US20040099270A1 - Interlock system for gas flow device - Google Patents

Abstract

A gas flow regulator includes a one-piece housing with an internally disposed flowmeter. The flowmeter is screwed into the housing. A fitting, such as a hose barb, extends through the housing and into the body of the flowmeter to secure the pieces together. Similarly, an inner core assembly can be separately fabricated, screwed into the housing and secured by fittings. This allows a full brass core for oxygen regulators.

Description

RELATED APPLICATIONS
• This application is a Divisional of U.S. application Ser. No. 09/342,953 filed on Jun. 29, 1999, which claims the benefit of U.S. Provisional Application No. 60/091,127 filed on Jun. 29, 1998, U.S. Provisional Application No. 60/119,745 filed on Feb. 9, 1999, U.S. Provisional Application No. 60/124,704 filed on Mar. 15, 1999 and U.S. Provisional Application No. 60/127,961 filed on Apr. 6, 1999; the teachings of which are all incorporated herein by reference in their entirety.[0001]
BACKGROUND
• Gas flow regulators are used to provide a medical gas, such as oxygen, to a patient from a source supply of the gas. The gas is normally stored in a cylinder or supply vessel under high pressure. The gas flow regulator reduces the high pressure (about 500-3000 psi) to a lower pressure (about 50 p.s.i.) and provides the gas at a metered flow rate, measured in liters/minute. It is desirable to manufacture gas flow regulators as a compact, light weight and smooth to the touch package. It is also desirable to color code the devices to indicate the gas being handled (e.g., green for oxygen) or the preference of the owner of the device.[0002]
• In the prior art, compact gas flow regulators are generally constructed in either a one-piece or two-piece aluminum alloy housing. In one-piece regulators, a pressure reducing element and flow control subassembly is typically held into the housing using a c-clip or snap ring. In these devices, the c-clips do not offer adequate stability. In addition, the flow control knob is usually snapped into place and can, therefore, accidentally separate from the regulator.[0003]
• In two-piece regulators, a pressure reducing element and a piston are disposed within the yoke housing and a flow control housing, having a flow control element therein, screws together with the yoke housing. Consequently, the two-piece regulators have a characteristic division line between the yoke housing and the flow control housing. The use of two pieces also results in additional cosmetic problems. For example, it can be difficult to uniformly color the two housings due to variations in anodizing the pieces. Although two-piece regulators have a less desirable cosmetic appearance than one-piece regulators, the threaded attachment provides certain durability advantages.[0004]
SUMMARY OF THE DISCLOSURE
• In accordance with a particular embodiment of the invention, a gas flow regulator combines the durability advantages of two-piece “screw together” regulators with the cosmetic advantages of one-piece “c-clip” regulators. In particular, internal components are fabricated with a thread over their major diameter and are screwed into a yoke body which is fabricated to have a threaded minor diameter. The internal components are further secured in place by a fitting.[0005]
• This combination of parts yields a one-piece regulator with improved durability and stability. In addition, the flow control knob is connected to the flow control body in such a way that the knob cannot separate from the regulator during use.[0006]
• The modular system also permits the use of internal components that can be fabricated from a different material than the yoke body. As such, the yoke body can be made from aluminum and the internal components can be made from brass. The resulting regulator can thus realize the advantageous of each material.[0007]
• In accordance with an embodiment of the invention, a gas flow device includes an outer body with an inner cavity formed therein. The inner cavity is bounded by an inner wall of the outer body, which can have a first coupling feature. An inner element, such as a pressure reduction element or a flow meter assembly, is disposed in the inner cavity. The inner element has an external wall with a second coupling feature. The inner element is secured within the inner cavity by mating the first and second coupling features.[0008]
• The first and second coupling features can be matable threads. The coupling features can also include a fitting that extends through the outer body and engages with the inner element to further secure the inner element within the outer body.[0009]
• In accordance with another embodiment of the invention, a medical gas flow device provides gas at a selected flow rate from a pressurized supply tank. The device includes an outer body of a first material for physically connecting to the supply tank.[0010]
• An inner core assembly is disposed within the outer body. The inner core assembly has an inlet for interfacing with gas from the supply tank and an outlet for outputting the gas at the selected flow rate. The gas traverses a gas flow path formed from a second material through the inner core assembly from the inlet to the outlet. In a particular embodiment, the outer body and the inner element or core assembly are of different materials. Specifically, the outer body is made of aluminum and the inner element is substantially made of brass.[0011]
BRIEF DESCRIPTION OF THE DRAWINGS
• The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of embodiments of the gas flow device, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention.[0012]
• FIG. 1 is a cross-sectional diagram of a particular gas flow regulator.[0013]
• FIG. 2 is a cross-sectional diagram of the gas flow regulator of FIG. 1, rotated 90°.[0014]
• FIG. 3 is an exploded view, partially in cross-section, of the gas flow regulator of FIG. 2.[0015]
• FIG. 4 is a cross-sectional diagram of a gas flow regulator with a full-core insert.[0016]
• FIG. 5 is a diagram of the yoke body of FIG. 4 rotated 90°.[0017]
• FIG. 6 is a cross-sectional diagram of the pressure reduction element of FIG. 4.[0018]
• FIG. 7 is a schematic diagram of the primary gas flow paths through the regulator of FIG. 4.[0019]
DETAILED DESCRIPTION
• FIGS. 1 and 2 are cross-sectional drawings of a particular gas flow regulator. The regulator[0020]1 includes a yoke body orhousing10, aflowmeter assembly element20, a piston element30 a fitting such as, ahose barb40, agauge50 and a T-handle60. Theyoke body10 is of a unibody construction to facilitate a secure and stable attachment to a gas supply cylinder (not shown). At a proximal end, the regulator is clamped to a cylinder or tank post of the supply cylinder by thehandle60. Apressure reducing region11 of theyoke body10 reduces the supply tank pressure to about 50 psi, as known in the art.
• The[0021]piston30 andflowmeter assembly20 cooperate to supply the desired gas flow. Theflowmeter20 includes acontrol knob25 for selection of a metered gas flow rate. Aflowrate view window15 through theyoke body10 allows the user to view a selected flow rate registered to the setting (not shown) of theknob25. Note that in FIG. 2 theflowrate view window15 is shown rotated45° from its true position to show details. The metered gas from theflowmeter20 exits the regulator through thehose barb40 at a distal end. Arelief vent16 extends through theyoke body10 into the region of thepiston30 to vent high pressure gas in the event of a piston failure.
• FIG. 3 is an exploded view, partially in cross section, of the gas flow regulator of FIG. 2. The[0022]piston30 is received by apiston cavity13 formed in theyoke body10. Likewise, theflowmeter element20 is received by asecond cavity12 in theyoke body10. As illustrated, theflowmeter element20 has a nominal major diameter D₂₀which matches a nominal minor diameter d₁₂of theflowmeter cavity12. Thepiston30 also has a major diameter D₃₀which matches the minor diameter d₁₃of thepiston cavity13.
• The flow rate is determined by an[0023]orifice plate21, which is attached to theknob25 and thus theflowmeter element20 by a retainingscrew22. Details of the orifice plate can be found in co-pending U.S. Pat. No. 6,053,056, entitled “Orifice Plate for Metering the Flow of a Medium” by LeNoir E. Zaiser et al., the teachings of which are incorporated herein by reference in their entirety. As can be seen, the retainingscrew22 secures theknob25 to theflowmeter element20.
• The[0024]flowmeter element20 is, in turn, secured to theyoke body10 by respectivematable threads27,17 and theengagable barb40. Thethreads17,27 are timed such that abarb port24 in theflowmeter element20 is center aligned with anoutput aperture14 through theyoke body10 and theflowrate view window15 is aligned with flow rate numberings (not shown) on theknob25 when theflowmeter element20 is properly torqued into theyoke body10. Theyoke body10 andflowmeter element20 are locked in place by thebarb40, which is screwed through theoutput aperture14 and into thebarb port24. This interlocking arrangement of parts using thethreads27 on the major diameter D₂₀of theflowmeter body20 yields a strong, durable and stable connection.
• It should be understood that other output connectors, such as a DISS check valve, can be used in place of, or in addition to, the[0025]hose barb40. The other output connectors can also be used as fittings. It should also be understood that for clarity of description certain parts, such as O-rings and pins, are not illustrated. Although thepiston cavity13 andpiston30 are not shown as being threaded, threads may be included.
• Because the exterior housing of the regulator can be a single piece, the regulator enjoys the cosmetic benefits of prior one-piece regulators, but in a more durable and stable package. For example, the one-[0026]piece yoke body10 can be anodized or otherwise processed to a desired color. Consequently, the regulator can easily be manufactured to have a uniform color. In addition, theyoke body10 can be laser etched.
• In the embodiment shown in FIGS.[0027]1-3, thepressure reducing region11 is fabricated from the same material as theyoke body10, namely an aluminum alloy. Thepiston30 and theflowmeter20 are fabricated from brass. It is currently believed that the use of aluminum in the flow path of oxygen, especially at high pressure, may contribute to a fire potential in medical oxygen regulators due to the relatively low burning point of aluminum.
• One approach to remove aluminum from the gas flow path is to fabricate the main body of the regulator from brass or other suitable alloys. That brass main body can then be coupled to a stronger aluminum yoke. Unlike aluminum, however, brass cannot be anodized, which limits the manufacturer's ability to color code the regulators. Perhaps more importantly, it may be more difficult to manufacture a suitably secure and rigid coupling. In addition, the increased amount of brass would increase the cost of the regulator without necessarily offering improved quality.[0028]
• FIG. 4 is a cross-sectional diagram of a gas flow regulator with a full-core insert. As illustrated, the regulator is similar to the regulator of FIGS.[0029]1-3, except that theyoke body100 receives apressure reduction element170. Thepiston30 resides inside a cavity of thepressure reduction element170 defined by anextended wall175. Theflowmeter assembly20 interfaces with thepiston30 within the cavity of thepressure reduction element170. Also shown is ayoke inlet180 for interfacing with the supply tank (not shown). A highpressure gauge port150L,150R for left or right-handed gauges is also shown.
• As shown, the[0030]pressure reduction element170 includes avent hole176. Theyoke body100 includes avent window106 having a larger diameter than thevent hole176. As such, a user can see a section of thepressure reduction element170 through thevent window106 and can visually verify that the core is a suitable material such as brass. More importantly, in the event of a fire, the largerdiameter vent window106 in thealuminum yoke body100 reduces the opportunity for any flames ejected from the piston area through thevent hole176 to ignite the aluminum.
• FIG. 5 is a diagram of the yoke body of FIG. 4 rotated 90°. Exterior features include a hose[0031]barb output aperture104, a highpressure gauge aperture102, avent window106, and aflowrate view window105. Interior features include amain cavity130 having a minor diameter d₁₃₀for receiving the pressure reduction element170 (FIG. 4).Threads117 are formed at aneck region111 of themain cavity130. Theneck cavity111 has a minor diameter d₁₁₁.
• FIG. 6 is a cross-sectional diagram of the pressure reduction element of FIG. 4. The[0032]pressure reduction element170 includes thepressure reducing features110 for yielding a 50 psi internal pressure from the supply pressure. Aninlet cavity179 receives the inlet180 (FIG. 4).
• A[0033]neck portion171 has a major diameter D₁₇₁which matches the minor diameter d₁₁₁of the neck cavity111 (FIG. 5).Threads177 on theneck171 of thepressure reduction element170 mate with the threads117 (FIG. 5) of theyoke body100. The body of thepressure reduction element170 has a major diameter D₁₇₀which matches the minor diameter d₁₃₀of the main cavity130 (FIG. 5). Note that thepiston cavity13 is now located within thepressure reduction element170.
• It should be recognized that the[0034]extended wall175 can be further extended to receive theflowmeter assembly20. For example, thewall175 may extend to theoutput aperture104 or to the flowrate view window105 (FIG. 5). Such a configuration can be achieved by increasing the diameter D₁₇₀of thepressure reduction element170 and increasing the diameter d₁₃₀of the main cavity130 a suitable amount. Alternatively, thepiston30 may reside in a cavity defined by a wall of theflowmeter element20 instead of thepressure reduction element170. Such embodiments may reduce the need for certain O-rings, reducing the number of parts and simplifying assembly of the parts.
• When assembled, the[0035]high pressure gauge50 extends through thegauge aperture102 and engages agauge port150L,150R to help secure thepressure reduction element170 in place. Thethreads117,177 are timed such that, when thepressure reduction element170 is properly torgued, thegauge port150 is concentrically aligned with thegauge aperture102 and thevent hole176 is concentrically aligned with thevent aperture104, within allowed tolerances. Because thegauge50 screws into thepressure reduction element170, the high pressure gas flow directly from thepressure reduction element170 to thegauge50 without being exposed to the aluminum in theyoke body100. In a particular embodiment, a Teflon shim at theneck171 of thepressure reduction element170 is used to further secure thepressure reduction element170 without theyoke body100.
• FIG. 7 is a schematic cross-sectional diagram of the primary gas flow paths through the regulator of FIG. 4. High pressure gas from a[0036]supply tank2 enters the regulator through thecoupler180 and flows along ahigh pressure passage172 of thepressure reducing element170 to thepressure reducing feature110, which can be a smaller diameter passage dimensioned to provide a working pressure. The high pressure gas also flows into one or morehigh pressure ports150, which are threaded to receive apressure gauge50 or other high pressure devices. This constitutes a normal highpressure flow path1000. If the pressure reducing element is operating correctly, the gas pressure is reduced and flows into thepiston chamber13. The low pressure gas is maintained at the desired pressure by apiston assembly30, which is shown compressed to its over-pressurize position.
• Normally, the low pressure gas flows along a[0037]piston passage35 of thepiston assembly30 and through theorifice plate21, which determines the flow rate of the gas. After passing through theorifice plate21, the gas flows through aflowmeter passage23 and enters anoutput port24 to which abarb40 or other fitting (FIG. 3) is coupled to deliver the gas to the patient. This is thedelivery flow path1002.
• In the event of an abnormal pressure buildup, such as resulting from a failure of the[0038]pressure reducing feature110, high pressure gas can enter thepiston chamber13. To prevent this over-pressurized gas from being delivered along thedelivery path1002 to the patient, there is avent176 to the atmosphere. More particularly, as the pressure in the piston chamber increases, thepiston assembly30 compresses its spring until thepiston chamber13 is in communication with thevent176 forming avent pathway1004. Thecorresponding opening106 in thehousing100 is dimensioned to be outside the flow path.
• Regulators embodying aspects of the invention are commercially available from Inovo, Inc. of Naples Fla. and distributed by various distributers, including Tri-anim of Sylmar, Calif. under the trademark Magnus.[0039]
• While this invention has been particularly shown and described with references to embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.[0040]
• For example, although the interior elements are shown and described as coupling with the exterior yoke body using matched and timed threads, other couplings may be used, including twist-lock couplings. In addition, the configuration required to couple the regulator to a gas supply source is defined by the Compressed Gas Association (CGA). The configuration described herein is for a CGA-870 tank connection, but the invention can be employed in other configuration including CGA-540 nut and nipple connections. Furthermore, aspects of the invention can be employed in other gas flow devices, such as pressure reducers.[0041]

Claims (20)

What is claimed is:

1. A gas flow device comprising:

an outer body having an inner cavity formed therein, the inner cavity bounded by an inner wall of the outer body, the inner wall having an orifice extending through the outer body;

an inner element within the inner cavity, the inner element having an external wall with a coupling feature, the coupling feature aligned with the orifice; and

a gas fitting extending through the orifice and coupling with the coupling feature.

2. The device ofclaim 1 wherein the outer body and the inner element are of different materials.

3. The device ofclaim 2 wherein the outer body comprises aluminum.

4. The device ofclaim 2 wherein the inner element is substantially made of brass.

5. The device ofclaim 1 wherein the coupling feature includes matable threads.

6. The device ofclaim 1 wherein the inner element is at least one of a pressure reduction element or a flowmeter assembly.

7. The gas flow device ofclaim 2 wherein the outer body has a first ignition point in the presence of high pressure oxygen and the inner element has a second ignition point in the presence of high pressure oxygen, wherein the second ignition point is higher than the first ignition point.

8. A method of fabricating a gas flow device, comprising:

forming an outer body;

forming an inner cavity in the outer body, the inner cavity bounded by an inner wall of the outer body;

forming an orifice through the outer body to the inner wall;

forming an inner element having an external wall with a second coupling feature;

mounting the inner element in the inner cavity; and

extending a gas fitting through the orifice and coupling the gas fitting with the coupling feature to secure the inner element within the inner cavity.

9. The method ofclaim 8 further comprising forming the outer body and the inner element from different materials.

10. The method ofclaim 9 wherein the outer body comprises aluminum.

11. The method ofclaim 9 wherein the inner element is formed substantially from brass.

12. The method ofclaim 8 wherein the coupling feature includes matable threads.

13. The method ofclaim 8 wherein the inner element is at least one of a pressure reduction element or a flowmeter assembly.

14. The method ofclaim 8 further comprising:

forming the outer body of a material having a first ignition point in the presence of high pressure oxygen; and

forming the inner element of a material having a second ignition point that is higher than the first ignition point.

15. A gas flow device for delivering a flow of medical oxygen at a prescribed dosage from a pressurized supply vessel to a patient, comprising:

an outer body formed from a unitary piece of a first material having a first ignition point, the outer body having an integrated yoke matable to the pressurized supply vessel and an inner cavity formed in the outer body, the outer body and the inner cavity bounded by an inner wall of the outer body;

an inner core having a pressure reduction element and an oxygen flowpath through the pressure reduction element, the flowpath through the pressure reduction element formed from a second material having a second ignition point higher than the first ignition point, the inner core extending within the inner cavity; and

a fitting extending through the outer body and engaging with the inner core to secure the inner core to the outer body.

16. The gas flow device ofclaim 15 wherein the fitting is a hose connector.

17. The gas flow device ofclaim 15 wherein the fitting is a pressure gauge.

18. The gas flow device ofclaim 15 wherein the fitting is a check valve.

19. The gas flow device ofclaim 15 wherein the first material comprises aluminum and the second material comprises brass.

20. The gas flow device ofclaim 15 wherein the securing mechanism includes a coupling for attaching the inner core to the inner wall of the outer body.

Images