EP3883656A1

EP3883656A1 - Powered air personal respirator

Info

Publication number: EP3883656A1
Application number: EP19809898.0A
Authority: EP
Inventors: John Boffey
Original assignee: World Wide Welding Ltd
Current assignee: World Wide Welding Ltd
Priority date: 2018-11-23
Filing date: 2019-11-22
Publication date: 2021-09-29
Also published as: WO2020104815A1; GB201819120D0; GB2579210A

Abstract

A powered air personal respirator (10), comprises a housing (26), an oxygen sensor (28) carried by the housing (26), for measuring the content of oxygen in the surrounding atmosphere, and an alarm, wherein the powered air respirator (10) is arranged to trigger the alarm when the content of oxygen falls below a threshold value. The invention also relates to a method of calibrating the powered air respirator (10) by connecting a tubular connector (36) to the sensor (28), blowing air into the tubular adapter (36), obtaining a first reading of oxygen content in exhaled air, and comparing the first reading to oxygen content values expected in the exhaled air to confirm that the device is correctly calibrated.

Description

Powered Air Personal Respirator

This invention relates to powered air personal respirator and a method of calibrating a powered air personal respirator.

Powered air respirators can be used when welding. Welding is a process of permanently joining two materials, usually of a similar type, for instance two metals, using high temperature. It is known that the welding process produces fumes which, depending on the type of material to be joined, may be harmful to an operator of welding equipment. For this reason, welding is typically performed in an open, well ventilated environment, with continuous access to fresh, non- contaminated air. However, such an environment is not always readily available or possible.

Powered air respirators in accordance with the Standard EN 12941 can be used to improve of the quality of the air supply to the operator of welding equipment, if welding must be performed in an environment having limited access to fresh air. Such systems typically include a battery powered fan unit capable of drawing air from the contaminated environment, filtering said air, and discharging it via a hose into a helmet/hood worn by the operator of the welding equipment.

In a first aspect of the present invention there is provided :

a powered air personal respirator, comprising :

a housing;

an oxygen sensor carried by the housing, for measuring the content of oxygen in the surrounding atmosphere; and,

an alarm;

wherein the powered air respirator is arranged to trigger the alarm when the content of oxygen measured by the oxygen sensor falls below a threshold value.

In a second aspect of the present invention there is provided a pump unit for a powered air personal respirator, comprising :

a housing defining an inlet and an outlet;

a fluid pump drawing air through the inlet and exhausting filtered air through the outlet; an air filter disposed at the inlet;

an alarm to alert the user such that the alarm is arranged to be triggered when the content of oxygen measured by the oxygen sensor falls below a threshold value.

The powered air respirator may be suitable for use in environments where oxygen supplies are quickly depleting, for example as a result of combustion or chemical reaction. Such environments are found in pharmaceutical, foundry/melting, welding, construction, painting, transportation applications, although the use in other circumstances where the oxygen supply is quickly depleting is also possible. The powered air personal respirator is preferably a welding powered air personal respirator.

Advantageously, the powered air respirator of the invention equipped with an oxygen sensor sounds an alarm signal when the oxygen content in the surrounding atmosphere drops below a predetermined safe threshold. This warning system improves safety of the working equipment and has a positive impact on the health of the operator of the e.g. welding equipment. Early detection of a low oxygen level minimises the risk of the operator collapsing or suffocating. Knowing that the oxygen content is too low to be safe, the operator can quickly leave the unsafe area and move to a safer environment. The threshold value of the powered air respirator or of the pump unit may be no more than 20.5%, or may be no more than 19.5%, or may be no more than 17%.

The powered air respirator or the pump unit may comprise a control circuit electrically connected to the sensor. The control circuit may be configured to record measurements from the sensor and compare them against the threshold value. The control circuit may be arranged to trigger the alarm if the content of oxygen drops below the threshold value.

The powered air respirator or the pump unit may also include a display for displaying the measured oxygen content, which may be built into the housing.

Advantageously, the display shows the oxygen content immediately after performing the measurement. This visual cue enables the operator of the welding equipment to quickly make a decision whether to stay or leave their workspace, thereby increasing their safety.

In a third aspect of the present invention, there is provided a kit comprising the aforementioned powered air personal respirator and a tubular adapter, a first end of the adapter being arranged to interfit with an inlet of the oxygen sensor, and a second end being arranged to fit into or onto a user's mouth such that a user can blow into the second end in order to blow air through the adapter into the oxygen sensor to test the alarm.

Because the oxygen content of exhaled air is expected to be low enough to set off the alarm, this enables the alarm system to be tested easily and effectively.

The kit may include means to indicate the detected oxygen level to the user. Said means may be a display to display the percentage of oxygen in the atmosphere. The kit may further include a connector to connect the display to the respirator and thereby to an output from the oxygen sensor.

In a fourth aspect of the present invention there is provided a method of calibrating a powered air personal respirator, comprising the steps of:

providing a powered air personal respirator or a pump unit according to a previous aspect of the invention;

providing a tubular adapter connectable to the sensor at a first end and arranged to fit in or onto a user's mouth at a second end;

connecting the first end of the tubular adapter to an inlet of the sensor; blowing air into the tubular adapter through the second end;

obtaining a first reading of oxygen content in exhaled air;

comparing the first reading to oxygen content values expected in the exhaled air to confirm that the device is correctly calibrated.

Oxygen sensors are usually calibrated by third parties, prior to their installation on equipment. Therefore, in practice, the user of such a device has no possibility to re-calibrate the sensor, or check if it is working correctly. Such sensors may show erroneous readings if they have been exposed to extreme conditions, such as very high/low temperature, very high/low humidity, and high particulate concentration in air. Advantageously then, the fourth aspect of the invention provides an improved method of calibrating oxygen sensors in a powered air respirator. The method may further comprise the step of blowing air into the tube for the second time, after holding breath for a duration of time so as to obtain a second reading of oxygen content in exhaled air. The second reading may then be compared to the first reading.

The method may include a step of checking that the alarm is triggered when the oxygen content is measured to be below the threshold value. Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which :

Figure 1 is a schematic view of a powered air respirator in an embodiment of the invention showing the pump unit in cross-section;

Figure 2 is a perspective view of the pump unit of the powered air respirator of the embodiment;

Figure 3 is a partial front elevation in cross-section view of the pump unit of the powered air respirator;

Figure 4 is a side elevation of a pump unit in a second embodiment having a built in screen; and

Figure 5 is a schematic side elevation in cross-section of a pump unit in a third embodiment having an oxygen sensor in a different location.

With reference to the drawings, a powered air respirator for welding 10 in the first embodiment comprises a helmet 12, a pump unit 14 and a hose 16.

The helmet 12 provides a cover for a user's face and mouth whilst the user is performing welding. The helmet 12 insulates the head and face of the user from external atmosphere. The helmet 12 includes an opening through which air may be introduced into the helmet 12.

The pump unit 14 comprises a housing 26, an inlet 22, an outlet 24, a filter 20 and a fluid pump 18. The housing 26 carries components of the pump unit 14, including the filter 20 and the fluid pump 18, as well as sensors and controllers. The housing 26 defines the said inlet 22 and outlet 24.

A flow path F extends through the inlet 22 to the filter 20 and on to the fluid pump 18 and out through the outlet 24. The outlet 24 is formed of a female connector. The connector is a bayonet connector. The hose 16 is flexible and may be extendable. The hose 16 has a connector at each end, the connector at one end being a male connector to mate with the female connector of the pump unit outlet 24.

The fluid pump 18 is battery powered and includes a fan to drive the fluid through the pump unit 14 along the flow path F.

With reference to Figures 2 and 3, the pump unit 14 includes an oxygen sensor 28, a control circuit in the form of a processor 32, and a digital port 34 and an alarm 48.

The oxygen sensor 28 has an inlet 30. The inlet 30 is partially exposed to the surrounding atmosphere.

The oxygen sensor 28 is capable of measuring oxygen content in the surrounding atmosphere. Such a sensor 28 is capable of collecting data with regard to the content of oxygen in the surrounding atmosphere, which data may then be processed by the processor 32 of the pump unit 14. The processor 32 is connected to an alarm 48, which has a loudspeaker to create an audible alarm sound. With reference to Figure 2, the powered air respirator 10 is part of a kit for welding which further comprises a display 42 and a tubular connector 36.

The tubular connector 36 comprises a flexible tube 40 and a connector 38. The connector 38 is adapted to fit onto the outlet 30 of the oxygen sensor 28. The connector 38 is made of an elastomeric material and is pushed onto the oxygen sensor outlet to form a seal therewith.

The display 42 is connectable to the digital port 34 by means of a digital connector cable 44 with a jack plug 46.

In use, the pump unit 14 is connected to the hose 16 at the outlet 24, the connection between the housing and the pump unit is established by the bayonet connector. A similar connection is established between the hose 16 and the helmet 12.

Fresh air is delivered to the helmet 12 by the pump unit 14 through the hose 16.

The motion of air is driven by the fluid pump 18, which sucks contaminated air into the pump unit 14 through the inlet 22. The filter 20 purifies the air, which then flows through the outlet 24 into the hose 16. The hose 16 delivers the purified air through the opening into the helmet 12.

The outlet 30 of the oxygen sensor 28 is continuously exposed to the surrounding atmosphere. In use, the oxygen sensor 28 may perform continuous measurements, or it may perform intermittent measurements at a time interval specified by the user of the equipment. The system is set up in such a way as to sound the alarm 48 to give the user of the equipment an indication of oxygen levels dropping dangerously low. In standard conditions, the oxygen content is usually 21%. A powered air respirator 10 can be set up in such a way as to indicate to the user whenever the oxygen level drops below 21%. The safe threshold may be set at below 19% or alternatively it may be set at below 17%.

The information with regard to safe thresholds and current oxygen content readings are stored on the processor 32. The processor 32 receives data from the oxygen sensor 28, then processes it in order to determine whether the current oxygen content readings are less or more than the predetermined threshold levels. The content of oxygen can be displayed on the display 42 which is electrically connected to the processor 32. The alarm 48 is sounded when the processor 32 establishes that the current level of oxygen is below the safe threshold.

The user may wish to determine whether the oxygen sensor is working correctly. To that end, the tubular adapter 36 can be attached to the inlet 30 of the oxygen sensor 28 by means of the connector 38. The other end 50 of the tubular adapter 36 fits into the user's mouth.

By blowing into the tube 36, and knowing that air exhaled by the user will have a lower oxygen content which should trigger the alarm, the fidelity of operation of the oxygen sensor system can be evaluated. In normal conditions, atmospheric air consists of 78% nitrogen, 21% oxygen, and 1% other gases. Exhaled air consists of 78% nitrogen, 16-17% oxygen, 4-5% C02 and 1% other gases.

The user who blows into the tube 36 should expect the readings to be in the region of 16-17% of the oxygen content. To test the sensor further, the user may hold their breath for a duration of time in order to decrease the oxygen content in the exhaled air still further. Generally, the longer the breath is held, the lower the oxygen content should become. Thus, the user should see a drop significantly below 16-17% of oxygen in exhaled air upon holding their breath for a duration of time. If the system is working correctly, the user should also receive an alarm signal indicating that the oxygen level has reduced below what is a safe threshold.

The current oxygen content reading appears on the display 42. This gives the user a visual indication of the oxygen content. If the reading is below the safe threshold, the value displayed on the display 42 is accompanied by the sound of the alarm 48.

Thus, the powered air respirator 10 of the embodiment sounds an alarm when the oxygen content in the surrounding atmosphere drops below a predetermined safe threshold. Knowing that the oxygen content is too low to be safe, the operator can quickly leave the unsafe area and move to a safer environment.

Advantageously, the display 42 shows the oxygen content immediately after performing the measurement. This visual cue enables the operator of the welding equipment to quickly make a decision whether to stay or leave their workspace, thereby increasing their safety.

The tubular adapter 36 enables the functioning of the system to checked quickly and easily before use.

In a second embodiment, shown in Figure 4, the pump unit 14 has the screen 42 built into the housing 26. Therefore, in this embodiment the digital connector 44, as shown in Figure 2, is absent.

In an alternative embodiment as shown in Figure 5, the oxygen sensor 28 is disposed in the flow path F. The oxygen sensor 28 can be arranged in such a way that the inlet 30 is exposed to the air flowing into the inlet 22 of the pump unit 14 and along the flow path F. Thus, the oxygen sensor 28 is mounted in front of the air pump inlet 22. In this way, new air will flow over the oxygen sensor as air is drawn into the pump unit 14 by the pump 18, so that any change in the atmospheric oxygen is quickly detected. It is envisaged that the oxygen sensor 28 may be disposed anywhere along the flow path F, so long as the location of the sensor 28 does not interfere with the operation of the fluid pump 18.

The alarm signal can be in the form of an audio signal, but in an alternative embodiment the loudspeaker may be supplemented or replaced by another form of alarm such as a vibration producing device creating tactile feedback or a visual alarm such as a flashing light.

The connector can be of any type, and need not be a bayonet connector, but any other suitable connector is possible.

The digital port 34 and the plug 46 can be of any suitable alternative kind, such as HDMI or USB, although other ports and plugs are also possible. In another embodiment, there could be a mouthpiece on the end 50 of the tube 40 to go over a user's mouth.

Claims

1. A kit comprising a powered air personal respirator and a tubular adapter, the powered air personal respirator, comprising :

a housing;

an oxygen sensor carried by the housing, for measuring the content of oxygen in the surrounding atmosphere;

an alarm; and

the tubular adapter having a first end arranged to interfit with an inlet of the oxygen sensor, and a second end arranged to fit into or onto a user's mouth such that a user can blow into the second end in order to blow air through the adapter into the oxygen sensor to test the alarm;

wherein the powered air personal respirator is arranged to trigger the alarm when the content of oxygen measured by the oxygen sensor falls below a threshold value.

2. The kit as claimed in claim 1, wherein the threshold value is no more than 20.5%.

3. The kit as claimed in claim 1, wherein the threshold value is no more than 19.5%.

4. The kit as claimed in claim 1, wherein the threshold value is no more than 17%.

5. The kit as claimed in claim 1, 2, 3, or 4, further comprising a control circuit electrically connected to the sensor, wherein the control circuit is configured to record measurements from the sensor and compare them against the threshold value.

6. The kit as claimed in claim 5, wherein the control circuit is arranged to trigger the alarm if the content of oxygen drops below the threshold value.

7. The kit as claimed in any preceding claim further comprising a display for displaying the measured oxygen content.

8. The kit as claimed in claim 7, wherein the display is built into the housing.

9. The kit as claimed in any of the claims 1 to 8, wherein the kit includes means to indicate the detected oxygen level to the user.

10. The kit as claimed in claim 9, wherein the means is a display to display the percentage of oxygen in the atmosphere, and the kit further includes a connector to connect the display to the respirator and thereby to an output from the oxygen sensor.

11. A method of calibrating a powered air personal respirator, comprising the steps of:

providing a powered air personal respirator or pump unit as claimed in any preceding claim;

obtaining a first reading of oxygen content in exhaled air;

12. The method as claimed in claim 11 further comprising the step of blowing air into the tube for the second time, after holding breath for a duration of time so as to obtain a second reading of oxygen content in exhaled air.

13. The method as claimed in claim 12 further comprising the step of comparing the second reading to the first reading.

14. The method as claimed in claim 11, 12 or 13 further comprising the step of checking that the alarm is triggered when the oxygen content is measured to be below the threshold value.