Demand regulator

Abstract

A demand regulator (100) for a breathing device (10) is disclosed, comprising: a diaphragm device (110) operatively connected with a valve device (108); a diaphragm biasing spring (130) configured to apply a biasing force to the diaphragm device (110); and a bias adjustment device (132) configured to adjust compression or deformation of the diaphragm bias spring (130), thereby adjusting a bias force applied to the diaphragm device (110). A breathing mask (18) comprising the demand regulator (100) and a breathing apparatus (10) comprising the demand regulator (100) are also disclosed.

Description

Technical Field

[0001] The present disclosure relates to a demand regulator (flow regulator) for an emergency breathing apparatus. Background Art

[0002] Emergency breathing devices typically include a demand regulator, which may also be referred to as a lung demand valve. The demand regulator is configured to deliver breathing gas to the user as needed as the user inhales. In order to provide breathing air without the user having to inhale with great effort, the demand regulator may need to be calibrated to achieve a desired flow rate. Such calibration of the demand regulator during production and use may be difficult to achieve in known demand regulators.

[0003] It will therefore be appreciated that there is a need for improvements in demand regulators with regard to calibration. Summary of the invention

[0004] According to a first aspect, a demand regulator for a respiratory device is provided, the demand regulator comprising: a housing defining an internal chamber; a valve device for controlling the flow of respiratory gas into the internal chamber; a diaphragm device, a first side of the diaphragm device being configured to be exposed to the surrounding environment, and a second side of the diaphragm device being configured to be exposed to the internal chamber, the diaphragm device being operatively connected to the valve device; a diaphragm bias spring being configured to apply a biasing force to the diaphragm device; and a bias adjusting device being configured to adjust the compression or deformation of the diaphragm bias spring, thereby adjusting the biasing force applied to the diaphragm device.

[0005] The breathing apparatus may be a self-contained breathing apparatus (SCBA), but it will be appreciated that the demand regulator may also be applicable to other types of breathing apparatus, such as self-contained underwater breathing apparatus (SCUBA) and emergency escape breathing apparatus.

[0006] The diaphragm means may be operatively connected to the valve means such that movement of the diaphragm means controls the flow of breathing gas.

[0007] The diaphragm means may comprise an elastically deformable material. The diaphragm means may comprise a substantially rigid material. The substantially rigid material may be configured to provide a contact point between the valve means and the diaphragm means. The diaphragm means may consist of a single component or may comprise multiple layers or multiple components.

[0008] Reducing the biasing force may increase the pressure differential across the diaphragm assembly required to move the diaphragm assembly. Increasing the biasing force may reduce the pressure differential across the diaphragm assembly required to move the diaphragm assembly.

[0009] The valve device may comprise a valve actuator for actuating the valve device.The valve actuator may be in contact with or connected to the diaphragm device such that movement of the diaphragm actuates the valve actuator.

[0010] The diaphragm means may be configured to move towards the interior chamber in response to a reduction in pressure within the interior chamber.The diaphragm means may be configured to move towards the interior chamber in response to a user inhaling and thereby causing a reduction in pressure in the interior chamber.

[0011] The valve device can be moved between a fully open position providing maximum flow and a fully closed position providing minimum flow or no flow. The valve device can be continuously moved between the fully open position and the fully closed position to meter the flow of breathing gas. The valve actuator can control the position of the valve device.

[0012] The valve means or valve actuator may be configured such that movement of the diaphragm means towards the internal chamber moves the valve towards the open position.The valve means or valve actuator may be configured such that movement of the diaphragm means away from the internal chamber moves the valve means towards the closed position.

[0013] The diaphragm device may comprise a substantially impermeable membrane. The diaphragm device may be configured to deform due to a pressure differential between the first side and the second side. The diaphragm device may be sealed to the demand regulator around its periphery. The diaphragm device may be removable.

[0014] The diaphragm biasing spring may be configured to exert a biasing force on the diaphragm toward the interior chamber.

[0015] The diaphragm biasing spring may be configured to apply a pushing force to the diaphragm arrangement.The diaphragm biasing spring may be configured to apply a pulling force to the diaphragm arrangement.

[0016] The diaphragm biasing spring may be arranged to contact the diaphragm arrangement and to contact a spring seat of the demand adjuster so as to be compressed or deformed between the diaphragm arrangement and the spring seat to apply the biasing force.

[0017] The bias adjustment device may be configured to adjust the spacing between the spring seat and the diaphragm device, thereby adjusting the compression or deformation of the diaphragm bias spring.

[0018] The spring seat may be movable to adjust the spacing between the spring seat and the diaphragm arrangement.

[0019] In the case where the diaphragm biasing spring is configured to apply a pushing force to the diaphragm device, reducing the spacing between the spring seat and the diaphragm device can increase the biasing force. In the case where the diaphragm biasing spring is configured to apply a pulling force to the diaphragm device, increasing the spacing between the spring seat and the diaphragm device can increase the biasing force.

[0020] The spring seat may be disposed on a spring seat cap configured to substantially cover the first side of the diaphragm device, optionally wherein the spring seat cap includes one or more apertures therethrough.

[0021] The spring seat cap may include helical threads, and the demand adjuster or diaphragm cap may also include corresponding threads, configured to adjust the position of the spring seat cap relative to the diaphragm assembly, thereby adjusting the spacing between the spring seat and the diaphragm assembly.

[0022] Rotating the spring seat cap can adjust the gap between the spring seat and the diaphragm assembly. Clockwise rotation of the spring seat cap can reduce the gap. Counterclockwise rotation of the spring seat cap can increase the gap.

[0023] Adjusting the spacing and the biasing force can adjust the resting position of the diaphragm device, which in turn can adjust the resting position or balance of the valve device. Adjusting the resting position of the valve device can change the minimum flow rate of the valve device.

[0024] The diaphragm biasing spring may be a coil spring. The spring seat cap may be generally circular in plan view.

[0025] The bias adjustment device may further include a locking feature configured to lock the bias adjustment device to prevent adjustment of the spacing between the spring seat and the diaphragm device.

[0026] The demand regulator may further comprise a diaphragm cap configured to substantially cover the diaphragm device. The diaphragm cap may be configured to secure the diaphragm between the diaphragm cap and the housing.

[0027] The diaphragm device may include a peripheral sealing strip. The housing may include a first sealing seat, and the diaphragm cap may include a second sealing seat. The diaphragm cap may be fixed to the housing so as to press or fix the sealing strip of the diaphragm device between the first sealing seat and the second sealing seat.

[0028] The diaphragm cap may include a spring seat cap. The relative position of the spring seat cap and the diaphragm cap may be adjustable.

[0029] The demand regulator may further comprise a removable dust cover configured to cover the diaphragm device to protect the first side of the diaphragm device. The removable dust cover may comprise one or more apertures for allowing fluid communication between the ambient environment and the first side of the diaphragm device.

[0030] According to a second aspect, a respiratory mask for a breathing apparatus is provided, the respiratory mask comprising a demand regulator according to the first aspect.

[0031] According to a third aspect, there is provided a breathing apparatus comprising the demand regulator of the first aspect or comprising the breathing mask of the second aspect.

[0032] According to a fourth aspect, a demand regulator for a respiratory device is provided, the demand regulator comprising: a diaphragm device operatively connected to a valve device; a diaphragm biasing spring configured to apply a biasing force to the diaphragm device; and a bias adjusting device configured to adjust the compression or deformation of the diaphragm biasing spring, thereby adjusting the biasing force applied to the diaphragm device.

[0033] Any aspect may include any combination of features and / or limitations mentioned in combination with any other aspect above, unless such combinations of features are mutually exclusive. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Embodiments of the present invention will now be described by way of example with reference to the accompanying drawings, in which:

[0035] Figure 1 schematically illustrates a breathing apparatus according to an exemplary arrangement, the breathing apparatus comprising a breathing mask and a demand regulator;

[0036] Figure 2 schematically illustrates a breathing mask according to an exemplary arrangement, the breathing mask comprising a demand regulator; and

[0037] Figure 3 A cross-sectional view of a demand regulator according to an exemplary arrangement is schematically shown.

[0038] Like features in the drawings are indicated by like reference numerals. DETAILED DESCRIPTION

[0039] refer to Figure 1 , an exemplary breathing apparatus 10 is shown. The breathing apparatus 10 is a self-contained breathing apparatus (SCBA) and includes a support frame or back plate 12, a belt 14 for securing the SCBA to a user, a breathing gas cylinder 16, a breathing mask 18, a demand regulator 100 connectable to the breathing mask, and a pneumatic system 20 for delivering breathing gas from the cylinder 16 through a hose or flexible conduit 22 to the demand regulator 100, thereby delivering the breathing gas to the user wearing the mask 18 as needed. The breathing apparatus 10 may also include other components or systems not shown, including but not limited to electrical systems, monitoring systems, and communication systems.

[0040] In the illustrated arrangement, the breathing apparatus is a self-contained breathing apparatus (SCBA), but it will be appreciated that the demand regulator 100 may also be compatible with and adapted for use with other types of breathing apparatus, such as self-contained underwater breathing apparatus (SCUBA) and emergency escape breathing apparatus.

[0041] Figure 2A breathing mask 18 is shown that includes a demand regulator 100. As shown in more detail in the figure, a hose 22 of a pneumatic system 20 is connected to an inlet 101 of the demand regulator 100 to provide breathing gas from a gas cylinder 16. The pneumatic system 20 may include a first stage pressure reducer that reduces the pressure of breathing air from the gas cylinder, which may be stored at a pressure of several hundred bars, to an intermediate pressure for provision to the demand regulator 100 via the hose 22. The intermediate pressure may be too high to provide the gas directly to a user for breathing. As will be described in more detail below, the demand regulator 100 may also include a second stage pressure reducer that further reduces the pressure of the breathing air to a pressure suitable for delivery to the user for breathing. In other arrangements, more or less than two pressure reducers may be provided.

[0042] The demand regulator 100 is removably connected to the breathing mask 18. Figure 3 As shown in , the connection conduit 102 protrudes from the demand regulator 100 and is configured to be received in a corresponding connection opening in the mask 18 (not shown). One or more latches or locks can be provided to secure the demand regulator 100 to the respiratory mask 18. One or more buttons 107 can be provided on the demand regulator 100 to release the latches or locks, thereby enabling the demand regulator 100 to be disconnected from the mask 18. In some examples, the demand regulator 100 can be completely locked in place so that the demand regulator cannot move relative to the mask 18 when the mask and demand regulator are connected. In some examples, the demand regulator 100 can freely rotate relative to the respiratory mask 18 (e.g., about the central axis of the connection conduit 102) when the mask and demand regulator are connected.

[0043] Now go to Figure 3 , showing that along Figure 2 1. A side cross-sectional view of the demand regulator 100 taken along plane AA shown in FIG. The demand regulator is sometimes also referred to as a "lung demand valve" or LDV. The function of the demand regulator is to reduce the pressure of the gas delivered from the breathing gas cylinder through the pneumatic system 20 and the hose 22 (i.e., act as a second stage pressure reducer), and another function is to meter the flow of breathing gas delivered to the user wearing the breathing mask 18.

[0044] The demand regulator 100 comprises a housing 104 defining an internal chamber 106. The chamber 106 is used for pressure sensing. The internal chamber 106 is in communication with a valve arrangement 108 for controlling the flow of breathing gas into the internal passage 103 of the connecting conduit 102. The valve arrangement 108 receives breathing gas from the hose 22 of the pneumatic system 20 and, when opened, expands the breathing gas (thereby acting as a second stage pressure reducer) and discharges it into the internal passage 103, which is also in communication with the internal chamber 106. Figure 3 The dashed arrows in show an exemplary path of gas as it exits the valve device 108. During use, the valve device can be configured to provide a "positive pressure" (e.g., a pressure of 0-5 mbar above ambient pressure) in the internal chamber 106 and the internal conduit 103, and thus in the respiratory mask 18. This can be achieved by setting the valve device 108 in a slightly open position to allow gas to continuously flow into the internal chamber 106 and maintain the pressure within the internal chamber 106, the internal passage 103, and the respiratory mask 18 above ambient pressure, thereby making it impossible for ambient gas to enter the mask 18.

[0045] The demand regulator 100 includes a connecting conduit 102 extending from a housing 104 and defining an internal passage 103 through which breathing gases can pass to reach the breathing mask 18 when the connecting conduit 102 is received in a connecting opening located in the mask 18. The internal passage 103 is in fluid communication with an internal chamber 106. Both the connecting conduit 102 and the passage 103 are generally cylindrical. The outer surface of the connecting conduit 102 includes an annular sealing element 105 for sealingly engaging with the connecting opening in the mask 18. It will be appreciated that because the passage 103 is in communication with the mask 18, the pressure in the passage 103 and the internal chamber 106 decreases when the user inhales.

[0046] The demand regulator 100 also includes a diaphragm device 110. The diaphragm device 110 may be composed of a single layer, a single component, or a single material, or may include multiple layers, multiple components, and / or multiple materials. The diaphragm device 110 may be generally circular in plan view. The diaphragm device 110 is arranged to form a barrier between the internal chamber 106 and the surrounding environment. In other words, a first side of the diaphragm device 110 is exposed to the surrounding environment (and the ambient pressure), and a second side of the diaphragm device 110 is exposed to the internal chamber 106 (and the chamber pressure therein). The diaphragm device 110 is sealed around its periphery and includes an elastically deformable material, whereby the pressure difference between the ambient pressure and the chamber pressure causes the diaphragm device to move toward the internal chamber 106 in response to a decrease in pressure within the internal chamber 106, and to move away from the internal chamber 106 in response to an increase in pressure in the internal chamber 106. It will be appreciated that the diaphragm device 110 is configured to move toward the interior chamber in response to an inhalation by a user, thereby causing the pressure in the interior chamber to decrease, thereby causing the pressure differential across the diaphragm device 110 to increase.

[0047] The diaphragm device 110 may be removable, for example, for cleaning or replacement. The demand regulator 100 further includes a diaphragm cap 112 configured to substantially cover the diaphragm device 110 and the housing 104. The diaphragm cap 112 is configured to secure the diaphragm device 110 between the diaphragm cap 112 and the housing 104. To achieve this, the diaphragm device 110 includes a peripheral sealing strip 114, the housing 104 includes a first annular sealing seat 116, and the diaphragm cap includes a second annular sealing seat 118. The diaphragm cap 112 is secured to the housing 104, for example, by a threaded connection and the sealing strip 114 is arranged between the diaphragm cap and the housing so that the sealing strip 114 of the diaphragm device 110 is pressed or secured between the first and second sealing seats 116, 118, thereby securing and sealing the diaphragm device 110.

[0048] Turning now to the operation of the valve device 108, the valve device includes a valve actuator 120 for actuating the valve device 108. In this example, the valve actuator 120 takes the form of an actuating rod 120. The actuating rod 120 is pivotally connected to the housing 104 and to a valve member 122 of the valve device 108. The actuating rod 120 is rotated in a counterclockwise direction (in Figure 3 The pivotal movement of the valve member 122 (indicated by a solid arrow in the figure) causes the valve member 122 to move away from the valve seat 126 of the valve device 108, which in turn increases the flow of breathing gas through the valve device 108. The distal end portion of the valve actuation rod 120 contacts the diaphragm device 110, whereby the movement of the diaphragm in turn moves the actuation rod 120, thereby actuating the valve. A valve spring 124 is provided for biasing the valve member 122 toward the valve seat 126 (i.e., biasing the valve device 108 toward the closed position).

[0049] The diaphragm device 110 in this example includes a contact pad 128 made of a substantially rigid material. The contact pad 128 is configured to provide a more rigid contact point between the valve actuation stem 120 and the diaphragm device 110, thereby transmitting force therebetween. The actuation stem 120 may be actuated, for example, by a spring. Figure 3 1 is biased in the clockwise direction as shown in FIG. 1 to maintain contact between the actuation rod 120 and the contact pad 128 .

[0050] In this manner, the diaphragm device 110 is operatively connected to the valve device 108. Movement of the diaphragm device 110 toward the internal chamber 106 in turn pivots the actuating rod 120 and increases the spacing between the valve member 122 and the valve seat 126, thereby increasing the flow of gas through the valve device 108. It should be understood that when the forces (including pressures) applied to the diaphragm device 110 and the valve device 108 are balanced, the valve member 122 will be in an equilibrium position. In some examples, such as when positive pressure is not required, the equilibrium position can be a fully closed position in which the valve member 122 is sealed against the valve seat 126. In other examples, such as when positive pressure is required in the mask 18, the equilibrium position can be a slightly open position that allows some flow through the valve. The demand regulator 100 can also include a locking mechanism that mechanically urges the valve device 108 into the fully closed position regardless of other forces applied, which locking mechanism can be activated, for example, when the demand regulator is not in use.

[0051] The demand regulator 100 also includes a diaphragm biasing spring 130. The diaphragm biasing spring 130 is configured to apply a biasing force to the diaphragm device 110 toward the internal chamber 106. In this example, the diaphragm biasing spring 130 is a coil spring that is compressed between the diaphragm device 110 and the diaphragm cap 112, thereby applying a pushing force to the diaphragm device 110. It should be understood that other arrangements are possible, for example, the diaphragm biasing spring can be configured to apply a pulling force to the diaphragm device, and / or different types of springs or biasing members can be utilized. The diaphragm cap 112 includes a spring seat cap 134 that forms a spring seat 136 for one end of the diaphragm biasing spring 130. The other end of the diaphragm biasing spring 130 contacts the contact pad 128 of the diaphragm device 110. Therefore, the diaphragm biasing spring 130 is compressed between the spring seat cap 134 and the diaphragm device 110 to apply a biasing force to the diaphragm device 110.

[0052] It will be appreciated that the various forces applied to the diaphragm assembly 110 and valve assembly 108 may affect the balance or equilibrium position of these components. For example, if positive pressure is required, then balancing the various forces may be important to ensure proper gas flow through the valve assembly 108. Additionally, calibration of the demand regulator components may also be important to adjust the amount of force required to move the diaphragm assembly 110 so that the user can breathe freely without having to inhale too hard.

[0053] In order to adjust the biasing force and thus adjust the balance of the demand regulator 100, the demand regulator 100 also includes a biasing adjustment device 132, which is configured to adjust the compression of the diaphragm biasing spring 130 and thereby adjust the biasing force applied to the diaphragm device 110. The biasing adjustment device 132 is configured to adjust the spacing between the spring seat 136 and the diaphragm device 110, thereby adjusting the compression or deformation of the diaphragm biasing spring 130. Since the spring seat 136 is disposed on the spring seat cap 134, the spring seat cap 134 is configured to adjust the spacing between the spring seat 136 and the diaphragm device 110. The spring seat cap 134 is configured to substantially cover the first side of the diaphragm device 110. In addition, the spring seat cap 134 includes one or more holes 137 therethrough to allow fluid communication between the first side of the diaphragm device 110 and the surrounding environment.

[0054] In this example, reducing the spacing between the spring seat 136 and the diaphragm device 110 increases the biasing force. Likewise, increasing the spacing between the spring seat 136 and the diaphragm device 110 decreases the biasing force. In this example, movement of the spring seat 136 is achieved by disposing a spring seat cap 134 in an opening in the diaphragm cap 112, which is connected via a helical thread on the periphery of the spring seat cap 134 and a corresponding thread on the inner wall of the opening in the diaphragm cap 112. Therefore, by rotating the spring seat cap 134, the position of the spring seat cap 134 relative to the diaphragm cap 112 can be adjusted. It should be understood that rotating the spring seat cap 134 enables adjustment of the spacing between the spring seat 136 and the diaphragm device 110. In this example, clockwise rotation of the spring seat cap 134 causes the spacing to decrease and causes the biasing force to increase, while counterclockwise rotation of the spring seat cap 134 causes the spacing to increase and causes the biasing force to decrease.

[0055] It will be appreciated that adjusting the spacing and therefore the biasing force will adjust the resting position of the diaphragm device 110, which in turn will adjust the resting position or equilibrium of the valve device 108. It will be appreciated that adjusting the resting position of the valve device 108 may change the minimum flow rate of the valve device 108 or change the force used by the user to move the diaphragm device 110 by inhaling. More specifically, reducing the biasing force may increase the pressure difference across the diaphragm device 110 required to move the diaphragm device 110, while increasing the biasing force may decrease the pressure difference across the diaphragm device 110 required to move the diaphragm device 110. The biasing adjustment device 132 is provided to enable the biasing force to be adjusted, thereby adjusting the equilibrium or equilibrium position of the diaphragm device 110 and the valve device 108.

[0056] In this example, the diaphragm bias spring is a coil spring, and the spring seat cap 134 and the spring seat 136 are generally circular in a plan view. In this way, the spring seat cap 134 can be easily rotated while in contact with the bias spring 130 without damaging the bias spring 130.

[0057] In some examples, the bias adjuster 132 may also include a locking feature configured to lock the bias adjuster 132 to prevent adjustment of the spacing between the spring seat 136 and the diaphragm device 110. Thus, after the bias adjuster 132 is calibrated to provide the desired balance of the demand adjuster 100, the locking feature may be engaged to prevent accidental or intentional tampering, which may affect the calibration of the demand adjuster 100. In some examples, the locking mechanism may take the form of a grub screw, a detent mechanism, or some other feature that prevents adjustment of the bias adjuster 132. In some examples, after the bias adjuster 132 is adjusted to the proper position, the bias adjuster may be permanently secured, such as by gluing or welding.

[0058] Additionally, in this example, the demand regulator 100 further includes a removable dust cover 138. The dust cover is resilient and is configured to cover the diaphragm device 110, the diaphragm cap 112, and a majority of the housing 104 to protect the demand regulator, and in particular, to protect the first side of the diaphragm device 110. The dust cover 138 includes an aperture 140 for allowing fluid communication between the ambient environment and the first side of the diaphragm device 110.

[0059] The demand regulator of the present disclosure enables easier calibration of the demand regulator.Because the bias adjustment device can be adjusted via the external structure of the demand regulator housing, the calibration of the demand regulator can be adjusted without requiring extensive disassembly of the regulator.

[0060] It should be understood that the disclosed exemplary arrangement is one of many possible configurations for providing a biasing force to the diaphragm. In the case of using other biasing configurations, it should be understood that the principles of the present disclosure can be applied and adjusted to provide a biasing adjustment mechanism suitable for adjusting the biasing force applied to the diaphragm.

Claims

1. A demand regulator (100) for a breathing apparatus (10), the demand regulator comprising: a housing (104) defining an interior chamber (106); valve means (108) for controlling the flow of breathing gas into the internal chamber (106); a diaphragm device (110), a first side of the diaphragm device configured to be exposed to the surrounding environment, and a second side of the diaphragm device configured to be exposed to the internal chamber (106), the diaphragm device (110) being operatively connected to the valve device (108); a diaphragm biasing spring (130) configured to apply a biasing force to the diaphragm device (110); as well as A bias adjustment device (132) is configured to adjust the compression or deformation of the diaphragm bias spring (130), thereby adjusting the biasing force applied to the diaphragm device (110).

2. The demand regulator (100) according to claim 1, wherein: The diaphragm biasing spring (130) is configured to exert the biasing force on the diaphragm device toward the interior chamber (106).

3. The demand regulator (100) according to claim 1 or 2, wherein: The diaphragm biasing spring (130) is arranged to contact the diaphragm device (110) and to contact a spring seat (136) of the demand regulator (100) so as to be compressed or deformed between the diaphragm device (110) and the spring seat (136) to apply the biasing force.

4. The demand regulator (100) according to claim 3, wherein: The bias adjustment device (132) is configured to adjust the spacing between the spring seat (136) and the diaphragm device (110), thereby adjusting the compression or deformation of the diaphragm bias spring (130).

5. The demand regulator (100) according to claim 4, wherein: The spring seat (136) is movable so as to adjust the distance between the spring seat (136) and the diaphragm device (110).

6. The demand regulator (100) according to claim 5, wherein: The spring seat (136) is disposed on a spring seat cap (134), the spring seat cap being configured to substantially cover the first side of the diaphragm device (110), optionally wherein the spring seat cap (134) includes one or more holes (137) passing through the spring seat cap.

7. The demand regulator (100) according to claim 6, wherein: The spring seat cap (134) includes helical threads, and the demand adjuster (100) also includes corresponding threads, which are configured to adjust the position of the spring seat cap (134) relative to the diaphragm device (110), thereby adjusting the spacing between the spring seat (136) and the diaphragm device (110).

8. The demand regulator (100) according to any one of claims 6 and 7, wherein: The diaphragm biasing spring (130) is a coil spring, and wherein the spring seat cap (134) is generally circular in plan view.

9. The demand regulator (100) according to any one of claims 4 to 8, wherein: The bias adjustment device (132) also includes a locking feature configured to lock the bias adjustment device (132) to prevent adjustment of the spacing between the spring seat (136) and the diaphragm device (110).

10. The demand regulator (100) according to any one of the preceding claims, wherein The demand regulator (100) further comprises a diaphragm cap (112) configured to substantially cover the diaphragm device (110), wherein the diaphragm cap (112) is optionally configured to secure the diaphragm device between the diaphragm cap (112) and the housing (104).

11. The demand regulator (100) according to claim 10, wherein: The diaphragm cap (112) includes the spring seat cap (134), and the relative position of the spring seat cap (134) and the diaphragm cap (112) is adjustable.

12. The demand regulator (100) according to any of the preceding claims, further comprising a removable dust cover (138), the removable dust cover being configured to cover the diaphragm device (110) to protect the first side of the diaphragm device (110), and the removable dust cover (138) comprising one or more holes (140) for allowing fluid communication between the surrounding environment and the first side of the diaphragm device (110).

13. A breathing mask (18) for a breathing apparatus (10) comprising a demand regulator (100) according to any one of the preceding claims.

14. A breathing apparatus (10) comprising a demand regulator (100) according to any one of claims 1 to 11 or a breathing mask (18) according to claim 13.

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