other objects, the pointer is apt to be locked. Thus, in the case of using it without noticing such trouble, the pointer is kept indicating a high pressure even though a residual pressure in the container has decreased to a large extent. As the result, in spite of the confirmation of an enough residual pressure of oxygen by the patient before outing, it is apprehended that the patient gets into a fatal danger because the oxygen is almost exhausted during outing. (b) Since the Bourdon tube pressure gauge 51 is secured to the valve casing 6 in an outward projecting manner, it is apt to be broken by a shock caused by its falling down or its collision with other objects. In such a case, it is also apprehended that the patient gets into a fatal danger because the oxygen escapes completely from the container through the breakage portion. Even though the patient gets out of such danger, the Bourdon tube pressure gauge 51 is always in danger of breakage by collision with other objects because it projects outside the valve casing 6. The Bourdon tube pressure gauge 51 of the conventional first embodiment as shown in Fig.7 can be replaced with the primary pressure indicating means 56 of the conventional second embodiment 2 as shown in Figs.8 and 9. In the combined construction of these first and second conventional embodiments, since it is adapted to transmit the movement of the piston 60 directly to the residual pressure indicating rod 61, it has such advantage as the above-mentioned problem (a) can be solved. However, it still has the problem (b) as well as the following problems. Even though the residual pressure indicating ring 62 indicates ab. 20 Kg/cm² at the position near the entrance of the cover 63, it is still difficult to know a residual pressure in the container when the ring 62 is outside the cover or within the cover 63. On the other hand, the third conventional embodiment is applied to a relatively large container C for liquefied carbon dioxide in an entirely different field from the present invention. And since the residual quantity indicating means is adapted to be moved correspondingly by the vertical movement of the float 76, it can't be applied to the small-sized light gas cylinder which is charged with compressed oxygen for an oxygen inhalation. Further, also in this third conventional embodiment, since the residual quantity indicating means 78 is attached to the valve casing 71 in an outwardly projecting manner, it is impossible to avoid the risk of the breakages of the indicating means 78 by its falling down or by its collision with other objects. It is known from EP-A-0183263 to provide a valve assembly for use with a portable gas cylinder and comprising an elongate valve casing adapted for fitment within a mouth of the cylinder, an inlet port extending through the casing to a valve chamber including a valve member operable to allow and prevent gaseous flow from the cylinder through the chamber to an outlet port, and a residual pressure indicator. Claim 1 of the present application is delineated over this document. The present invention is characterised in that the residual pressure indicator comprises an elongate piston supported for lengthwise movement in a chamber formed separately from the inlet port and extending lengthwise within said casing, and an indicator disposed within a recess in the casing and constituted by a part of the piston or movable in response to movement of the piston. An advantage of such a valve assembly is to provide a valve with a residual pressure indicator for a portable oxygen inhalant cylinder which is able to accurately indicate a residual pressure within a gas cylinder by improving the vibration proof performance as well as the shockproof performance of the residual pressure indicator. It is another advantage of the present invention to provide a valve with a residual pressure indicator for such a cylinder which is able to prevent breakage or damage of the residual pressure indicator which might be caused by a collision with other objects. It is a further advantage to provide such a valve which is able to indicate an accurate residual pressure within a gas cylinder over a wide range from a high pressure to a low pressure. Preferably a residual pressure measuring chamber is provided vertically at the portion beside the inlet port in the lower half of the valve casing, a through hole for a pressure actuator bar is opened downwardly from the lower end portion of the residual pressure measuring chamber, a sealing means is provided at the through hole so as to contact with the intermediate portion of the pressure actuator bar and permit the vertical sliding movement thereof, a balancing spring is connected to the lower portion of the pressure actuator bar so as to elastically force the bar downwardly, and a residual pressure indicating means is provided onto the pressure actuator bar so as to move vertically within the residual pressure measuring chamber. According to the present invention, as shown in Fig.1, the pressure actuator bar is moved upwardly within the through hole against the elastic force of the balancing spring under a high residual pressure condition within the oxygen inhalant cylinder, and the residual pressure indicating means is shifted to an upper position within the residual pressure measuring chamber. Accordingly, a much amount of residual oxygen within the cylinder can be confirmed by observing the level of the indicating means through a peep window. On the other hand, as the residual pressure is decreasing due to a consumption of oxygen within the cylinder, the elastic force of the balancing spring exceeds the pressure force acting on the pressure actuator bar and moves the bar downwardly so as to shift the residual pressure indicating means to a lower position in the residual pressure measuring chamber. A less amount of residual oxygen within the cylinder is confirmed by observing the indicating means shifted lower than a predetermined level through the peep window. The foregoing and other advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered by the accompanying drawings, wherein: BRIEF DESCRIPTION OF THE DRAWINGS Figures 1 through 6 show the embodiments of the present invention; Figures 1 through 4 show the first embodiment thereof; Figure 1 is vertical sectional view showing a valve with a residual pressure indicator for a portable oxygen inhalant cylinder; Figure 2 is an exploded perspective view of an oxygen inhalant device; Figure 3 is an enlarged view of a principal part in Fig.1; Figure 4 is a sectional view on line IV-IV in Fig.3; Figures 5 and 6 show the second embodiment of the present invention; Figure 5 is a view corresponding to Fig.3; Figure 6 is a sectional view on line VI-Vi in Fig.5; Figures 7 through 10 show conventional embodiments; Figure 7 is a sectional view of the first embodiment thereof; Figures 8 and 9 show the second embodiment thereof; Figure 8 is a plan view thereof; Figure 9 is a sectional view on line IX-IX in Fig.8; and Figure 10 is a sectional view of a principal part of the third embodiment. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Now the preferred embodiments of the present invention will be described with reference to the drawings hereinafter. < First Embodiment > Figs. 1 through 4 show the first embodiment. Fig. 2 is an exploded perspective view of a portable oxygen inhalant device A. Referring to Figs. 1 and 2, a valve 3 is fixedly secured to an inlet 2 of an oxygen inhalant cylinder 1, and an oxygen taking out means 4 is adapted to be connected to the valve 3. The oxygen inhalant device A is of a size to be carried out with a portable case( not shown in Figs. ), and to be utilized for an aid of inhalation by a patient who has pulmonary disease or respiratory disease so that the oxygen charged into the cylinder 1 can be taken out through the valve 3 and the oxygen taking out means 4. First of all, mainly the valve 3 will be explained with reference to Fig. 1. The valve 3 has a valve casing 6 which is rectangular in a plan view, a foot portion 7 which is fixedly screwed into a threaded hole 2a provided at the inlet 2 of the oxygen inhalant cylinder 1 and a flange 6a which is formed at the lower portion of the valve casing 6 and is abutted onto the upper surface of the inlet 2 gas-tightly. In the upper half of the valve casing 6, there is formed a cylindrical valve chamber 8 of which inlet port 9 is opened at the bottom surface of the foot portion 7 and of which outlet port 10 is at the right side surface of valve casing 6. In the valve chamber 8, there is provided a valve body 11 vertically adjustably which is engaged with a handle 12 provided at the upper portion of the valve casing so as to open or close the valve body 11. At the lower half of the valve casing 6, there is provided a residual pressure indicator 13 which indicates a residual pressure of oxygen within the cylinder 1. And at the right side of the valve casing 6, there is provided a safety valve 14 of a thin plate type which is fixed by a screw plug. !4a is a thin plate for explosion. Now the oxygen taking out means 4 will be explained with reference to Fig. 2 hereinafter. The oxygen taking out means 4 is of a well known type, and is provided with a pressure regulator 15 and a flow meter 16, and is connected to the valve casing 6 of the valve 3 through a box-shaped mount frame 17 which is standardized in dimension. That is, the mount frame 17 is fitted to the upper half of the valve casing 6 and an inlet nozzle 15a of the pressure regulator 15 is inserted into the outlet port 10 of the valve 3, And then a tightening bolt 18 engaged with the mount frame 17 is inserted into a hole 6a for positioning at the left side of the valve casing 6 and tightened so that the nozzle 15a of the pressure regulator 15 can be fixedly pushed to the outlet port 10 of the valve 3. The oxygen is adapted to be supplied from an outlet nozzle 16a provided at the lower side of the flow meter 16. By the way, at a position below the inlet nozzle 15a in the mount frame 17, there is provided an engage pin( not shown in Figs. ) for positioning which is adapted to be engaged to an engage hole 6b formed at the right side of the valve casing 6 when the mount frame 17 is connected. The dimension and the number of engaging portions between the hole 6b and the pin are determined different according to the kind of gas so that a different kind of gas can't be taken out. Now the residual pressure indicator 13 provided on the valve 3 as a subject-matter of the invention will be explained mainly with reference to Figs. 3 and 4 hereinafter. At a different position within the lower half of the valve casing 6 from the inlet port 9, there is formed a cylindrical residual pressure measuring chamber 20 vertically. In the peripheral wall 21 of the residual pressure measuring chamber 20, there is provided a peep window 22. A transparent resin tube 23 is put in the chamber 20 and provided with a cushion member 25 at the upper and the lower ends thereof respectively. The transparent tube 23 is fixedly pushed to the valve casing 6 by a holder 24 which forms the bottom wall of the chamber 20. The holder 24 is mounted to the foot portion 7 by threaded portions gas-tightly through an O-ring 26. In the holder 24, there is provided a through hole 29 which is provided with a sealing means 30 of O-ring through which the pressure actuator bar 28 is passed vertically slidably and gas-tightly at the intermediate portion 28a thereof. A balancing spring 31 for a residual pressure measurement is connected to the lower portion of the pressure actuator bar 28 so as to elastically force the bar 28 downwardly and accommodated within a spring support sleeve 32 which is fixedly screwed in the lower portion of the holder 24. The balancing spring 31 is composed of an extension coil spring, supported at its lower end by a pin 33 provided at the lower end of the sleeve 32 as well as connected at its upper end to the lower portion 28b of the spring actuator bar 28. And at the upper portion 28c of the pressure actuator bar 28, there is provided a residual pressure indicating means 34, which is vertically movable within the transparent tube 23 with the pressure actuator bar 28 and of which level is capable of being observed through the peep window 22. At the upper end surface of the holder 24, there is provided a notch 36, through which the interior of the transparent tube 23 is communicated to the open air. Besides, in order to obtain the communicating means for communicating the interior of the transparent tube 23 to the open air, at least one of the upper and the lower cushion members 25, 25 may be made porous ventilatively. Accordingly, even though the oxygen within the cylinder 1 enters into the tube 23 by permeating through the O-ring 26 fitted around the periphery of the holder 24 and/or the O-ring 30 fitted around the inner periphery thereof, the pressure increase within the tube 23 can be avoided. And the transparent tube 23 has graduations( not shown in Figs.) for indicating a residual pressure in the vertical direction. By the way, in the above-mentioned first embodiment, instead of the transparent tube 23 and the cushion member 25, 25 in the residual pressure measuring chamber 20, the residual pressure indicating means 34 within the chamber 20 may be adapted to be observed directly through the peep window 22. In this case, the graduations can be provided at the inner periphery 21 of the chamber 20 in the vertical direction thereof. Further, instead of the extension spring, a compression spring can be used for the balancing spring 31 because it is enough for the balancing spring 31 only to elastically force the pressure actuator bar 28 downwardly. According to the present first embodiment, since the balancing spring 31 is provided in the space below the valve casing 6, it is accommodated within the cylinder in the case that the valve 3 is fixedly secured to the cylinder 1. Therefore, the inner space within the cylinder 1 can be utilized so effectively that the height of the valve casing 6 is prevented from being increased even in the case of the provision of the balancing spring 31. Further, in the first embodiment, the box-shaped mount frame 17 is used for the connecting means to connect the pressure regulator 15 to the valve 3. But, instead of that, a direct connection by means of thread can be adopted as for the connecting means. < Second Embodiment > Figs. 5 and 6 show the second embodiment. A structure different from that in the first embodiment will be explained hereinafter. In this embodiment, instead of the above-mentioned peep window 22, a concavity 40 is formed at the peripheral wall 21 of the valve casing 6 so as to be arranged adjacent to the residual pressure measuring chamber 20, and a transparent tube 42 is disposed in the concavity 40 to provide a residual pressure indicating chamber 41 within the tube 42. The transparent tube 42 is provided with an upper end piece 43 and a lower end piece 43 respectively and secured to the concavity by a screw 44 through the end pieces 43, 43. And within the transparent tube 42 there is provided a cylindrical indicating piece 45 which is vertically movable by means of magnetic force. On the other hand, a residual pressure indicating means 34 is provided on an upper portion 28c of a pressure actuator bar 28 and formed in a cylindrical configuration. One of or both of the residual pressure indicating means 34 and the residual pressure indicating piece 45 are composed of a magnet so that the piece 45 can be moved vertically within the transparent tube 42 following the vertical movement of the means 45. Accordingly, since the present invention is constructed and functions as described above, the following advantages can be obtained. (a) Since the pressure actuator bar which actuates the residual pressure indicating means is simply constructed so as to move vertically linearly slidably, the vibration-proof and the shock-proof thereof are greatly improved. In a conventional Bourdon tube pressure gauge, a pointer happens to be locked by a damage of a pinion in a gear type magnifying mechanism when being shocked or vibrated. According to the present invention, such problems can be solved and always an residual pressure in the gas cylinder can be indicated accurately. (b) Since the components such as the pressure actuator bar and the residual pressure indicating means etc are accommodated within the valve casing, they are protected thereby against collisions with other objects. Therefore, the indicator can be prevented from being broken or damaged by a falling down of the gas cylinder or a collision with other objects. (c) Since the residual pressure within the gas cylinder is adapted to be indicated by the level of the residual pressure indicating means( or by the residual pressure indicating piece ) and the level thereof is adapted to be observed readily from an outside of the valve casing, it can be confirmed over a wide range from a high pressure to a low pressure.

Claims: A valve assembly for use with a portable gas cylinder and comprising an elongate valve casing (6) adapted for fitment within a mouth (2) of the cylinder, an inlet port (9) extending through the casing to a valve chamber (8) including a valve member (11) operable to allow and prevent gaseous flow from the cylinder through the chamber to an outer port (10), and a residual pressure indicator, characterised in that the residual pressure indicator comprises an elongate piston (28) supported for lengthwise movement in a chamber (20) formed separately from the inlet port and extending lengthwise within said casing, and an indicator (34,45) disposed within a recess (22,40) in the casing and constituted by a part of the piston or movable in response to movement of the piston. A valve assembly according to claim 1 in which the piston is movable within, and is connected by a restoring spring (31) to, a holder (24,32) which is inserted by means of a releasable fitting into that end of the casing which fits within the mouth of the cylinder. A valve assembly as claimed in claim 2 for use with a portable oxygen inhalant cylinder, comprising a valve chamber (8) provided in an upper half of a valve casing (6), an inlet port (9) of the valve chamber (8) opening at the bottom surface of the valve casing (6), an outlet port (10) opening at the side surface of the casing, a valve body (11) provided in the valve chamber (8) for opening and closing the valve, a residual pressure indicator (13), a residual pressure measuring chamber (20) provided alongside the inlet port (9) in the valve casing (6), a piston (28) arranged to slide sealing through an aperture (29) in the pressure measuring chamber (20), a balancing spring (31) connected to an inner portion (28 b ) of the piston (28) and a residual pressure indicating means (34 or 45) provided by or in association with the upper portion (28 c ) of the piston (28) so as to move lengthwise within the valve casing. A valve assembly according to claim 3, wherein a window (22) is provided for the residual pressure measuring chamber (20) so that the residual pressure indicating means (34) can be observed from outside the valve casing (6). A valve assembly according to claim 3 and further comprising a residual pressure indicating chamber (41) adjacent to the residual pressure measuring chamber (20) and a residual pressure indicating member (45) movable within the indicating chamber (41) in response to the piston (34) by means of magnetic coupling. A valve assembly according to any of claims 3 to 5, wherein a spring support sleeve (32) is connected to a foot portion (7) of the valve casing (6), and the balancing spring (31) is accommodated within the sleeve (32). A valve assembly according to claim 6, wherein the balancing spring (31) is composed of an extension spring, the lower end of the balancing spring (31) is connected to the lower end of the spring support sleeve (32), and the upper end thereof is connected to the lower end portion (28 b ) of the piston (28). A valve assembly according to claim 6, wherein the balancing spring (31) is composed of a compression spring, the upper end of the balancing spring (31) is supported by the foot portion of the valve casing (6), and the lower end thereof is connected to the lower portion (28 b ) of the piston (25). A valve assembly according to claim 3, wherein a transparent tube (23) is fitted into the residual pressure measuring chamber (20) from the under side, a holder (24) is secured air-tightly to the lower portion of the measuring chamber (20) so that the transparent tube (23) is fixedly pushed to the upper wall of the measuring chamber (20) by the upper end of the holder (24), an intermediate portion (28 a ) of the piston (28) extends through holder (24) slidably and air-tightly, the residual pressure indicating means (34) is within the transparent tube (23) and is observable through a window (22) from outside the valve casing (6), and an inner space within the transparent tube (23) communicates to the exterior by way of a passage (36). A valve assembly according to claim 9, wherein the communicating passage (36) is at the upper end surface of the holder (24). A valve assembly according to claim 9, wherein the communication passage is composed of a porous member (25) provided at at least one end of the transparent tube (23). A valve assembly according to any of claims 3 to 11, wherein the outlet port (10) is adapted to receive one inlet nozzle (15 a ) of an extractor (4).

Inventors: SAKAI, MITSUNORI
Applicants: KABUSHIKI KAISHA NERIKI
Application year: 1987
Main classification: A61M16
IPC codes: G01L7, G01L19, F17C13, A61M16