A ventilation apparatus

Abstract

The invention relates to a ventilation apparatus comprising a blower (1) arranged to generate an air flow (AF) along an air duct (2) and an air flow meter arranged to measure the air flow generated by the blower. The air flow meter comprises a differential pressure gauge (3), and a measuring element (4) arranged to extend in the air duct (1) in a transverse direction to the air flow (AF) and to connect to the differential pressure gauge (3). The measuring element (4) comprises a primary air channel (5) and a secondary air channel (6).

Description

[0001] A VENTILATION APPARATUS

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to a ventilation apparatus especially for civil protection shelters, and more particularly to a ventilation apparatus as described in the preamble of the independent claim.

[0004] BACKGROUND OF THE INVENTION

[0005] In the prior art ventilation apparatuses, the air flow meter typically has an adjustable choke inside the measuring funnel in order to achieve a large pressure difference. The choke requires adjustment in order to obtain a sufficiently large pressure difference in the air flow meter. It also makes the structure of the air flow meter more complicated.

[0006] BRIEF DESCRIPTION OF THE INVENTION

[0007] An object of the present invention is to provide a ventilation apparatus having an air flow meter which can measure small and large air flows without compromising the stability of the air flow meter and still providing accurate results.

[0008] The objects of the invention are achieved by a ventilation apparatus which is characterized by what is stated in the independent claim. The preferred embodiments of the invention are disclosed in the dependent claims.

[0009] The invention is based on the idea of having two separate channels in the air flow meter, which is arranged inside an air duct, and which the channels capture the air flow flowing through the air duct from different sides of the air flow meter, allowing the pressure difference to be measured.

[0010] A ventilation apparatus according to the invention comprises a blower arranged to generate an air flow along an air duct and an air flow meter arranged to measure the air flow generated by the blower. The air flow meter comprises a differential pressure gauge, and a measuring element disposed inside the air duct on a downstream side of the blower. The measuring element is arranged to extend in the air duct in a transverse direction to the air flow and to connect to the differential pressure gauge. The measuring element comprises a primary air channel and a secondary air channel. The primary air channel is arranged to open on the upstream side of the air flow through a primary opening, and to form a flow connection to the differential pressure gauge to convey air from the primary opening through the primary air channel to the differential pressure gauge. The secondary air channel is arranged to open on the downstream side of the air flow through a secondary opening and to form a flow connection from the secondary opening through the secondary air channel to the differential pressure gauge.

[0011] In other words, the air flow meter comprising the differential pressure gauge and the measuring element are provided in connection with each other such that the measuring element is placed inside the air duct and the differential pressure gauge gauge extends outside the air duct such that the measurement readings shown by the differential pressure gauge can be seen from outside the air duct. The measuring element comprises the primary air channel and the secondary air channel which are parallel and extend in the measuring element in a transverse direction to the air flow flowing through the air duct. The primary air channel and the secondary air channel are preferably arranged on top of each other in the measuring element such that the air flow meets first the primary air channel and then the secondary air channel. The measuring element is arranged in the air duct such that the air flow passes the measuring element when flowing along the air duct, and preferably the air flow passes the measuring element on both sides of the measuring element as it is arranged to extend in the air duct transverse to the air flow. As the primary air channel is arranged to open on the upstream side of the air flow through a primary opening, then the primary air channel is preferably on the upstream side on the measurement element, and the secondary air channel is on the downstream side on the measurement element as it opens on the downstream side of the air flow. The upstream side of the air flow is the air flow flowing between the blower and the measuring element and the downstream side of the air flow is the air flow that has passed the measuring element in the air duct.

[0012] According to the invention the measuring element comprises a wing element arranged to extend away from an outer surface of the measuring element in a plane transverse to the air duct such that the wing element is arranged to separate an upstream side and a downstream side of the measuring element. The primary opening is arranged on the upstream side of the measuring element and the secondary opening is arranged on the downstream side of the measuring element.

[0013] In other words, the wing element is arranged to extend from the outer surface of the measuring element so that the air flow passing by the measuring element along the outer surface of the measuring element meets the wing element which prevents the air flow further flowing along the outer surface of the measuring element. This stabilizes the air flow in the area of the primary opening and the secondary opening so that the air entering into the primary air channel and the secondary air channel. The upstream side of the measuring element is the side of the measuring element facing towards the blower and the downstream side of the measuring element is the side of the measuring element facing away from the blower. The wing element is arranged to extend in a plane that is transverse to the air duct and preferably in such a way that the plane is perpendicular to the air flow flowing along the air duct from the blower.

[0014] According to the invention the wing element is arranged at the measuring element such that it extends along a longitudinal direction of the measuring element and comprises a first wing element area and a second wing element area. The second wing element area is arranged to extend further away from the outer surface of the measuring element than the first wing element area, and the second wing element area is arranged to prevent air flow flowing along the outer surface of the measuring element at the secondary opening.

[0015] In other words, the wing element extends along the longitudinal direction of the measuring element, in which direction the primary air channel and the secondary air channel also extend. This means that the wing element protrudes from the wing element along the longitudinal direction of the wing element and extends away from the outer surface of the measuring element such that the first wing element area and the second wing element area extend in the plane of the cross-section of the air duct such that the air flow flowing through the air duct meets the wing element preferably perpendicularly. The wing element extends away from the outer surface of the measuring element in transverse direction to the air flow and has a larger wing element area in connection with the measuring element where the secondary opening is arranged. The primary opening and the secondary opening are arranged in the measuring element at such a distance from each other such that the measuring element provided in the air duct and extending across the air duct captures the air flow flowing through the air duct at different points of the air duct in the transverse direction of the air duct. This means that the primary opening and the secondary opening are arranged at a distance from each other in the longitudinal direction of the measuring element. The longitudinal direction is the direction in which the primary air duct and the secondary air duct extend.

[0016] According to the invention the primary air channel comprises a primary supply chamber, a buffer chamber, and a primary supply channel. The primary supply channel extending from the primary supply chamber to the buffer chamber such that a flow communication is formed between the primary supply chamber and the buffer chamber through the primary supply channel, and the supply chamber further forming a flow connection with the differential pressure gauge.

[0017] In other words, the primary air channel comprises the primary supply chamber which is in a flow connection with the primary supply channel extending from the primary supply chamber. The primary supply channel is further in a flow connection with the buffer chamber such that the primary supply channel extending from the primary supply chamber to the buffer chamber. The buffer chamber being a closed chamber such that the flow connection between the primary channel and the buffer chamber is the only flow connection of the buffer chamber.

[0018] According to the invention the primary opening is provided in connection with the primary supply channel in the primary air channel.

[0019] In other words, the primary opening is provided in the primary air channel to the primary supply channel arranged to extend between the primary supply chamber and the buffer chamber.

[0020] According to the invention the primary opening is provided in connection with the primary supply channel in the primary air channel such that the primary opening opens in a transverse direction to the air flow.

[0021] In other words, the primary opening is arranged to open at least partially towards the wall of the air duct such that the air flow flowing along the air duct comes sideways to the primary opening. Sideways meaning that the air flow does not flow perpendicularly or directly into the primary opening.

[0022] According to the invention the primary opening is provided in connection with the primary supply channel in the primary air channel such that the primary opening is closer to the primary supply chamber than the buffer chamber.

[0023] In other words, the primary opening is closer to the differential pressure gauge than the end of the primary air channel, which is at the opposite end to the differential pressure gauge. The primary opening is arranged in the primary supply channel preferably such that the primary opening is closer to the primary supply chamber than to the center of the primary supply channel.

[0024] According to the invention the primary supply channel having a smaller volume than the primary supply chamber, or alternatively the primary supply channel having a smaller volume than the buffer chamber, or alternatively the primary supply channel having a smaller volume than the primary supply chamber and the buffer chamber.

[0025] In other words, the air flow coming through the primary opening enters into the primary supply channel wherefrom it flows through the primary supply channel on both directions, i.e., to the buffer chamber and to the primary supply chamber which is in flow connection with the differential pressure gauge. Since the buffer chamber is a closed chamber, it is filled with air and acts as a buffer for the incoming air, equalizing the variation of the pressure difference in the primary air channel. The buffer chamber is chamber-like, i.e., it has a larger volume than the primary supply channel. In the primary air channel of the measuring element, the variation of the pressure difference has been equalized by means of different volumes of the parts of the primary air channel, so that the meter display of the differential pressure gauge is made to work stably.

[0026] According to the invention the primary supply channel having a smaller diameter than the diameter of the primary supply chamber, or alternatively the primary supply channel having a smaller diameter than the diameter of the buffer chamber, or alternatively the primary supply channel having a smaller diameter than the diameter of the primary supply chamber and the diameter of the buffer chamber.

[0027] In other words, the primary supply channel into which the air flow enters through the primary opening has a smaller diameter than the buffer chamber or than the primary supply chamber or both. This means that air entering the primary supply channel flows further to the primary supply chamber and to the buffer chamber for filling them. When the buffer chamber is filled with the air, it acts as a buffer pushing the air toward the primary supply chamber and to the differential pressure gauge, thereby equalizing the pressure difference.

[0028] According to the invention the secondary air channel comprises a secondary supply chamber, a pre-chamber and a secondary supply channel, the secondary supply channel extending from the pre-chamber to the secondary supply chamber such that a flow communication is formed between the prechamber and the secondary supply chamber through the secondary supply channel, and the secondary supply chamber further forming a flow connection with the differential pressure gauge.

[0029] In other words, the secondary air channel comprises the secondary supply chamber which is in a flow connection with the secondary supply channel extending from the secondary supply chamber. The secondary supply chamber is in flow connection with the differential pressure gauge. The secondary supply channel is further in a flow connection with the pre-chamber such that the secondary supply channel extending from the secondary supply chamber to the pre-chamber.

[0030] According to the invention the secondary opening is provided in connection with the pre-chamber in the secondary air channel.

[0031] In other words, the secondary air channel comprising the pre-chamber which is in flow communication with the secondary supply channel extending from the pre-chamber and further the secondary supply channel is in flow communication with the secondary supply chamber extending from the secondary supply channel. The pre-chamber having the secondary opening for the air to enter into the secondary air channel so that the air flows from the pre-chamber through the secondary supply channel to the secondary supply chamber which in turn is in flow connection with the differential pressure gauge.

[0032] According to the invention the secondary opening is provided in connection with the pre-chamber in the secondary air channel such that the secondary opening opens in the direction of the air flow in the air duct on the downstream side of the air flow.

[0033] In other words, the secondary opening faces in the direction of the air flow on the downstream side. In still other words, the secondary opening opens away from the blower in the air duct.

[0034] According to the invention the secondary opening is provided in connection with the pre-chamber in the secondary air channel such that the secondary opening is furthest away from the secondary supply channel.

[0035] In other words, the secondary opening is preferably arranged at the end of the pre-chamber which is furthest away from the secondary supply channel such that the air entering through the secondary opening flows through the entire prechamber before arriving to the secondary supply channel.

[0036] According to the invention the secondary supply channel having a smaller volume than the secondary supply chamber, or alternatively the secondary supply channel having a smaller volume than the pre- chamber, or alternatively the secondary supply channel having a smaller volume than the secondary supply chamber and the pre-chamber.

[0037] In other words, the air flow coming through the secondary opening enters into the pre-chamber so that it flows from the pre-chamber through the secondary supply channel to the secondary supply chamber. The pre-chamber having larger volume than the secondary supply channel extending from the pre- chamber is first filled with air which then flows through the secondary supply channel equalizing the pressure difference. Since the secondary supply chamber having larger volume than the secondary supply channel, it causes air to flow through the secondary supply channel.

[0038] According to the invention the secondary supply channel having a smaller diameter than the diameter of the secondary supply chamber, or alternatively the secondary supply channel having a smaller diameter than the diameter of the pre-chamber, or alternatively the secondary supply channel having a smaller diameter than the diameter of the secondary supply chamber and the prechamber.

[0039] In other words, the air enters into the pre-chamber having the secondary opening and flows from the pre-chamber into the secondary supply channel. The secondary supply channel having smaller diameter than the prechamber means that air flows faster into the secondary supply channel, where the speed levels off as it heads towards the secondary supply chamber. This equalizes the pressure in the secondary air channel.

[0040] The air duct that has been disclosed here in connection with the measuring element is preferably a tubular air duct that has a side wall forming the air channel along which the air flow flows in the air duct. The measuring element preferably extends across the air duct from a side wall to the opposite side wall and particularly preferably through the middle part of the air duct. The differential pressure gauge is preferably connected to the measuring element such that the main part of the differential pressure gauge is provided outside the air duct and preferably on the outer surface of the air duct.

[0041] An advantage of the invention is that the differential pressure gauge measures the air flow flowing through the air duct with the help of the pressure difference and the pressure difference is stabilized so that the differential pressure gauge shows both small and large air flows with precise and stable.

[0042] BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The invention is described in detail by means of specific embodiments with reference to the enclosed drawings, in which

[0044] Figure 1 shows the ventilation apparatus according to the invention;

[0045] Figure 2 shows the air flow meter according to the invention;

[0046] Figure 3 shows the air flow meter as shown in figure 2 as seen from other side; Figures 4a shows the air flow meter according to the invention; and Figures 4b and 4c show the measuring element as seen from different angles.

[0047] DETAILED DESCRIPTION OF THE INVENTION

[0048] Figure 1 shows the ventilation apparatus according to the invention, in which the air flow AF generated in a blower 1 is flowing through an air duct 2. A measuring element 4 connected to a differential pressure gauge 3 is provided in connection with the air duct 2. The arrows show the flow direction of the air flow AF. It must be understood that the illustration is simplified and the blower 1 is provided for the sake of clarity in the middle of the air duct 2. The differential pressure gauge 3 is provided in connection with the air duct 2 such that at least part of it is outside the air duct 2 so that the display showing the air flow is visible outside the air duct 2. The measuring element 4 is provided inside the air duct 2 such that the air flow AF passes the measuring element 4 preferably on both sides of the measuring element 4. This can be seen in more detailed in figure 2 showing that the measuring element 4 is provided in the middle of the cross section of the air duct 2, extending from the wall of the air duct to the opposite wall. The measuring element 4 has a first end 4a connected to the differential pressure gauge 3 and a second end 4b which is preferably connected to the wall of the air duct 2. Figure 1 also shows that the measuring element 4 comprises a wing element 7 protruding from an outer surface of the measuring element 4 in a plane transverse to the flow direction of the air flow AF. The wing element 7 divides the measuring element 4 into a downstream side and an upstream side, the upstream side of the measuring element 4 is the side which is on the upstream side of the air flow AF, i.e., the side of the measuring element 4 which faces toward the blower 1, i.e., the upstream side of the airflow is the part where the air flow is after the blower and before reaching the measuring element 4.

[0049] Figure 2 shows the air flow meter according to the invention, in which the first end 4a of the measuring element 4 is connected to the differential pressure gauge 3 such that a flow communication is provided between the measuring element 4 and the differential pressure gauge 3. The figure 2 shows the measuring element 4 as seen along the line A-A as expressed in the figure 1 thereby showing the measuring element 4 as seen from the downstream side. The measuring element 4 comprises a secondary air channel 6 extending along the measuring element 4 inside the measuring element 4. For the sake of clarity different parts of the secondary air channel 6 are not visible in this cut-out of the downstream side of the measuring element 4. The secondary opening 16 is arranged at the opposite end of the secondary air channel 6 in relation to the differential pressure gauge 3. The wing element 7 is arranged to protrude from the outer surface of the measuring element 4 and has a larger wing element area on that part of the measuring element 4 where the secondary opening 16 is provided than in the part where the primary opening 15 is arranged. The air flow is arranged to pass the measuring element 4 on both sides of the measuring element 4 and the downstream side of the air flow enters to the secondary air channel 6 through the secondary opening 16. The larger wing element area protects and stabilises the entrance of the air flow through the secondary opening 16.

[0050] Figure 3 shows the air flow meter as shown in figure 2 as seen from the other side, which is the upstream side of the air flow or in other words the upstream side of the measuring element 4 which faces toward the blower 1 wherefrom the air flow AF comes. The figure 3 shows the measuring element 4 as seen along the line B-B as expressed in the figure 1 thereby showing the measuring element 4 as seen from the upstream side. The measuring element 4 comprises a primary air channel 5 extending along the measuring element 4 inside the measuring element 4. For the sake of clarity different parts of the primary air channel 5 are not visible in this cut-out of the downstream side of the measuring element 4. The primary opening 15 is arranged closer to the first end 4a of the measuring element 4 than the second end 4b of the measuring element 4. The wing element 7 is arranged to protrude from the outer surface of the measuring element 4 and has a smaller wing element area on that part of the measuring element 4 where the primary opening 15 is provided than in the part where the secondary opening 16 is arranged. The primary opening 15 is towards the wall of the air duct 2 and thus the air flow AF flows in the area of the primary opening 15 in a lateral direction relative to the primary opening 15. The air flow is arranged to pass the measuring element 4 on both sides of the measuring element 4 and the upstream side of the air flow enters to the primary air channel 5 through the primary opening 15.

[0051] Figures 4a shows the air flow meter according to the invention as a cutout version of the air flow meter shown in figure 1, i.e., as seen from side. The figure 4a shows the primary air channel 5 and the secondary air channel 6 in more detailed. The primary air channel 5 extends on the upstream side of the measurement element 4, i.e., on the side of the measurement element 4 which faces toward the blower 1. The primary air channel 5 comprises the primary supply chamber 51, the primary supply channel 53 and the buffer chamber 52 such that the primary supply channel 53 is connected from its one end to the primary supply chamber 51 and from its other end to the buffer chamber 52 which are in a flow communication with each other. The primary opening 15 is arranged at the primary supply channel 52 preferably closer to the primary supply chamber 51 than to the buffer chamber 52. The secondary air channel 6 extends parallel to the primary air channel 5 and comprises a secondary supply chamber 61, a secondary supply channel 63 and a pre-chamber 62 such that the secondary supply channel 63 is connected from its one end to the secondary supply chamber61 and from its other end to the pre-chamber 62 which are in a flow communication with each other.

[0052] Figures 4b and 4c show the measuring element as seen from different angles. The figure 4b shows the measuring element 4 as seen from the downstream side so that the secondary air channel 6 is shown with the secondary supply chamber 61, the secondary supply channel 63 and the pre-chamber 63. At the end of the secondar air channel 6 in the pre-chamber 63 is the secondary opening 16. The wing element 7 is arranged to protrude from the outer surface of the measuring element 4. The wing element 7 comprises a first wing element area 7a and a second wing element area 7b. The second wing element area 7b is larger than the first wing element area 7a and is provided at the area of the pre-chamber 62 so that it stabilises the air flow around the secondary opening 16.

[0053] The figure 4c shows the measuring element 4 as seen from the first end 4a of the measuring element 4 which is connected to the differential pressure gauge 3. The primary air channel 5 and the secondary air channel 6 are provided on top of each other such that the primary air channel 5 is on the upstream side of the measuring element 4, i.e., on the side facing toward the blower 1 in the air duct 2. The wing element 7 comprising the first wing element 7a and the second wing element 7b protrude from the outer surface of the measuring element 4.

[0054] The invention has been described above with reference to the examples shown in the figures. However, the invention is in no way restricted to the above examples but may vary within the scope of the claims.

Claims

CLAIMS1. A ventilation apparatus comprising a blower (1) arranged to generate an air flow (AF) along an air duct (2), c h a r a c t e r i z e d in that the ventilation apparatus further comprises an air flow meter arranged to measure the air flow generated by the blower, the air flow meter comprises: a differential pressure gauge (3), and a measuring element (4) disposed inside the air duct (2) on a downstream side of the blower (1), the measuring element (4) is arranged to extend in the air duct (1) in a transverse direction to the air flow (AF) and to connect to the differential pressure gauge (3), the measuring element (4) comprises a primary air channel (5) and a secondary air channel (6), the primary air channel (5) is arranged to open on the upstream side of the air flow (AF) through a primary opening (15), and to form a flow connection to the differential pressure gauge (3) to convey air from the primary opening (15) through the primary air channel (5) to the differential pressure gauge (3), and the secondary air channel (6) is arranged to open on the downstream side of the air flow (AF) through a secondary opening (16) and to form a flow connection from the secondary opening (16) through the secondary air channel (6) to the differential pressure gauge (3).

2. A ventilation apparatus according to claim 1, c h a r a c t e r i z e d in that the measuring element (4) comprises a wing element (7) arranged to extend away from an outer surface of the measuring element (4) in a plane transverse to the air duct (2) such that the wing element (7) is arranged to separate an upstream side and a downstream side of the measuring element (4), the primary opening (15) is arranged on the upstream side of the measuring element (4) and the secondary opening (16) is arranged on the downstream side of the measuring element (4).

3. A ventilation apparatus according to claim 2, c h a r a c t e r i z e d in that the wing element (7) is arranged at the measuring element (4) such that it extends along a longitudinal direction of the measuring element (4) and comprises a first wing element area (7a) and a second wing element area (7b), the second wing element area (7b) is arranged to extend further away from the outer surface of the measuring element (4) than the first wing element area (7a), and the second wing element area (7b) is arranged to prevent air flow (AF) flowing along the outersurface of the measuring element (4) at the secondary opening (16).

4. A ventilation apparatus according to any of claims 1 - 3, characterized in that the primary air channel (5) comprises a primary supply chamber (51), a buffer chamber (52) and a primary supply channel (53), the primary supply channel (53) extending from the primary supply chamber (51) to the buffer chamber (52) such that a flow communication is formed between the primary supply chamber (51) and the buffer chamber (52) through the primary supply channel (53), and the supply chamber (51) further forming a flow connection with the differential pressure gauge (3).

5. A ventilation apparatus according to claim 4, characterized in that the primary opening (15) is provided in connection with the primary supply channel (53) in the primary air channel (5).

6. A ventilation apparatus according to claim 4 or 5, characterized in that the primary opening (15) is provided in connection with the primary supply channel (53) in the primary air channel (5) such that the primary opening (15) opens in a transverse direction to the air flow (AF).

7. A ventilation apparatus according to any of claims 4 - 6, characterized in that the primary opening (15) is provided in connection with the primary supply channel (53) in the primary air channel (5) such that the primary opening (15) is closer to the primary supply chamber (51) than the buffer chamber (52).

8. A ventilation apparatus according to any of claims 4 - 7, characterized in that the primary supply channel (53) having a smaller volume than the primary supply chamber (51), or the primary supply channel (53) having a smaller volume than the buffer chamber (52), or the primary supply channel (53) having a smaller volume than the primary supply chamber (51) and the buffer chamber (52).

9. A ventilation apparatus according to any of claims 4 - 8, characterized in that the primary supply channel (53) having a smaller diameter than the diameter of the primary supply chamber (51), or the primary supply channel (53) having a smaller diameter than the diameter of the buffer chamber (52), or the primary supply channel (53) having a smaller diameter than the diameter of the primary supply chamber (51) and the diameter of the buffer chamber (52).

10. A ventilation apparatus according to any previous claim, characterized in that the secondary air channel (6) comprises a secondary supply chamber (61), a pre-chamber (62) and a secondary supply channel (63), the secondary supply channel (63) extending from the pre-chamber (62) to the secondary supply chamber (61) such that a flow communication is formed between the pre-chamber (63) and the secondary supply chamber (61) through the secondary supply channel (63), and the secondary supply chamber further forming a flow connection with the differential pressure gauge (3).

11. A ventilation apparatus according to claim 10, characterized in that the secondary opening (16) is provided in connection with the pre-chamber (62) in the secondary air channel (6).

12. A ventilation apparatus according to claim 10 or 11, characterized in that the secondary opening (16) is provided in connection with the pre-chamber (62) in the secondary air channel (6) such that the secondary opening (16) opens in the direction of the air flow (AF) in the air duct (2) on the downstream side of the air flow (AF).

13. A ventilation apparatus according to any of claims 10 - 12, characterized in that the secondary opening (16) is provided in connection with the pre-chamber (62) in the secondary air channel (6) such that the secondary opening (16) is furthest away from the secondary supply channel14. A ventilation apparatus according to any of claims 10 - 13, characterized in that the secondary supply channel (63) having a smaller volume than the secondary supply chamber (61), or the secondary supply channel (63) having a smaller volume than the pre-chamber (62), or the secondary supply channel (63) having a smaller volume than the secondary supply chamber (61) and the pre-chamber (62).

15. A ventilation apparatus according to any of claims 8 - 14, characterized in that the secondary supply channel (63) having a smaller diameter than the diameter of the secondary supply chamber (61), or the secondary supply channel (63) having a smaller diameter than the diameter of the pre-chamber (62), or the secondary supply channel (63) having a smaller diameter than the diameter of the secondary supply chamber (61) and the pre-chamber (62).

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