System and method in connection with a sash of a fume cupboard

Abstract

The invention relates to a system in connection with a sash (10) of a fume cupboard (2), the system including a sash (10) adapted to be vertically movable, which sash (10) is supported by two or more suspension elements (12) passing through pulleys (16) on one or more counterweights (14), and the system comprising a motor (20), which motor (20) is connected to at least two suspension elements (12) via a shaft (18), and which sash (10) can be moved both manually and by the motor (20). The motor (20) is connected to at least two suspension members (12) by a fixed gear, and the motor (20) is an electric motor with a detent torque of 0 - 1000 mNm, preferably 10 - 500 mNm, most preferably 20 - 250 mNm. The invention also relates to a method in connection with a sash (10) of a fume cupboard (2).

Description

[0001] The invention relates to a system in connection with a sash of a fume cupboard, the system including a sash adapted to be vertically movable, which sash is supported by two or more suspension elements passing through pulleys on one or more counterweights, and the system comprising a motor, which motor is connected to at least two suspension elements via a shaft, and which sash can be moved both manually and by the motor. The invention also relates to a corresponding method.

[0002] As state of the art, patent publication CN101481982A is known, which shows a sash where a single motor is connected via a pulley and a shaft to two suspension cables of the sash, whereby the sash is made to move smoothly up and down by the force of the motor. The publication mentions that in order to enable manual operation of the sash, a clutch must be used to disengage the motor from the suspension cables. This eliminates the resistance caused by the motor and allows the sash to be moved up and down manually with less force. The problem with this solution is its complexity. If the sash is to be operated by both motor and manual power, a clutch must be used, making the fume cupboard complex and costly.

[0003] If the clutch is not used in the solution according to publication CN101481982A and the sash is moved manually, a considerable force is required to move the sash, because at the same time the motor must also be rotated manually. According to the clause 7.3.4. of the current European standard for fume cupboards SFS-EN 14175-2:2003, in force since 2003, the force required to move an individual sash shall not exceed 30 N or, in the case of a set of sashes, 50 N when tested according to clause 6.2 of the standard EN 14175-3:2003. In state of the art fume cupboards with a motorized sash, a clutch, for example a magnetic clutch, must be used so that the sash can also be operated manually with a sufficiently low force.

[0004] In addition, clause 7.3.4 of the European standard SFS-EN 14175-2:2003 specifies that it must be possible to manually override the automatic movement of the sash of an electrically operated fume cupboard. A sensor should be provided in the fume cupboard to stop the movement if there is an obstacle in the way of the sash. The speed of the automatic sash shall not exceed 0.5 m / s.

[0005] It is an object of the invention to provide a system and method in connection with a sash of a fume cupboard, which allow the up and down movement of the sash, both by a motor and manually, to be carried out more simply and easily than before. The characteristic features of the system according to the invention are set out in the attached claim 1 and the characteristic features of the method in the attached claim 13.

[0006] The system according to the invention in connection with a sash of a fume cupboard includes a sash adapted to be vertically movable, which sash is supported by two or more suspension elements passing through pulleys on one or more counterweights, and which system comprises a motor, which motor is connected to at least two suspension elements via a shaft, and which sash can be moved both manually and by the motor. The motor is connected to at least two suspension elements via a fixed gear, and the motor is an electric motor with a detent torque of 0 - 1000 mNm, preferably 10 - 500 mNm, most preferably 20 - 250 mNm.

[0007] In other words, the fixed gear here means that the connection between the motor and the suspension element does not comprise a clutch or a gearbox. Here detent torque, which is also known as cogging torque or gearing torque or no-current torque, refers to the torque required to rotate the motor shaft when no current is applied to the motor. In other words, the motor is optimally selected so that, in addition to the optimal torque, speed and volume of sound, the free-wheeling resistance of the motor is low enough to move the sash manually without requiring too much force from the user. The ability to move the sash easily by hand with little force is a feature related to the safe use of the fume cupboard, as it must be possible to open and close the sash quickly if necessary. In other words, in the system according to the invention, the sash is adapted to be moved by means of a motor, which is selected in a surprising way that deviates from the state of the art, so that the motor can be integrally connected to the suspension elements in such a way that the force required to move the sash manually does not exceed the definition according to the above-mentioned standard, even if the motor is kept continuously connected to the sash and the motor is rotated when moving the sash manually. Connecting the motor to at least two suspension elements via a shaft is essential in order to make the sash move smoothly so that the sash does not go askew, in which case the sash would catch on the edges of the space provided. The shaft also enables the use of only one motor. In this way, the system in connection with a sash of a fume cupboard can be made simpler and more cost-effective than before.

[0008] In one embodiment, the motor shaft is directly connected to one pulley. In this way, the system can be made as simple as possible by transmitting the motor power directly to the pulley through which the suspension element of the sash passes.

[0009] In one embodiment, the motor is connected to one pulley by a belt. In this way, the gear ratio of the motor can be changed. In other words, the motor can be connected to the pulley that moves the sash with a 1:1 gear ratio, either with or without a belt, but when using a belt to transmit the power, the gear can be changed, i.e. the vertical speed of movement of the sash can be made to differ from the speed of rotation of the motor shaft. However, changing the gear is a measure related to the design and manufacture of the fume cupboard and the gear is not changed during use of the fume cupboard.

[0010] Here, a belt is a general term for a motor power transmission means that can be connected, for example, between the motor shaft and the pulley. A belt can be, for example, a toothed belt or a chain.

[0011] In one embodiment, the motor is connected directly to the shaft. In this way, the system can alternatively be implemented as simply as possible.

[0012] In one embodiment, the motor is connected directly to the suspension element, which suspension element is preferably a toothed belt. In this way, the system can alternatively be implemented as simply as possible.

[0013] The motor can be a stepper motor, preferably a direct current motor, i.e. a DC motor. In this way, the optimal motor for moving the sash can be selected, and advantageously the speed of the sash, when moved by the motor, can be adjusted. The DC motor also allows better control of the system without the need for separate transformers.

[0014] The axis pull force of the motor is preferably 500 - 5000 mNm, most preferably 1000 - 3000 mNm. In this way, the axis pull force of the motor is suitable for moving the sash of a modern fume cupboard at the required speed of 0 - 0.5 m / s, preferably 0.2 - 0.5 m / s. The mass of the sash is typically 10 - 30 kg.

[0015] The system is counterbalanced, so overcoming the internal friction of the system and working against the mass inertia is essential.

[0016] Preferably, the system comprises a sensor for detecting a user at the front of the fume cupboard. This sensor, i.e. the occupancy sensor, can be used to detect the presence of a user in the vicinity of the fume cupboard, which information can be used to implement the automatic closing of the sash. The sensor can be, for example, an infrared transmitter and / or receiver. Preferably, the system includes software means, the motor is adapted to activate and close the sash with a selected delay when the sensor does not detect a user in the vicinity of the fume cupboard. This allows the sash to close automatically when the user leaves the fume cupboard, making the fume cupboard safer than before.

[0017] More specifically, the system preferably comprises a control unit, i.e. a computer comprising memory means and a processor, and as software means a first program code which is arrangeable on the memory means of the control unit for execution by the processor, and which control unit is adapted by executing the first program code on its processor to activate the motor and close the sash with a selected delay when the sensor does not detect a user in the vicinity of the fume cupboard.

[0018] Preferably, the system comprises a second sensor for detecting an obstacle under the sash. In this way, a sensing means, for example so-called light curtain, can be implemented under the sash, the measured data of which can be used to control the automatic closing and / or opening of the fume cupboard. The sensor can be, for example, an infrared transmitter and / or receiver.

[0019] Preferably, the system comprises software means to adapt the motor to activate and open the sash for a selected distance when the second sensor detects an obstacle under the sash while the sash is stopped. In this way, the user can open the sash for a selected distance without physically touching the fume cupboard, for example by waving a hand or a selected object under the sash in the detection area of the sensor.

[0020] More specifically, the system preferably comprises a control unit, i.e. a computer comprising memory means and a processor, and as software means a second program code which is arrangeable on the memory means of the control unit for execution by the processor, and which control unit is adapted to execute the second program code on its processor to activate the motor and open the sash for a selected distance when the second sensor detects an obstacle under the sash while the sash is stopped.

[0021] Preferably, the system comprises a position sensor for detecting the position of the sash. In this way, the movement of the motor can be stopped quickly and accurately at the selected position of the sash, thus reducing the load on the motor and other structures.

[0022] In one embodiment, the sash is a two-part sash comprising an upper portion and a lower portion, the lower portion being fitted to the shaft connected to the motor by means of a fixed pulley, and the upper portion being fitted to the shaft connected to the motor by means of a bearing-mounted pulley. In this way, the features described above can be implemented in a two-part sash.

[0023] The above-described sensing means for the detection of a user and / or obstacle and the types of embodiments using sensors are independent of the motor characteristics described above. In other words, the sensors according to the invention can be used with any motor and motor connections operating the sash, whereby the motor and suspension element can also be used in conjunction with, for example, a clutch or a gearbox.

[0024] In the method according to the invention in connection with a sash of a fume cupboard, a vertically movable sash is supported by two or more suspension elements passing through pulleys on one or more counterweights, and the method comprises connecting a motor to at least two suspension elements via a shaft so that the sash can be moved both manually and by the motor. The motor is connected to at least two suspension elements via a fixed gear, and the motor is an electric motor with a detent torque of 0 - 1000 mNm, preferably 10 - 500 mNm, preferably 20 - 250 mNm. In this way, the method in connection with a sash of a fume cupboard, where the sash is moved both manually and by the motor, becomes simpler and more cost-effective than before.

[0025] Preferably, the presence of a user at the front of the fume cupboard is detected by a sensor, and when no user is detected, the motor is activated to close the sash after a selected delay. In this way, the fume cupboard becomes safer than before.

[0026] Preferably, the presence of an obstacle under the sash of the fume cupboard is detected with another sensor, and when an obstacle is detected while the sash is stopped, the motor is activated to open the sash for a selected distance. In this way, the user can open the sash for a selected distance by waving a hand or a selected object under the sash in the detection area of the sensor.

[0027] The invention is described in detail below by referring to the accompanying drawings illustrating some embodiments of the invention, wherein Figure 1shows one fume cupboard from the front, Figure 2shows as a schematic diagram a system according to the invention in connection with a sash of a fume cupboard, Figure 3shows as a perspective view a system according to the invention in connection with a sash of a fume cupboard, Figure 4shows as a perspective view another system according to the invention in connection with a sash of a fume cupboard.

[0028] Figure 1 shows one fume cupboard 2 to which the invention can be applied. The fume cupboard 2 includes a working opening 4 at its front, which can be closed and opened by the sash 10. The sash 10 can be stopped at any point between the extremes of its vertical movement. On top of the fume cupboard 2 there are exhaust air ducts 6, through which harmful substances are discharged from the breathing air. The fume cupboard 2 comprises a motor 20 for moving the sash 10 vertically, which motor 20 is presented in more detail in connection with figures 2 - 4. The fume cupboard 2 is further provided here with a control unit 7, which can comprise software means for controlling the motor 20.

[0029] Figure 2 shows a schematic diagram of a system according to the invention in connection with a sash 10 of a fume cupboard 2. Figure 3 shows as a perspective view the structure of the corresponding system, which, however, is not to scale. The system includes a sash 10 adapted to be vertically movable, which is supported here by two suspension elements 12 passing through pulleys 16 on counterweights 14. The system comprises a motor 20, which is connected to suspension elements 12 via a shaft 18. The sash 10 can be moved both manually and by the motor 20. The motor 20 is connected to suspension elements 12 via a fixed gear. The motor 20 is an electric motor with a detent torque of 0 - 1000 mNm, preferably 10 - 500 mNm, most preferably 20 - 250 mNm. Here, the motor 20 is connected to one pulley 16 by a belt 22. In this case, the motor 20 rotates the first pulley 16 via the belt 22, which moves the first suspension element 12. Via the first pulley 16, the motor 20 also rotates the shaft 18 and consequently also the second pulley 16 connected to the shaft 18, which in turn moves the second suspension element 12 as the motor 20 rotates.

[0030] The suspension element 12 can be, for example, a wire, a cord, a chain or a toothed belt. The suspension element 12 rotates around the two pulleys 16, whereby the counterweights 14 hang freely in the rear of the fume cupboard 10. The combined mass of the counterweights 14 is equal to the mass of the sash 10. In this case, the counterweights 14 and the sash 10 are subjected to an equal force of gravity and the system remains in equilibrium. In other words, the sash 10 can be moved vertically, and stopped at any point between the extremes of its vertical movement. Here, the shaft 18 is connected to the pulleys 16 on the side of the sash 10, but the shaft 18 can also be connected to the pulleys 16 on the side of the counterweights 14.

[0031] The motor 20 is therefore constantly mechanically connected to the suspension elements 12. In the case, when the sash 10 is moved manually, the shaft 21 of the motor 20 always rotates. An electric motor always creates resistance when the motor is rotated. However, in the system according to the invention, the electric motor is optimally selected so that the detent torque of the electric motor is sufficiently low so that a sufficiently low force is required to move the sash 10 manually in accordance with the above-mentioned standard. The connection between the motor 20 and the suspension element 12 therefore does not comprise a clutch or a gearbox, but the shaft 21 of the motor 20 rotates whenever the sash 10 is moved vertically. Due to the direct connection of the optimally selected motor 20 and the absence of a gearbox, the resistance caused by the motor 20 is very low during manual operation of the sash 10. However, the power of the motor 20 is chosen to be sufficient to move the sash 10 vertically.

[0032] Here, the motor 20 is a DC stepper motor. The motor 20 can be of the model RB STEP MOTOR 23HD7230-20, for example, with a detent torque of 90 mNm and an axis pull force of ≥1580 mNm. Other electric motors with similar characteristics can also be used as motor 20. The use of a belt 22 is not mandatory, but in an alternative embodiment, for example, the shaft 21 of the motor 20 may be directly connected to one pulley 16. However, the belt 22 can be used to change the gear ratio of the motor 20 so that the gear of the motor 20 is fixed, but other than 1:1, whereby the speed of the motor 20 can be adjusted to match the selected speed of the sash 10, which is also defined in the above-mentioned standard. In each embodiment, the gear ratio is optimally selected to match the speed of the motor 20, the required torque, the appropriate speed of the movement of the sash 10 and the resistance of the motor 20 when operating manually.

[0033] In alternative embodiments, the motor 20 may also, for example, be connected directly to the shaft 18.

[0034] In a further alternative embodiment, the motor 20 may be connected, for example, directly to the suspension element 12, the suspension element 12 being preferably a toothed belt, whereby the shaft 21 of the motor 20 may be securely connected to the suspension element 12 so that the connection between the motor 20 and the suspension element 12 does not slip. One way or another, in the system according to the invention, the power generated by the motor 20 is always transferred to the shaft 18.

[0035] The system herein comprises a sensor 30, i.e. an occupancy sensor, for detecting a user at the front of the fume cupboard 2. The sensor 30 can be any prior art sensor suitable for detecting the presence of a user, such as an infrared transmitter and / or receiver. Here, the sensor 30 is placed in the upper corner of the fume cupboard 2 to detect the presence of the user at the front of the fume cupboard 2. The system further comprises software means adapted to cause the motor 20 to activate and close the sash 10 with a selected delay when the sensor 30 does not detect a user in the vicinity of the fume cupboard 2. The sash 10 is therefore adapted to close, i.e. the motor 20 is adapted to drive the sash 10 to the lower position with an automatically selected delay, if the user leaves the fume cupboard 2, thus improving the safety of the fume cupboard 2 and reducing energy consumption. More specifically, the system preferably comprises a control unit 7, comprising memory means and a processor, and as software means a first program code which is arrangeable on the memory means of the control unit for execution by the processor, and which control unit 7 is adapted by executing the first program code on its processor to activate the motor 20 and close the sash 10 with a selected delay when the sensor 30 does not detect a user in the vicinity of the fume cupboard 2.

[0036] The system comprises control means for activating the motor 20 so that the user can adjust the motor 20 to rotate in a selected direction to move the sash 10 up or down. Control means can comprise, for example, a finger button or a foot pedal according to the prior art.

[0037] Further, the system herein comprises a second sensor 40 for detecting an obstacle under the sash 10. The second sensor 40, i.e. obstacle detecting sensor, can be any state of the art sensor suitable for detecting an object, such as an optical sensor or a so-called light curtain. Here, the second sensor 40 is placed under the pull list of the sash 10 with optical sensors on opposite sides, which are an optical transmitter-receiver pair operating in the infrared range forming a light curtain. In this case, the second sensor 40 is adapted to immediately detect the presence of an obstacle below the pull list, such that the presence of the obstacle cuts off the optical signal between the pair of sensors, whereby the software means is adapted to detect the obstacle. The system further comprises software means adapted to cause the motor 20 to activate and open the sash 10 for a selected distance when the second sensor 40 detects an obstacle under the sash 10 while the sash 10 is stopped. In this case, for example, if the user's hands hit one sensor 40 or the detection area of the other sensor 40, the sash 10 is adapted to move upwards. The sash 10 can also slowly return downwards with a self-selected delay until the second sensor 40 detects an obstacle, at which point it stops. If the obstacle leaves in front of the second sensor 40 and returns, the sash 10 will rise until the obstacle is not detected or for a predetermined distance. In this way, the user can control the motor 20 without physically contacting the control means. With the second sensor 40, the automatic stopping condition of the sash 10 defined in the above-mentioned standard can also be implemented. More specifically, the system preferably comprises a control unit 7, comprising memory means and a processor, and as software means a second program code which is arrangeable on the memory means of the control unit 7 for execution by the processor, and which control unit 7 is adapted by executing the second program code on its processor to activate the motor 20 and open the sash 10 for a selected distance when the second sensor 40 detects an obstacle under the sash 10 while the sash 10 is stopped.

[0038] In other words, the second sensor 40 under the pull list of the sash 10 can be used to move the sash 10 upwards: If the sash 10 is in the lower position when the second sensor 40 detects an obstacle (for example the user's finger), the sash 10 rises for a predetermined distance, for example 30 cm. If the sash 10 is stopped at any other height when the second sensor 40 detects an obstacle, the sash 10 rises for a predetermined distance, for example 5 cm. This can happen several times in a row, causing the sash 10 to rise even more.

[0039] This allows the user to intuitively operate the sash 10 of the fume cupboard 2 using his / her hands, but without touching the sash 10 or the physical control means. The benefits are improved usability and reduced contamination risk, as there is no need to physically touch the sash 10 or other control devices, as well as higher operational safety when the hands are free to do other things.

[0040] The above-described sensing means and related software tools and method steps can be used with the system according to the invention and independently of it. In other words, the software tools and method steps described herein are independent on the motor 20 being connected.

[0041] In addition, this system comprises a position sensor for detecting the position of the sash 10. The position sensor may be any state of the art position sensor suitable for detecting the position of the sash 10, such as a potentiometer. With the position sensor, which directly detects the position of the sash 10 in different positions, it is possible to prevent the motor 20 from being loaded in the extreme position, and to stop the sash 10 precisely at different heights.

[0042] The load of the motor 20 can be monitored as a function of lifting movements and thus verify and statistically predict the need for system maintenance / lubrication, as the resistance of the motor 20 increases over time.

[0043] Figure 4 shows as a perspective view another system according to the invention in connection with a sash of a fume cupboard, the system comprising the suspension of the two-part sash 10. Here, the sash 10 is therefore a two-part sash, comprising an upper part and a lower part. The lower part is fitted to the shaft 18 connected to the motor 20 by a fixed pulley 16 as described above. Instead, the upper part of the sash 10 is suspended by a suspension element 13, which is fitted to a shaft 18 connected to the motor 20 by means of a bearing-mounted pulley 17. In other words, due to the bearing, the rotation of the shaft 18 does not rotate the pulley 17 and thus does not move the suspension element 13. This allows vertical movement of the upper and lower parts of the sash 10 as in the prior art non-motorized fume cupboard 2, and the two-part sash 10 to be adapted to close automatically as described above. When closing, the lower part of the sash pulls the upper part along with it, and when opening, the lower part pushes the upper part along with it, which is known from state of the art non-motorized fume cupboards. Alternatively, the pulley 17 at the top of the sash 10 can be separate from the shaft 18. In this case, the structure takes up more space, but works on the same principle.

Claims

1. A system in connection with a sash (10) of a fume cupboard (2), the system including a sash (10) adapted to be vertically movable, which sash (10) is supported by two or more suspension elements (12) passing through pulleys (16) on one or more counterweights (14), and the system comprising a motor (20), which motor (20) is connected to at least two suspension elements (12) via a shaft (18), and which sash (10) is movable both manually and by the motor (20), characterized in that said motor (20) is connected to said at least two suspension elements (12) by a fixed gear, and said motor (20) is an electric motor with a detent torque of 0 - 1000 mNm, preferably 10 - 500 mNm, most preferably 20 - 250 mNm.

2. The system according to Claim 1, characterized in that the shaft (21) of said motor (20) is directly connected to one of said pulleys (16).

3. The system according to Claim 1, characterized in that said motor (20) is connected to one of said pulleys (16) by a belt (22).

4. The system according to Claim 1, characterized in that said motor (20) is directly connected to said shaft (18).

5. The system according to Claim 1, characterized in that said motor (20) is directly connected to a suspension element (12), which suspension element (12) is preferably a toothed belt.

6. The system according to any of Claims 1 - 5, characterized in that said motor (20) is a stepper motor, preferably a direct current motor.

7. The system according to any of Claims 1 - 6, characterized in that the system comprises a sensor (30) for detecting a user at the front of the fume cupboard.

8. The system according to Claim 7, characterized in that the system comprises software means for adapting said motor (20) to activate and close the sash (10) with a selected delay when said sensor (30) does not detect a user in the vicinity of the fume cupboard (2).

9. The system according to any of Claims 1 - 8, characterized in that the system comprises a second sensor (40) for detecting an obstacle under the sash (10).

10. The system according to Claim 9, characterized in that the system comprises software means for adapting said motor (20) to activate and open the sash (10) for a selected distance when said second sensor (40) detects an obstacle under the sash (10) while the sash (10) is stopped.

11. The system according to any of claims 1 - 10, characterized in that the system comprises a position sensor for detecting the position of the sash (10).

12. The system according to any of Claims 1 - 11, characterized in that said sash (10) is a two-part sash, which sash (10) comprises an upper part and a lower part, which lower part is fitted to the shaft (18) connected to said motor (20) by a fixed pulley (16), and which upper part is fitted to the shaft (18) connected to said motor (20) by a bearing-mounted pulley (17).

13. A method in connection with a sash (10) of a fume cupboard (2), in which method a vertically movable sash (10) is supported by two or more suspension elements (12) passing through pulleys (16) on one or more counterweights (14), and in which method a motor (20) is connected to at least two suspension elements (12) via a shaft (18) so that the sash (10) is movable both manually and by the motor (20), characterized in that said motor (20) is connected to said at least two suspension elements (12) by a fixed gear, and said motor (20) is an electric motor with a detent torque of 0 - 1000 mNm, preferably 10 - 500 mNm, most preferably 20 - 250 mNm.

14. The method according to Claim 13, characterized in that the presence of a user at the front of the fume cupboard (2) is detected by a sensor (30), and when no user is detected, said motor (20) is activated to close the sash (10) after a selected delay.

15. The method according to Claim 13 or 14, characterized in that the presence of an obstacle under the sash (10) of the fume cupboard (2) is detected by a second sensor (40), and when the obstacle is detected while the sash (10) is stopped, said motor (20) is activated to open the sash (10) for a selected distance.

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