US2693178A - Demand type gas regulator - Google Patents

Description

1954 Y J. GILROYI ugh/1AM: TYPE GAS REGULATOR Filed Dec. 21, 1949 3 Sheets-Sheet l INVENTO R JOHN GILROY 3 awkx ATTORNEYS Nov. 2, 1954 I J. GILROY 2,693,178

DEMAND TYPE GAS REGULATOR Filed Dec. 21, 1949 3 Sheets-Sheet 3 46/9,; I ,5 l6 1 1/ 50 F|G.4 "=7;

INVENTOR JOHN GILROY 7 ATTORNEYS United States Patent This invention relates to demand type gas regulators for use in connection with breathing apparatus. More particularly it relates to an improved gas regulator for use in the respiratory administration of nebulized therapeutics or the like.

A need exists in the field of inhalational therapy,

John Gilroy, Sun Prairie, Wis., assignor to Air Reduction and particularly in the administering of nebulized antibiotics via the broncho-pulmonary route, for an interrupted demand type gas regulator, i.. e. a. type of regulator which would function automatically upon the breathing of the patient to deliver a small but su-fiicient amount of oxygen or some other gas under regulated pressure to the antibiotic nebulizer during the initial portion of each inhalation and would interrupt the gas flow prior to the end of the inhalation and well prior to the patients exhalation. The gas regulator should also preferably have means for varying the pressure against which the patient exhales. An automatic interrupted gas regulator of this type would eliminate manual controls, render more eflicient and efficacious treatment, and eflect substantial savingsin gas and antibiotics.

The principal object of the invention is to provide an automatic interrupted gas regulator which will fill this need.

Another object of the invention is to provide a novel type of suction-opened air inlet. check valve for use in such a gas regulator and whose characteristic way of operating is largely responsible for the functioning of the gas regulator in its desired way.

A gas regulator embodying the invention is illustrated in the accompanying drawings, in which:

Figure 1 is a perspective view of a complete breathing appartus of which the improved gas regulator forms a part;

Fig. 2 is a longitudinal section through the gas regulator taken approximately along the line 2--2 of Fig. 3';

Fig. 3 is a longitudinal section through the gas regulatgr taken approximately along the line 33' of Fig. 2; an

Fig. 4 is" a longitudinal, section through a gas regulator having a modified form of air inlet check valve, the plane of the'section being the sameas in Fig. 3'.

Referring first to Fig. 1 the drug to be administered is held in a nebulizer 10 which is connected to an oronasal mask 11 worn by the patient 12. A flexible gas tube 13 leadsfrom the interrupted demand regulator, denoted in general by the reference numeral 14, to the nebulizer 10 and provides gas on demand at regulated pressure to the nebulizer. The regulator 14 is connected in the usual manner to a cylinder 15 containing the oxygen or other gas to be supplied to the nebulizer. A second flexible tube 16, hereinafter calledthe breathing tube, connects the mask and the regulator.

- The nebulizer 10' and mask 11 form no part of this invention and may be any of several well-known types. Very small quantities of oxygen under pressure admitted to the nebulizer dispense the drug into the mask for inhalation by the patient.

Heretofore it has been necessary to dispense the drug continuously during inhalation or to dispense it intermittently through manual control by the patient. When the drug is continually dispensed during the inhalation period, a large part of it is again rejected by the patient. on exhalation. Since the amount retained and the amount rejected by the patient is then'indeterminate, it is impossible for the administeringv physician to accurately control the treatment. In addition, this repre 2,693,178 Patented Nov. 2, 1954 sents a wasteof thedrug. Manual control. by the patient is: also unsatisfactory because it relies somewhat on his judgment and dependability, which may not be adequate. In fact, in some cases the patients physical condition does not permit his performance of this duty.

The present interrupted gas regulator overcomes all these diificulties by automatically dispensing the drug for a short period only at the beginning of each inhalation in the breathing cycle. In this way virtually all the. drug is retained. by the patient.

The interrupted gas regulator itself comprises a regul-ator body 17 to which high. pressure oxygen is admitted from. the oxygen cylinder 15 through an inlet connection 18 and inlet port 19 (see also Figs. 2 and 3'). A tap 20 on the inlet port 19 (Fig. 2) connects with a high pressure gauge G which indicates cylinder pressure. flexible diaphragm 21 (Fig. 3) loaded by means of a spring 22, encloses the regulated pressure chamber 23 and controls the operation of the regulating valve 24 in the manner well known in the gas regulator art. This structure automatically maintains the oxygen in chamber 23 at some predetermined pressure. For example, the oxygen cylinder pressure may be of the order of 2000 p. s. i. while the oxygen in the regulated pressure chamber may be at a pressure around 30 p. s. i.

A demand valve 25, when opened against the action of a closing spring 258, admits oxygen from the regulated pressure chamber 23 to the regulator discharge port 26 (Figs..2 and 3). The discharge port 26 leads to an outlet connection 26 (Figs. 1 and 2) to which the above-mentioned gas tube 13 is connected. The mechanism for automatically actuating the demand valve 25' in accordance with the patients' breathing. cycle is as follows The demand valve 25 is actuated by levers 27 and28 in re sponse to movement of a. diaphragm 29 that forms one wall of a suction or control chamber 30. There is negligible leakage around the demand valve stem. The d1aphragm 29 is subjected at its outer side to atmospheric pressure. The suction chamber 30 under the diaphragm is in communication with breathing tube 16 through the breathing valve housing 31. (Fig. 3). This breathing valve housing. contains two valves, an air inlet check valve 32, hereinafter called the inhalation check valve, and an exhalation outlet check valve 33. The exhalation valve is a simple spring loaded relief valve. The valve disc 34 of the exhalation valve seats on a seating surface of the housing 31. The disc 34 slides on a fixed guide rod 35 to open against the pressure of spring 36 only, or spring 36 andspring 37, depending on the setting of an exhalation pressure control knob 38. As this'knob is screwed in, spring 37 moves in with it and the inner end of the'spring bears against the valve disc 34' with as much pressure as desired. When the exhalation pressure control knob 38 is in its retracted position, as illustrated, the only pressure on the. exhalation valve disc 34 is the. very light bias produced by spring 36. The breathing valve housing 31 and the various elements supported by and contained within it, as pointed out above, including breathing tube 16, may be collectively termed inhalation means and are so termed in the appended claims.

At the other end of the housing 31 is the inhalation check valve 32. This valve is more than a check valve in the ordinary use of the term, since it has special operating characteristics. A greater pressure differential is required to open the valve initially than to keep it open thereafter. In the preferred form of the invention, the inhalation valve 32 is a magnetic check valve. This magnetic check valve comprises an annular magnet 40, preferably a permanent magnet, the inner edge portion of which constitutes a valve seat, and a paramagnetic or ferromagnetic valve disc 41 which is free to slide on a fixed guide rod 35. A shoulder 42 in the housing 31 acts as a stop for the valve disc 41 in its fully open position. The check valve controls the passage of atmospheric air from an air inlet 41' to the breathing tube 16.

The operation of the apparatus described above is as follows: Fig. 3 shows the parts of the gas regulator in the position they would assume just prior to inhalation by the patient. As inhalation begins, a partial vacuum or suction is produced in the breathing tube 16. and thus in the regulator chamber 30 under diaphragm 29. This permits the atmospheric pressure on the outer side of the diaphragm to force the diaphragm in. As the diaphragm is depressed, the system of levers 27 and 28 pushes in the stem of the demand valve 25, opening the demand valve when the suction under the diaphragm is approximately 0.25 of water. The oxygen regulated from cylinder pressure to approximately 30 p. s. i. flows through the demand valve 25, the regulator discharge port 26, and the flexible tube 13 to the nebulizer 10. Nebulization of the drug solution begins.

As inhalation continues, and still in the early part of the inhalation phase, the partial vacuum in the breathing tube 16 becomes sufiicient (about 0.5 water) to pull the inhalation check valve disc 41 away from its magnetic seat. Air then passes the check valve from the air inlet 41' and reduces the partial vacuum in the regulator chamber 30 to about 0.05" water. This is the result of the fact that it requires a much greater pressure differential to release the valve disc 41 from its magnetic seat than is required to keep it up ofi the seat once it is unseated. Against this small suction, the demand valve spring 255 can return the diaphragm 29 to its starting position and close the demand valve 25, thus interrupting the flow of oxygen. Nebulization of the drug solution does not cease, however, until a little later in the inhalation phase when the oxygen supply in the line 13 becomes depleted. This, however, is still prior to the end of the inhalation phase. Because of the manner in which the interrupted demand regulator works, substantially all of the drug nebulized is drawn into the patients respiratory passages instead of being wasted in the exhalation phase of the breathing cycle. Also a maximum degree of oxygen economy can be achieved, since oxygen flow from the regulator occurs only during a small portion of the breathing c cle.

When the inhalation phase of the breathing cycle is completed and exhalation begins, the magnetic check valve 32 closes. The reversal of flow in the breathing tube 16 as exhalation begins may be utilized to assist the magnet 40 in closing the inhalation valve if the connection 16' by which the breathing tube is connected to the breathing valve housing 31 is positioned as illustrated. The exhalation outlet valve 33 then opens against the force of spring 36 which is very light, producing substantially no exhalation back pressure. In some instances, however, greater exhalation back pressure is required, as in the treatment of sinusitis where the pressure changes during the breathing cycle loosen mucous plugs, and pressure during the exhalation phase tends to drive the treating drug into the sinus passages. To obtain this required greater exhalation back pressure, the exhalation pressure control knob 38 is advanced toward the exhalation valve disc 34. This moves spring 37 into operative contact with the exhalation valve disc which then resists the opening of the valve. Thus any desired exhalation back pressure can be produced depending upon the position of the exhalation pressure control knob.

It will now be seen that it is the operating characteristics of the magnetic inhalation check valve 32 that make my improved interrupted demand regulator possible. Other valve structures may be employed as inhalation check valves, providing the structure thereof is such that the means for providing force biasing the valve element to closed position is such that as the valve opens such force decreases. Such other valve structures are, of course, contemplated as coming within the scope of this invention.

One such alternative or modified valve structure is illustrated in Fig. 4, which is a sectional view of a gas regulator like that shown in Fig. 3 but having the modified valve structure in place of the magnetic check valve above described. With this mechanical type inhalation check valve, the breathing valve housing 43 may assume a slightly different shape from that employed with the magnetic check valve. The modified check valve comprises a valve disc 44 which seats on a valve lip 45 formed on the casing 43. The valve'disc is supported at the end of an arm 46 which is pivoted at 47. A coil spring 48 has one end attached to the valve housing at 49 and the other end attached to the valve arm 46 as shown. The torque produced by the spring tending to keep the valve closed when it is seated is equal to the product of the spring force and the effective lever arm L. As inhalation commences, a partial vacuum is created within the breathing tube 16 and the communicating passages, effective to open the oxygen demand valve in the regulator as previously described. When the pressure differential between the interior of the breathing valve housing 43 (breathing tube pressure) and the atmosphere reaches approximately 0.5" of water, the closing torque produced by spring 48 is overcome and the valve disc 44 lifts off the lip 45. The farther the valve disc opens the less the torque produced by the spring becomes, since the effective lever arm L through which the spring force is working diminishes as the valve opens. Depending on the location of a valve arm stop pin 50, the closing torque at the full open position may be very small, zero, or even negative. In any event the air which now enters the apparatus past the inhalation check valve reduces the partial vacuum in the chamber 30 (Fig. 3) of the gas regulator permitting the demand valve to close. As exhalation commences, the inhalation check valve closes and the exhalation valve 33 opens as previously explained. It should be noted that the inhalation check valve disc 44 when in open position lies opposite the place at which the breathing tube 16 and its housing connection 16 communicate with the interior of the valve housing. This adds to the speed and efiiciency of operation because the first reversal of flow in the breathing tube will give the valve a closing push. While this is an advantageous feature it is not an essential one unless the spring 48 passes dead center when the valve is fully open and produces negative closing torque.

The operating characteristics of either form of the inhalation check valve above described differ substantially from the operating characteristics of a conventional check valve. As the pressure differential builds up across either of the inhalation check valves herein described, there is substantially no flow past the valve (except, possibly, for slight leakage) until the point is reached where the closing force (magnetic attraction in the case of the inhalation check valve shown in Fig. 3, and spring force in the case of the inhalation check valve shown in Fig. 4) is overcome. In both forms of the inhalation check valve the more the valve opens the less the closing force becomes in the Fig. 3 modification and the less the torque becomes in the Fig. 4 modification. Additionally the less the respective closing force or torque becomes the more the valve opens. This cumulative effect thus permits the valve to open smoothly and rapidly to the full open position, and the pressure drop across the open valve is reduced to substantially that of an orifice of the size of the valve. The particular inhalation check valves herein described open at a pressure differential of about 0.5 of water, and the pressure diiferential drops to 0.01" of water when the valve opens. The latter relatively low pressure differential is suflicient to keep the valve open, and the valve may be caused to continue to open to its fully open position, with a corresponding increase in the flow past the valve, by only a small gradual increase in the difierential pressure. While the closing force on a conventional check valve could be regulated so that the valve opens at the same pressure dilferential as in the case of the inhalation check valves herein described, namely, 0.5" of water, this relatively high pressure differential would have to be maintained to keep the valve open and thereafter, for any given flow past the valve, the pressure differential required to open the valve the necessary amount would be considerably greater than in the case of the inhalation check valves herein described.

While, as'will be clear from the above, it is intended that the pressure regulator of this invention be employed primarily in direct connection with a breathing mask for use n the respiratory administration of nebulized therapeutics or the like directly to patients, it will be clear that the regulator might further be employed to provide such nebulized theapeutics indirectly to patients, and furthermore might be utilized to provide other nebulized substances to other than patients. To fully describe the im proved gas regulator itself, it is necessary to make reference to whatever it is that is being supplied with the nebulized material and produces a reduced pressure to cause proper operation of the gas regulator to effect such supply, whether it be a human patient or something else. Therefore, in the appended claims reference is made generically to pressure-reducing means.

It should be additionally understood that the term closing force as used in the following claims refers both to a force such as the magnetic force responsible for closing the valve in the modification of Fig. 3 and the i orqlie imposed by the spring in the modification of I claim:

1. In a gas regulator, a body portion having an inlet adapted to be connected to a source of gas under relatively high pressure and also having an outlet, means for reducing the pressure of the gas on its Way from the inlet to the outlet, a demand valve for controlling the passage of the low pressure gas to the outlet, means includlng a control chamber for controlling saiddemand valve, the demand valve being constructed to open when the pressure in said control chamber decreases to a predetermined value and to close when the pressure in the control chamber increases to a predetermined value, a connection on the body portion of the regulator communicating with said control chamber and adapted to be connected by a tube to pressure-reducing means by which the pressure in such chamber may be varied, said control chamber being isolated from the gas passing through the body portion of the regulator, an air inlet through which atmospheric air may be admitted to the regulator and to said last-named connection and a check valve controlling said air inlet, said check valve comprising a movable valve element and means producing a closing force on the valve element which lessens as the valve opens, the check valve being constructed to open when the pressure in the control chamber is reduced by said pressure-reducing means a predetermined amount below the pressure at which the demand valve opens to thereby cause an increase of pressure in the control chamber whereby, during the first part of the period when there is a reduced pressure condition in said control chamber caused by said pressure-reducing means and before the check valve opens, gas is delivered by the regulator but after the check valve opens and during the remaining part of such period the demand valve closes and the gas supply from the regulator is shut oif by reason of the increased pressure in the control chamber.

2. A gas regulator in accordance with claim 1 in which the means including a control chamber for controlling said demand valve comprises a diaphragm for controlling said demand valve and forming one wall of said control chamber.

3. A gas regulator in accordance with claim 1 in which the seat of said air inlet check valve is made of magnetized material and the valve element is made of magnetic material whereby the closing force produced on the valve element is the magnetic attraction between the seat and the valve element.

4. A gas regulator in accordance with claim 1 in which the seat of said air inlet check valve is the edge portion of an annular permanent magnet and the valve element comprises a disc of magnetic material cooperating with the seat whereby the closing force produced on the valve element is the magnetic attraction between the seat and the valve element.

5. A gas regulator in accordance with claim 1 in which said air inlet check valve includes a pivoted arm on which the valve element is mounted, a coil spring one end of which is connected to said arm and the other end of which is fixed, the pivot of the arm lying intermediate the point at which the spring is connected to the arm and the point at which the spring is fixed, the spring normally biasing the valve element to closed position, and the effective lever arm through which the spring acts to close the valve becoming less as the valve element moves away from the seat.

6. In a gas regulator a body portion having an inlet adapted to be connected to a source of gas under relatively high pressure and also having an outlet adapted to be connected by a gas tube to a breathing mask, means for reducing the pressure of the gas on its way from the inlet to the outlet, a demand valve for controlling the passage of the low pressure gas to the outlet, means including a suction chamber for controlling said demand valve, the demand valve being constructed to open when the suction in said suction chamber increases to a predetermined value and to close when the suction in the suction chamber decreases to a predetermined value, a connection on the body portion of the regulator being adapted to be connected by a breathing tube to the breathing mask and being constructed to place said breathing tube in communication with said suction chamber, said suction chamber being isolated from the gas passing through the body portion of the regulator, and a suction-opened air inlet check valve adapted when the gas regulator is in use to open and admit air to the suction chamber and to the breathing tube and thereby lessening the suction in the suction chamber, said check valve comprising a movable valve element and means producing a closing force on the valve element which lessens as the valve opens, the check valve being constructed to open at a predetermined pressure differential on opposite sides of its valve element during the inhalation phase of a breathing cycle, whereby during the first part of the inhalation phase before the check valve opens gas is delivered to the body portion of the regulator to the breathing mask but after the check valve opens and during the remaining part of the inhalation phase the gas supply through the body portion of the regulator to the breathing mask is shut off by reason of the smaller suction in said suction chamber.

7. A gas regulator in accordance with claim 6 having an exhalation check valve which is constructed to be opened by exhalation through the breathing tube, spring means exerting a closing force on the valve element of said exhalation check valve, and means for varying the degree of the closing force exerted by said spring means.

8. A gas regulator in accordance with claim 6 in which the means including a suction chamber comprises a diaphragm for controlling said demand valve and forming one wall of said suction chamber.

9. In inhalation apparatus for administering therapeutic agents to patients in nebulized form having a gas mask adapted to receive the nebulized agent for inhalation by the patient, the combination therewith of a demand type gas regulator having a body portion which in turn has an inlet adapted to be connected to a source of relatively high pressure gas and an outlet, means for connecting said outlet to said mask including a nebulizer for dispensing the therapeutic agent into said mask with the gas when said gas is delivered from the regulator, a demand valve in said regulator between said inlet and said oulet which when closed prevents passage of gas from said inlet to said outlet but which when opened permits such passage of gas, pressure responsive means for operating said demandvalve, and means operatively associated with said pressure responsive means and effectively during the latter phase only of inhalation to admit air into said mask, said pressure responsive means being constructed to open said demand valve for delivering gas to said mask during the initial phase of inhalation and to close said demand valve when air is admitted to said mask during this latter phase of inhalation prior to the completion thereof.

10. Apparatus according to claim 9 in which the regulator includes means for reducing the pressure of said gast1 in passing from said regulator inlet to said regulator ou et.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,319,787 Moron Oct. 28, 1919 2 41.216 Wiggins May 11, 1948 2,535,844 Emerson Dec. 26, 1950 2,552,595 Seeler May 15, 1951 2,597,039 Seeler May 20, 1952 FOREIGN PATENTS Number Country Date 212,570 Germany Aug. 5, 1909

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