WO2015070878A1

WO2015070878A1 - Pressure- and flow regulation valve

Info

Publication number: WO2015070878A1
Application number: PCT/DK2014/050388
Authority: WO
Inventors: Thyge Rahbæk DUEHOLM
Original assignee: Müller Gas Equipment A/S
Priority date: 2013-11-14
Filing date: 2014-11-14
Publication date: 2015-05-21

Abstract

The present invention discloses a pressure and flow control valve (1) for use in connection with stepwise regulation of a flow, wherein the control valve (1) in addition to a connection (10) for a pressure source includes at least a pressure outlet (8) with a pressure P2 and a flow outlet (5) with a pressure P3, respectively, wherein between the connection (10) for a pressure source and the pressure outlet (8) there is arranged at least one first pressure control step (11) for regulating a gas pressure PI from a first level to a second, lower level, the control valve (1) further including at least one second pressure control step (12) for regulating a gas pressure from a first level to a third, lower level, the second pressure control step (12) arranged between the pressure source/connection (10) and the flow outlet (5), with the object, among others, of enabling the use of gas from a pressure outlet without any appreciable pressure reduction occurring on a flow outlet.

Description

PRESSURE AND FLOW REGULATION VALVE

Field of the Invention

The present invention concerns a pressure and flow control valve for use in connection with stepwise regulation of a flow, wherein the control valve in addition to a connection for a pressure source also includes at least a pressure outlet and a flow outlet, wherein between the connection for a pressure source and the pressure outlet there is arranged at least one first pressure control step for regulating a gas pressure from a first level to a second, lower level, the control valve further including at least one second pressure control step for regulating a gas pressure from one level to a third, lower level, the second pressure control step arranged between the pressure source/connection and the flow outlet. Description of Prior Art

It is common knowledge to use control valves in connection with use of gas, including during the use of medical gases, such as e.g. oxygen, which are supplied to a user via a face piece or via tubes in the nose. Such gases are typically stored at high pressure in a pressure container and supplied to the point of consumption or the user at a reduced pressure and in a predetermined amount which is typically measured in litres per minute (LPM).

Such a control valve may e.g. ensure supply of gas at a pressure which does not exceed a safety limit or similar, and/or is adjusted to a given consumer situation at a point of consumption or for a consumer apparatus, and which at the same time is as constant as possible, irrespectively of fluctuations or variations in the supply pressure in dependence of the degree of filling of the pressure container.

The prior art types of pressure and flow reduction valves are typically made with a valve function ensuring that the pressure from the pressure container is reduced to a suitably low level, typically to a pressure between 3 and 4.5 bar, and with a flow control capability where a flow between 0 and 25 LPM can be set. This regulated gas pressure is also called the discharge pressure which is conducted from the flow outlet of the control valve to a consumer. The discharge pressure from a pressure and flow control vale is typically fixed, and on some pressure and flow control valves there is furthermore arranged a so-called pressure outlet which is not flow controlled, but only pressure controlled to e.g. 3, 4 or 4.5 bar, called P2.

The part of the gas to be used for direct supply to a patient in order to assist with the oxygen uptake or for another form of medical therapy with gas is therefore pressure and flow controlled whereas the part of the gas supplied to the pressure outlet is only pressure controlled. The said pressure outlet can e.g. be used for connecting other medical equipment, such as equipment for sucking mucus and blood from the airways of a patient, for a lung ventilator or for other purposes.

Such combined pressure and flow control valves are widely used, since this is a simple solution and since one may suffice with a single valve unit. However, there are also some drawbacks associated with these types of combined valves which will be emphasised in the following.

In the prior art types of pressure and flow control valves, so-called loose flow discs are frequently used. These flow discs are made with a plurality of rather small openings, typically with a diameter down to 0.06 mm corresponding to 60 μπι, which by proper positioning allow a given amount of gas to be dosed through these openings. The smaller openings, also called apertures, present in the flow disc, the smaller flow of gas is supplied to the patient. In order to protect the regulating parts it is prescribed in some cases that such a valve is to be provided with a so-called 100μ filter corresponding to 0.1 mm. However, it is not quite fine enough to protect the smallest flow controlling apertures, why these in principle can be clogged without anybody noticing. Clogged flow controlling apertures can appear to be fatal as an intended amount of gas, e.g. oxygen, is possibly not supplied to a patient.

In order to ensure sufficient rigidity and wearability in a flow disc, these are typically made of a relatively thin steel or metal sheet, typically with a thickness down to 0.08 mm, though they may have a thickness of up to 2-3 tenths of a millimetre, where the apertures made for allowing correct and balanced flow are, as mentioned, rather small. The said apertures are typically with a diameter between 0.06 and 0.5 mm, and the apertures are typically made in groups of two such that a faulty disposition of the handwheel and thereby of the flow disc between two steps result in that gas is still supplied to a consumer, though only in half amount.

By combined pressure and flow control valves of the prior art type it is also a drawback that in case where gas from the pressure outlet P2 is used, the pressure P3 is for the flow outlet is reduced as well, thereby also reducing the flow. As mentioned, this is not acceptable as a patient is often not capable of performing regulation of the flow by himself, and a doctor or nurse can also easily overlook such a reduced flow. Particularly when most of such pressure and flow control valves are not equipped with an actual flow indicator, but only with indication of the step at which it is set. Such an indicator is of course only indicating true when the nominal pressure P3 is maintained as well.

It is the object of the invention to indicate a pressure and flow control valve where the above mentioned inexpediencies are countered, and where gas from a pressure outlet can be used without any appreciable pressure reduction occurring on a flow outlet.

Description of the Invention

As mentioned in the introduction, the present invention concerns a pressure and flow control valve for use in connection with stepwise regulation of a flow, wherein the control valve in addition to a connection for a pressure source also includes at least a pressure outlet with a pressure P2 and a flow outlet with a pressure P3, where between the connection for a pressure source and the pressure outlet there is arranged at least one first pressure control step for regulating a gas pressure PI from a first level to a second, lower level, the control valve further including at least one second pressure control step for regulating a gas pressure from one level to a third, lower level, the second pressure control step arranged between the pressure source/connection and the flow outlet. Hereby is achieved the great advantage that any dependence between flow outlet and pressure outlet no longer exist. This means that even if there is a high consumption on the pressure outlet P2, this has no influence on the pressure P3 and thereby on the flow available at the flow outlet. When e.g. a pressure outlet is used as drive means for a suction simultaneously with a patient being supplied with a given flow of gas, by the prior art solutions there will be effected a regular and more or less perceptible loss of pressure in the flow regulation. This means that either a patient or a care person is to perform a manual regulation of the flow to a higher level on the scale in order to maintain the desired flow of gas. At the same time, this also means that after ending use of the equipment coupled to the pressure outlet, a reverse regulation is to be effected in order not to supply too high pressure to a patient. This adjustments up and down are not desirable in that as mentioned above a regular and immediate sense is to be applied in order to perform these adjustments. By using a control valve according to the invention, a constant and independent flow is thus ensured irrespective of the occur- rence of a large, a small, or no consumption at all on the pressure outlet of the control valve.

This means that the two pressure ranges in the valve P2 and P3 operate independently of each other even if they receive gas from the same container. By the invention is also achieved a higher safety level compared with corresponding solutions with one step regulation. A one-step system has only a single regulating step that separates a high pressure section from a low pressure section. If this single step fails, the full pressure of the pressure container of maybe 200 bar or 300 bar will appear directly to the patient or user. A two-step system as the present one will have a higher safety level as two control steps have to fail before high pressure can be delivered to the patient or user. Both steps failing at the same time is obviously substantially less probable compared with failure of one step. A higher safety level for the product is thereby also achieved by the invention. A possible high pressure to the patient or the user may cause death and very serious oxygen ignition, which is obviously unwanted.

Standards for how high pressure that is to be available at the actual pressure outlets are typically issued, and depending on which countries or regions, typically a fixed pressure P2 of 3, 4 or 4.5 bar is required at these pressure outlets at which the coupled equipment is designed to operate optimally. This equipment can-as mentioned, e.g. be suction equipment or other instruments or equipment in hospitals, casualty wards, ambulances and the like, where this equipment is used for treating a patient that e.g. is supplied oxygen via a face piece or via a tube in the nose.

In some cases, and particularly by the rescue equipment comprising the prior art types of pressure and flow control valves, it is common to replace the pressure bottle, which normally has a bottle pressure of e.g. 200 bar, already at a residual pressure of 50 bar. This is effected in order to avoid that the built-in alarm system are activated by using the flow outlet P3 as well as the pressure outlet P2 when the pressure in the control step drops from e.g. 4.5 bar to 3.6 bar. Such an alarm is acoustic and is absolutely unwanted in a pressed situation as the personnel is required to attempt relieving the problem causing the alarm. By using two pressure control steps, the flow out of the flow outlet at the pressure P3 will occur at an even lower pressure than the alarm pressure, and it is only at a large and probably momentary consumption on the pressure outlet that such an alarm will be activated. A markedly greater certainty that the personnel performing urgent actions can work safely and at the same time maintain the functionality of the equipment and the safety of the patient can hereby be achieved.

The need for a constant flow is i.a. present by prematurely born infants where there is a need for a constant flow of 0.05 1/min at the flow outlet, which one control step can provide for.

Also, there is a need for a flow of 130 1/min at the pressure outlet for use as service outlet at a bottle pressure of 10 bar.

The pressure regulated in the second pressure control step for regulating a gas pressure from one level, namely P2, to a third and lower level, namely P3, will typically be regulated to a pressure of 1 bar, but higher as well as lower pressure may be applied as well. Experiments and calculations have shown, however, that the pressure difference is rather to be more than 1 bar, and preferably 2 bar or even more. The new feature of a pressure and control valve according to the invention is that the control valve can include flow control means including a flow disc and a spindle, the flow disc including a number of flow apertures with an internal wall and the flow disc being connected with the spindle, wherein the spindle is arranged for rotation about an axis, wherein the flow apertures by rotation of the spindle about the axis are moved relatively and brought into a position in relation to at least one discharge Opening for yielding a stepwisely determined flow through at least one flow outlet.

By the known solutions of such pressure and flow control valves, as mentioned the same pressure exists on pressure outlet and on flow outlet. The flow openings or apertures are dimension such that the actual pressure and the actual cross-sectional area is adapted to the desired flow. AS the pressure is relatively high by the prior art solutions, the flow apertures are relatively small. By a control valve according to the invention where the pressure in the flow outlet is lower, the flow apertures can therefore be made correspondingly larger. Hereby, several advantages are achieved. Among others, the flow apertures can be made markedly more exact when they are larger as a small tolerance no longer has such a great effect as when the flow apertures in the prior art solutions are very small, down to e.g. 0.06 mm in diameter. In addition, the slightly larger flow apertures are both cheaper and easier to make than to produce the often very small apertures according to prior art.

At the same time there is the great advantage of larger flow apertures that they are not so easily clogged if any contaminants are present in the gas. In control valves of this type, normally a 100 μ or finer filter is used according to a standard for protecting the control part. A finer filter, e.g. a 60μ filter, is rather not used as this is experienced as a resistance that will reduce the flow capacity in the control valve. This happens as the built-in dimensions available for the filter are rather modest, and the finer the applied filter, the lesser area is free for the gas to flow over. Therefore, there are good reasons for keeping a 100μ filter due to the lower resistance. Such a 100 μ filter allows in prin- ciple particles less than 0.1 mm to pass. As the least flow apertures in a flow disc according to the prior art are down to 0.06 mm, clogging by particles that have passed the filter may actually happen. By a solution according to the invention, filter and flow apertures will fit markedly better as it is, as intended, the filter which has the smallest openings and therefore can retain possible impurities.

In a variant of a pressure and flow control valve according to the invention, the control valve may include at least two pressure control steps arranged in parallel. These parallel pressure control valves thus do not have any immediate mutual influence and are therefore operating entirely independently. This means that a control valve in front of the pressure outlet in principle can be supplied with a bottle pressure PI of e.g. 200 bar which is regulated down to e.g. 4.5 bar. This also means that the same high bottle pressure of e.g. 200 bar is regulated down to a pressure of about 4.5 bar, however preferably to a pressure which is not higher than 1 bar, which is effected in pressure control step arranged before the flow outlet. The said pressure examples are only to be regarded as examples, and a control valve according to the invention may readily be constructed for other pressures than those mentioned.

In a second variant of a pressure and flow control valve according to the invention, the control valve may include at least two pressure control steps arranged in series. This means that one or more control steps lower the high feed pressure PI from a bottle or other supply source to a suitable pressure P2 for the pressure outlet, whereas one or more subsequent control steps lower the pressure additionally to the desired pressure P3 in the flow control part. As the pressure P3 in the flow control part will typically be somewhat lower than in the pressure outlet P2, there is not the same sensitivity to consumption on the pressure outlet as e.g. 4.5 bar is available at the pressure outlet, whereas only e.g. 1 bar is to be used in the flow outlet in order that the flow fits the scale on the handwheel by which the flow is regulated - i.e. under the condition that the pressure is constant.

Irrespective of application of parallel or serial pressure control steps, the same advantage is achieved, as the pressure can be kept very close to constant at the flow out- let, irrespective whether there is consumption on the pressure outlet or not, and at the same time the scale fits the flow regulation irrespectively of the size of the consumption on the pressure outlet. By the invention is thus indicated a pressure and flow control valve where the flow through the flow outlet is as near constant as possible independent of whether there is a large consumption, a small consumption or not consumption at all on a pressure outlet on the control valve. At the same time, a control valve is indicated, where there is less risk of inadvertent clogging of flow apertures as these now can be designed with a larger cross-sectional area.

Short Description of the Drawing

The invention is described in more detail with reference to the drawing, where:

Fig. 1 shows a pressure and flow control valve with stepwise setting of flow and fixed pressure outlet with the pressure P2.

Fig. 2 shows the same pressure and flow control valve as in Fig. 1 , but here partly in section.

Fig. 3 shows a detail of two pressure control steps in a pressure and flow control valve.

List of designations:

1 pressure and flow control valve

2 valve housing

3 handwheel

4 flow scale

5 flow outlet with pressure P3

6 filling nozzle

7 opening/closing knob

8 pressure outlet with pressure P2

9 manometer

10 connection for pressure container with pressure P 1

11 first pressure control step

12 second pressure control step

13 Flow Disc

14 spindle

Detailed Description of Embodiments of the Invention In Fig. 1 appears a pressure and flow control valve 1 with a valve housing 2 and a handwheel 3. The actual flow for which the pressure and flow control valve 1 is set is here represented by a flow scale 4 in a cutout in the handwheel 3, and in this case the flow is set to 0 1/min. The handwheel 3 is used for stepwise setting the flow of gas conducted out of the flow outlet 5 with a pressure named P3. By turning the hand- wheel 3, the flow through the said flow outlet 5 can be increased and reduced, respectively, and also be shut off. On the pressure and flow control valve 1 is furthermore seen a filling nozzle 6 for supplying gas to a not shown pressure container/bottle on which the control valve 1 is mounted. There is also seen an opening/closing knob 7 with which the flow to the pressure outlet 8 with a pressure termed P2 can be opened and closed. Between the opening/closing knob 7 and the pressure outlet 8 is seen a manometer 9 displaying the pressure PI in the not shown pressure container which can be mounted by the connection 10. In Fig. 2 appears the same pressure and flow control valve 1 as shown in Fig. 1, but shown here partly sectioned in the part of the valve housing 2 that includes both the first pressure control step 11 and the second pressure control step 12. By a circle A is indicated an area shown in enlarged version in Fig. 3. Both Figs. 2 and 3 show an example of how a first control step 11 is arranged in the valve housing 2 and in direct connection with a second control step 12. In the shown example, the two control steps 11, 12 are arranged in series. The first control step 11 is adapted for regulating the bottle pressure (PI) from e.g. 200 bar to 4.5 bar (P2) which is thus accessible from the pressure outlet 8. The second pressure control step 12 is here adapted to regulate the already regulated pressure (P2) of 4.5 bar to a still lower pressure (P3), e.g. 1 bar (overpressure) which then is available in the flow outlet 6 via a flow disc 13 that is set via a spindle 14 connected with the handwheel 3. The indicated pressure figures are only examples, and a pressure and flow control valve 1 can readily be designed for working with other, greater as well as smaller, pressures in the flow outlet 5 as well as in the pressure outlet 8.

Finally, in Figs, 2 and 3 the designations PI, P2 and P3 are shown at the points where in the pressure and flow control valve 1 the respective pressures exist.

Claims

1. A pressure and flow control valve (1) for use in connection with stepwise regulation of a flow, wherein the control valve (1) in addition to a connection (10) for a pressure source includes at least a pressure outlet (8) with a pressure P2 and a flow outlet (5) with a pressure P3, respectively, where between the connection (10) for a pressure source and the pressure outlet (8) there is arranged at least one first pressure control step (1) for regulating a gas pressure PI from a first level to a second, lower level, the control valve (1) further including at least one second pressure control step (12) for regulating a gas pressure from a first level to a third, lower level, the second pressure control step (12) arranged between the pressure source/connection (10) and the flow outlet (5), characterised in that the control valve (1) includes flow control means including a flow disc (13) and a spindle (14), the flow disc (13) including a number of flow apertures with an internal wall and the flow disc (13) being connected with the spindle (14), wherein the spindle (14) is arranged for rotation about an axis, wherein the flow apertures by rotation of the spindle (14) about the axis are moved relatively and brought into a position in relation to at least one discharge opening for yielding a stepwisely determined flow through at least one flow outlet (5).

2. A pressure and flow control valve (1) according to claim 1, characterised in that the control valve (1) includes at least two pressure control steps (11, 12) arranged in parallel.

3. A pressure and flow control valve (1) according to claim 1, characterised in that the control valve (1) includes at least two pressure control steps (11, 12) arranged in series.