CN1688251A - Scrubber - Google Patents

Abstract

A scrubber for eliminating NO from air flowing through the scrubber, comprising a housing (1) having at least one inlet hole (2) and an outlet hole (4) and which is comprising filtering material (6). A second outlet hole (9) is provided in the housing (1) at a position situated at a distance from the first outlet hole (4) and any inlet hole (2) so that the air leaving the second outlet hole (9) will have flown at least through a depth of the filtering material (6) substantially corresponding to the depth of the filtering material (6) for the air flowing from the inlet hole (2) to the first outlet hole (4).

Description

Scrubber

technical field

The present invention relates to a scrubber for removing a component from air flowing through the scrubber.

Background technique

The known scrubber comprises a housing having at least one inlet opening and one outlet opening and including filter material. Scrubbers can be used, for example, in any device that requires e.g. nitric oxide-free air, e.g. for calibration, in measuring nitric oxide in air, especially in exhaled air, or in any other gas mixture in the horizontal device. In this case, the subjects inhaled air through a scrubber that filtered the nitric oxide out of the air. The flow rate of the air is, for example, about 1-10 liters/second.

Preferably there is a return valve positioned between the inlet/outlet of the device and the outlet of the scrubber through which the subject inhales/exhales so that exhaled air does not pass through the scrubber to reach the device any detection part of the .

When providing a zero reference or functional control for the sensing portion of the device, use a small stream of air devoid of a component, such as nitric oxide, and add it between the outlet of the scrubber and the return valve. One such problem is the potential for leaking return flow to mix with zero reference air through the return valve. This would compromise the accuracy of the zero measurement.

This is of course true for any filtration that removes a component from the air. It is therefore an object of the present invention to provide a scrubber which safely permits a zero reference airflow to flow reliably from the scrubber and also to the air inhaled by the tester which is filtered of this component.

Contents of the invention

This object is achieved by a scrubber according to claim 1 .

The advantage of this solution is that in the event of a leak or rupture of the return valve, the thickness of the filter material is still large enough to filter the air and make the system safe. This solution also has the advantage that the return valve can be a common mechanical device suitable for large flow rates, which is inexpensive, instead of an electrically controlled valve that needs to control small flow rates.

Another problem with known scrubbers is that the outlet is adapted to high flow rates, which means that there is a large "dead zone" at the outlet where there is air stagnation, as a zero reference or operationally controlled flow A long time must pass before it is determined that the air has flowed through the scrubber.

According to an embodiment of the invention, the second outlet is smaller than the first outlet, whereby the "dead zone" at the second outlet is minimized resulting in a very efficient system in which to confirm that the zero reference flow has safely passed the scrubber Less air needs to flow through the scrubber.

Preferably a scrubber is used to filter nitric oxide out of the air.

A problem with known nitric oxide scrubbers is that they include carbon filters to remove nitric oxide. However, these scrubbers are not suitable for long-term use. They quickly lose their ability to excrete nitric oxide when exposed to moisture, even at the levels of ambient humidity normally present. Another disadvantage is that they require large volumes to remove nitric oxide at the high flow rates and concentrations typically encountered in urban environments.

It is therefore an object of the present invention to provide a small scrubber which is suitable for long-term use. A solution to this problem is a scrubber consisting of potassium permanganate KmnO ₄ or potassium permanganate combined with an appropriate amount of carbon. The advantage of this material is that it reacts with nitrogen monoxide and forms manganese dioxide. It maintains its filterability in wet conditions, actually better than in dry conditions.

Description of drawings

Embodiments of the scrubber of the present invention will be described below in conjunction with the accompanying drawings, wherein:

Figure 1. Shows a cross-sectional view of an embodiment of a scrubber according to the invention.

Figure 2. Shows a terminal side view of the scrubber of Figure 1 with an inlet hole.

Figure 3. Shows a perspective view of the scrubber of Figure 1 .

Detailed ways

The scrubber of the invention comprises a housing 1 having at least one inlet orifice 2, and a first outlet orifice 4 on a terminal side 5 opposite the inlet terminal side 3, in the embodiment shown Several small inlet holes 2 are distributed on the side 3 of the terminal. In the housing 1 there is a filter material 6 .

Between the housing 1 and the filter material 6 there is a particle filter 7 at the inlet hole 2 and the first outlet hole 4 to prevent particles of the filter material 6 from leaving the scrubber through the holes 2,4.

The scrubber in the illustrated embodiment has a cylindrical wall 8 between the terminal sides 3, 5, although other shapes are of course also conceivable. On the wall 8 there is a second outlet opening 9 . This hole 9 is also internally protected by a particle filter 7 in order to prevent particles of the filter material 6 from leaving the scrubber through the second hole 9 . In the embodiment shown, air from the inlet hole 2 flows through the filter material 6 through the channel 10 to the second outlet hole 9 .

Preferably, the first outlet hole 4 is designed for an air throughput of about 1-10 liters/second and the second outlet hole 9 is designed for a throughput of about 0.5-50 ml/s.

In order to ensure that the air leaving the second outlet hole 9 has passed through a sufficient thickness of the filter material 6 there is no inlet hole 2 adjacent the second outlet hole 9 on the terminal side 3 . The air must pass through the filter material 6 of sufficient thickness like this, for example this thickness air corresponds at least substantially to the thickness of the filter material that air passes when passing between the inlet hole 2 and the first outlet hole 4, said thickness ensures a certain composition , such as nitric oxide, are filtered from the air.

In order to ensure that air flows from the inlet hole 2 to the second outlet hole 9 instead of flowing from the first outlet hole 4 to the second outlet hole 9, a return valve 11 can be arranged in the first outlet hole 4 or outside the extension of the outlet hole 4 .

As a safety measure, the second outlet hole 9 should also be arranged at a certain distance from the first outlet hole 4 in case the backflow valve 11 leaks. The air must pass through the filter material 6 of sufficient thickness like this, this thickness corresponds substantially to the thickness that the air passes when passing between the inlet hole 2 and the first outlet hole 4, and this thickness ensures that components, such as nitric oxide, can be removed from the air. filter in.

If the component to be removed is nitric oxide, the filter material 6 is preferably potassium permanganate KMnO ₄ in granular form or potassium permanganate combined with an appropriate level of carbon. The particle size may be 1/8-1/128 inch and preferably 1/32-1/64 inch. In a typical urban environment it is preferred that the concentration of nitric oxide in the air exiting any of the outlet holes 4, 9 is less than 5 ppb.

The invention is not limited to the embodiments shown and described, but any changes and modifications come within the scope of protection of the appended claims.

Claims (12)

1. A scrubber for removing a component from air flowing through said scrubber, comprising a housing (1) having at least one inlet orifice (2) and an outlet Hole (4) and comprises filter material (6), it is characterized in that: the second outlet hole (9) is arranged in housing 1 and the first outlet hole (4) and any inlet hole (2) are separated by a certain distance position, whereby the air coming out from the second outlet hole (9) has at least passed through a thickness of the filter material (6) which at least substantially corresponds to the flow of air from the inlet hole (2) to the first outlet hole (4) The thickness of the filter material (6) passed. 2. The scrubber according to claim 1, wherein the second outlet hole (9) is designed to have a smaller air throughput than the first outlet hole (4). 3. The scrubber according to claim 1 or 2, characterized in that: several inlet holes (2) are distributed on the terminal side (3) of the housing (1), and the terminal side (3) is connected to The terminal side (5) where the first outlet hole (4) is located is opposite to. 4. The scrubber according to claim 1, 2 or 3, characterized in that: the second outlet hole (9) is arranged on the wall (8) of the housing (1), and the wall (8) is Between the two terminal sides (3, 5). 5. A scrubber according to any one of the preceding claims, characterized in that there is no inlet hole adjacent to the second outlet hole (9) on the terminal side (5) including the first outlet hole (4), The air thus passes through at least a thickness of the filter material (6) which substantially corresponds to the thickness of the filter material (6) through which the air flows through the first outlet opening (4). 6. A scrubber according to any one of the preceding claims, characterized in that there is no return valve (11) in the first outlet hole (4). 7. A scrubber according to any preceding claim, wherein the scrubber is used to filter nitric oxide. 8. The scrubber according to claim 7, characterized in that: wherein the filter material (6) is potassium permanganate KMnO ₄ or potassium permanganate combined with an appropriate amount of carbon. 9. A scrubber as claimed in claim 7 or 8, wherein the scrubber filters nitric oxide levels to less than 5 ppb. 10. The scrubber according to any one of the preceding claims, wherein the particulate filter (7) is provided in the housing (1) at least at the inlet hole (2) and the first and second outlet holes ( 4, 9), to prevent the filter material (6) from leaking from the scrubber. 11. The scrubber according to any one of the preceding claims, wherein the flow rate through the first outlet hole (4) is about 1-10 liters/second and the flow rate through the second outlet hole (9) is About 0.5-50 ml/sec. 12. A scrubber according to any preceding claim, wherein the particle size of the filter material is in the range 1/8 - 1/128 inch, preferably 1/32 - 1/64 inch.