Arrangement for measuring differential pressure on a radial ventilator

Abstract

The present invention relates to an arrangement for differential pressure measurement on a radial fan (102), comprising a differential pressure sensor (114), wherein the arrangement comprises a nozzle (100) arranged on an air inlet side of the radial fan (102) or the air inlet side is designed in a nozzle-like manner, wherein the nozzle (100) has an inlet cross-section (E) which, in a conical section (106), merges into a passage cross-section (D) which is reduced compared to the inlet cross-section (E), wherein a slot-shaped measuring opening (110) is arranged in the region of the passage cross-section (D) or adjacent to the passage cross-section (D), and the measuring opening (110) opens into a closed measuring chamber (112) which is at least partially formed by the nozzle (100), and the measuring chamber (112) is spatially connected to the differential pressure sensor (114), wherein the differential pressure sensor (114) is further spatially connected to the environment (104).The invention also relates to a corresponding nozzle (100).

Description

[0001] The invention relates to an arrangement for measuring differential pressure on a radial fan.

[0002] Radial fans are used particularly in ventilation units with and without heat recovery, but are not limited to this.

[0003] According to the prior art, document EP 2 508 811 B1 discloses a device for determining the volume flow delivered by a fan. It is provided that a closed annular channel with a plurality of openings is arranged in the region of an inlet nozzle of the fan, and the annular channel is connected to a pressure difference sensor. The pressure difference sensor is further connected to a reference tube for detecting the ambient pressure.

[0004] Against this background, the object of the present invention was to provide an improved arrangement for differential pressure measurement on a radial fan compared to the prior art. In addition to more reliable measurement data, problems caused by the accumulation of condensate and contamination should be solved. The inventive solution should be easy to install and maintain.

[0005] The invention is based on an arrangement for measuring differential pressure on a radial fan, comprising a differential pressure sensor and a nozzle arranged on an air inlet side—in other words, the suction side—of the radial fan. Alternatively, the air inlet side of the radial fan can be designed as a nozzle. The air drawn in by the radial fan flows through the nozzle.

[0006] According to the invention, the nozzle has a typically circular inlet cross-section, which, in a conical section, transitions to a passage cross-section that is smaller than the inlet cross-section. A slot-shaped measuring opening is arranged in the region of the passage cross-section, and the measuring opening opens into an otherwise closed measuring chamber. The slot-shaped measuring opening is accordingly designed in the shape of a circular arc.

[0007] The conical section of the nozzle enables air to be sucked in with low turbulence and thus in aerodynamically advantageous manner.

[0008] A differential pressure sensor is spatially connected to the measuring chamber, so that the pressure in the area of the passage cross-section is indirectly measured by the differential pressure sensor via the measuring opening and the measuring chamber. The differential pressure sensor has two inputs between which the pressure difference is determined.

[0009] The differential pressure sensor is spatially connected to the environment via the second input to detect the ambient air pressure, so that the pressure difference between the pressure in the measuring space and the ambient air pressure can be determined.

[0010] Accordingly, the differential pressure can be advantageously measured, for example to control the performance of the radial fan.

[0011] The core of the invention is that the nozzle has a slot-shaped measuring opening which is connected to the measuring chamber.

[0012] The slot-shaped measuring opening allows the static pressure to be measured at the reduced cross-section, which also occurs in the measuring chamber due to the connection. This pressure corresponds to the air volume flow delivered by the radial fan.

[0013] Preferably, the slot-shaped measuring opening is arranged at the narrowest point of the nozzle so that the detectable differential pressure is maximum.

[0014] The slot-shaped measuring opening effectively prevents contamination or clogging of the measuring opening with condensation. This allows for reliable pressure data to be recorded and transmitted to the differential pressure sensor.

[0015] Features of advantageous embodiments of the invention are defined in particular in the subclaims, wherein further advantageous features, embodiments and configurations can also be gathered by the person skilled in the art from the above explanations and the following discussion.

[0016] According to a preferred embodiment of the invention, the slot-shaped measuring opening extends at an angle between 30 and 140 degrees, particularly preferably at an angle between 70 and 110 degrees. Since the measuring opening is arranged in the region of the passage cross-section, the measuring opening is thus designed in the shape of a circular arc. This specified angle has proven advantageous for measuring the pressure and prevents the measuring opening from becoming clogged with dirt and condensation, and self-cleaning effects are also achieved. In the particularly preferred embodiment, the rigidity of the nozzle body is also advantageously provided, thus ensuring sealing with the radial fan housing.

[0017] According to a further preferred embodiment of the invention, the slot-shaped measuring opening is arranged in the area of the fan outlet. It has been found that when the measuring opening is arranged in the passage cross-section in the fan outlet sector, the pressure difference to the ambient air pressure is particularly high, so that particularly well-evaluable pressure data can be recorded.

[0018] According to a further preferred embodiment of the invention, the nozzle is attached to the inlet side of a housing of the radial fan and sealed to the radial fan housing, and the measuring chamber is formed by a recess in the nozzle body. This allows the nozzle to be easily assembled, disassembled, and accordingly inspected, cleaned, and replaced if necessary.

[0019] The nozzle is preferably made of plastic using the injection molding process and is attached to the radial fan housing and preferably screwed to it.

[0020] The measuring chamber is formed by a recess in the nozzle body and accordingly by an otherwise closed cavity.

[0021] According to a preferred embodiment of the invention, the measuring chamber is further delimited by the radial fan housing opposite the nozzle body. This advantageously delimits the measuring chamber, in addition to the recess in the nozzle body, by the opposite surface of the radial fan housing. Appropriately arranged seals naturally ensure that the pressure in the measuring chamber can be accurately measured by the differential pressure sensor.

[0022] According to a further preferred embodiment of the invention, the differential pressure sensor is arranged on or in the radial fan housing and connected to the measuring chamber via a connecting line. Due to this arrangement, the ambient air pressure can be directly detected by the differential pressure sensor. The connection between the differential pressure sensor and the measuring chamber can advantageously be established via a pipe and / or a hose. The nozzle is preferably designed with a connection for a connecting line.

[0023] According to a preferred embodiment of the invention, a seal between the nozzle and the radial fan housing is provided by corresponding, concentrically formed tongue and groove systems formed on the nozzle and / or radial fan housing. Optionally, the respective tongue and groove system can also comprise several parallel grooves and tongues. O-ring seals can also advantageously be used as tongues. The tongue and groove system according to the invention enables an efficient seal between the nozzle body and the radial fan housing.

[0024] According to a preferred embodiment of the invention, the measuring opening extends to the lowest point of the measuring chamber. This advantageously ensures the drainage of condensate and, if present, dirt from the measuring chamber via the measuring opening to the passage opening.

[0025] The invention further provides a nozzle for arrangement on the inlet side of a radial fan. The nozzle has an inlet cross-section that, in a conical section, transitions to a passage cross-section that is smaller than the inlet cross-section. A slot-shaped measuring opening is arranged in the region of the passage cross-section or adjacent to the passage cross-section. The measuring opening opens into a closed measuring chamber at least partially formed by the nozzle. Furthermore, the nozzle has a connecting line connected to the measuring chamber or a connection for a connecting line.

[0026] Accordingly, the invention further provides a nozzle which can be advantageously used to form an advantageous arrangement according to the invention for differential pressure measurement on radial fans.

[0027] The invention further provides a method for measuring differential pressure on a radial fan using a differential pressure measuring arrangement. According to the invention, the pressure in the measuring chamber and the ambient air pressure are detected by the differential pressure sensor, and a pressure difference is determined between the two pressures.

[0028] Since the pressure difference corresponds to the air volume flow delivered by the fan, the air volume flow can be determined using a corresponding characteristic curve. The determined pressure difference can thus be advantageously used to measure the air volume flow and, if necessary, to control the performance of the radial fan using a control unit.

[0029] The present invention is further illustrated and explained below with reference to exemplary embodiments shown in the figures. Fig. 1a radial fan from the air inlet side with a nozzle, Fig. 2a perspective view of the Fig. 1 , Fig. 3the radial fan housing made of Fig. 1 without nozzle, Fig. 4 a nozzle from the air inlet side, Fig. 5 a nozzle from the side opposite the air inlet side, Fig. 6 a perspective view of the Fig. 4 , Fig. 7a perspective view of the Fig. 5 , Fig. 8 a detailed view of the measuring chamber in the spiral casing of the radial fan, Fig. 9 a sectional view of the measuring chamber with spiral casing and nozzle, and Fig. 10 another detailed view of the Fig. 9 .

[0030] In the accompanying drawings and the explanations to these drawings, corresponding or related elements are marked with corresponding reference symbols where appropriate.

[0031] The Fig. 1shows a radial fan 102 from the air inlet side - in other words from the suction side - with a nozzle 100 attached to it with screws 122.

[0032] The nozzle 100 has a passage cross-section D on its inside, through which the air is drawn in by the radial fan 102. The radial fan 102 comprises an impeller (not shown) with, for example, backward-curved impeller blades.

[0033] The nozzle 100 further comprises a slot-like measuring opening 110 in the region of the passage cross-section D. The air flow conveyed by the radial fan 102 leaves the radial fan 102 through the outlet opening 118. The circular arc-shaped (approximately 90 degrees), slot-like measuring opening 110 is advantageously arranged in the region of the fan outlet 118, since the greatest difference to the ambient air pressure 104 occurs here due to the asymmetrical air intake.

[0034] Furthermore, the connecting line 116 or its connection to the actual differential pressure sensor (not shown) is located in this area. The connecting line 116 and thus the differential pressure sensor are guided through the measuring chamber (112 in Fig. 3 ) is connected to the slot-like measuring opening 110. Accordingly, the pressure at the measuring opening 110 can be indirectly measured by means of the differential pressure sensor through the spatial (pneumatic) connection.

[0035] In Fig. 2 is a perspective view of the Fig. 1 shown.

[0036] In Fig. 3 is the radial fan housing 102 of the Fig. 1 without the Fig. 1 known nozzle 100 is again shown from the air inlet side.

[0037] The measuring chamber 112 located behind the nozzle 100 can be seen. Separating struts 125 delimit the measuring chamber, which form a tongue-and-groove connection running in the radial direction with separating struts 115 (see further figures) of the nozzle 100. Tangentially extending separating struts 126 are formed on the lower side of the measuring chamber 112. The tangentially extending separating struts 126 also form a tongue-and-groove connection with corresponding separating struts 115 of the nozzle 100. However, by extending tangentially rather than radially, the drainage of any condensate from the measuring chamber 112 is improved, as explained in detail below.

[0038] The nozzle 100 is preferably made of plastic by injection molding. The nozzle 100 transitions in a conical section 106 from an inlet cross-section E into the passage cross-section D in an aerodynamically advantageous manner. The conical section 106 advantageously enables a low-turbulence intake of the air. Otherwise, refer to the description. Fig. 1 referred to.

[0039] The Fig. 3 shows the Fig. 2 illustrated nozzle 100 from the side opposite the air inlet side, i.e. the side that rests against the radial fan housing 102.

[0040] Fig. 4 to 7 show the nozzle 100 isolated in different views. Fig. 4 shows the nozzle in plan view from the air inlet side, Fig. 5 in top view of the opposite side. Figs. 6 and 7 show perspective views of the Fig. 4 or 5.

[0041] On the outer circumferential edge of the nozzle 100 and adjacent to the passage cross-section D, sealing areas 120 are provided, which are designed as a tongue and groove system 120. The measuring chamber 112 is formed, as it were, as a recess in one sector of the nozzle 100. The measuring chamber 112, which is connected to the measuring opening 110 and the connecting line 116, is thus delimited by the inner and outer sealing areas 120 and two sealingly designed separating struts 115, 115' and, due to the positioning of the nozzle 100 on the wall of the radial fan housing, is thus designed as a closed space. The measuring chamber 112 is connected to the connecting line 116 via a connecting opening 116'.

[0042] Furthermore, stiffening ribs 124 are provided in the area of the passage cross-section D of the nozzle 100, which stiffen the nozzle 100 and thus seal it against the radial fan housing 102. The stiffening ribs 124 can also extend beyond the measuring opening 110.

[0043] Since the measuring opening 110 extends to the bottom of the measuring chamber 112, any condensate that forms can drain through the measuring opening 110. This is particularly facilitated by the fact that the separating strut 115' at the lower edge runs tangentially rather than radially outward, thus improving the drainage of the condensate. The direction of extension of the two separating struts 115, 115' is therefore different, namely radial and tangential.

[0044] Fig. 8shows a detailed view of the measuring chamber 112 in the spiral casing of the radial fan 112. It can be seen that the measuring chamber 112 is located approximately between the 9 o'clock and 11 o'clock positions, namely approximately in the area of the fan outlet 118. This maximizes the measurable differential pressure.

[0045] The measuring chamber 112 is defined by differently aligned separating struts 125, 126. The tangential alignment of the separating struts 126 at the lower end of the measuring chamber 112 ensures a particularly efficient discharge of any condensate in the flow direction F, as shown in detail in Fig. 9 and 10 can be seen.

[0046] Between the separating struts 115, 125 and 115', 126, a radially extending tongue and groove connection with a sealing effect is formed, as can be seen from the Fig. 9 and 10 can be seen in detail. List of reference symbols

[0047] 100Nozzle, nozzle body 102Radial fan, radial fan housing 104Environment 106Conical section 110Measuring opening 112Measuring chamber, recess in the nozzle body 115, 115'Separating struts 116Connecting line 118Fan outlet, outlet opening 120Seal, tongue and groove system 122Screw 124Stiffening rib 125Separating struts 126Separating struts DPassage cross-section, edge of the passage cross-section EInlet cross-section, edge of the inlet cross-section LAir flow

Claims

1. An arrangement for measuring differential pressure on a radial fan (102), comprising a differential pressure sensor (114), wherein the arrangement comprises a nozzle (100) arranged on an air inlet side of the radial fan (102) or the air inlet side is designed in a nozzle-like manner, wherein the nozzle (100) has an inlet cross-section (E) which, in a conical section (106), merges into a passage cross-section (D) which is reduced compared to the inlet cross-section (E), wherein a slot-shaped measuring opening (110) is arranged in the region of the passage cross-section (D) or adjacent to the passage cross-section (D), and the measuring opening (110) opens into a closed measuring chamber (112) which is at least partially formed by the nozzle (100), and the measuring chamber (112) is spatially connected to the differential pressure sensor (114), wherein the differential pressure sensor (114) is further spatially connected to the environment (104).

2. Arrangement for differential pressure measurement on a radial fan (102) according to claim 1, wherein the slot-shaped measuring opening (110) preferably extends at an angle between 30 and 140 degrees, particularly preferably at an angle between 70 and 110 degrees.

3. Arrangement for differential pressure measurement according to claim 2, wherein the slot-shaped measuring opening (110) is arranged in the region of the fan outlet (118).

4. Arrangement for differential pressure measurement on a radial fan (102) according to one of the preceding claims, wherein the nozzle (100) is attached to the inlet side of a housing (102) of the radial fan (102) and is sealed to the radial fan housing (102) and the measuring chamber (112) is formed by a recess in the nozzle body (100).

5. Arrangement for differential pressure measurement according to claim 4, wherein the measuring chamber (112) is further delimited by the radial fan housing (102) opposite the nozzle body (100).

6. Arrangement for differential pressure measurement according to one of the preceding claims, wherein the differential pressure sensor (114) is arranged on or in the radial fan housing (102) and is connected to the measuring chamber (112) by a connecting line (116).

7. Arrangement for differential pressure measurement according to one of the preceding claims, wherein a seal between the nozzle (100) and the radial fan housing (102) is provided by concentrically formed tongue and groove systems (120) formed on the nozzle (100) and / or radial fan housing (102) and corresponding to one another.

8. Arrangement for differential pressure measurement according to one of the preceding claims, wherein the measuring opening (110) extends to the lowest point of the measuring chamber (112).

9. Arrangement for differential pressure measurement according to one of the preceding claims, wherein for sealing the measuring chamber (112) between the nozzle (100) and the radial fan housing (102) by means of mutually corresponding tongue and groove systems (115, 115', 125, 126) formed on the nozzle (100) and the radial fan housing (102) on both sides of the measuring chamber (112) are arranged, wherein the direction of extension of the two tongue and groove systems (115, 115', 125, 126) is different with respect to a center of the nozzle.

10. Arrangement according to claim 9, wherein one of the two tongue and groove systems (115,125) runs radially and the other (115',126) runs tangentially.

11. Nozzle (100) for arrangement on an inlet side of a radial fan (102), wherein the nozzle (100) has an inlet cross-section (E) which, in a conical section (106), merges into a passage cross-section (D) which is reduced compared to the inlet cross-section (E), wherein a slot-shaped measuring opening (110) is arranged in the region of the passage cross-section (D) or adjacent to the passage cross-section (D), and the measuring opening (110) opens into an otherwise closed measuring chamber (112) which is at least partially formed by the nozzle (100), and the nozzle (100) has a connecting line (116) connected to the measuring chamber (112) or a connection for a connecting line (116).

12. Nozzle (100) or arrangement for differential pressure measurement according to one of the preceding claims, wherein the nozzle (100) has a radial and a tangentially extending separating strut (115, 115') for delimiting the measuring chamber (112).

13. Method for differential pressure measurement on a radial fan (102) by means of an arrangement for differential pressure measurement according to one of the preceding claims, wherein the pressure in the measuring chamber (112) and the pressure in the environment are detected by the differential pressure sensor (114) and a pressure difference is determined between the two pressures, wherein the pressure difference is used to detect the air volume flow and, if necessary, to control the power of the radial fan (102) by means of a control unit.

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