NL2024256B1 - Sensor unit and sensing method for a valve system - Google Patents
Sensor unit and sensing method for a valve system Download PDFInfo
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- NL2024256B1 NL2024256B1 NL2024256A NL2024256A NL2024256B1 NL 2024256 B1 NL2024256 B1 NL 2024256B1 NL 2024256 A NL2024256 A NL 2024256A NL 2024256 A NL2024256 A NL 2024256A NL 2024256 B1 NL2024256 B1 NL 2024256B1
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- magnetic field
- permanent magnet
- valve
- valve system
- sensor unit
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
- F16K37/00—Special means in or on valves or other cut-off apparatus for indicating or recording operation thereof, or for enabling an alarm to be given
- F16K37/0025—Electrical or magnetic means
- F16K37/0033—Electrical or magnetic means using a permanent magnet, e.g. in combination with a reed relays
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- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Indication Of The Valve Opening Or Closing Status (AREA)
Abstract
Title: Sensor unit and sensing method for a valve system Abstract There is disclosed a sensor unit for detecting the closed position of an industrial valve, the sensor unit comprising at least a first permanent magnet, a second permanent magnet and a magnetic field sensor element. The sensor element is configured detecting variations in the superposed magnetic fields of the magnets, Which variations indicate that the valve is not in closed position anymore. [Fig. 2a]
Description
P123719NL00 Title: Sensor unit and sensing method for a valve system The invention relates to a sensor unit for sensing a position of a valve system.
Industrial valve systems, such as multi-turn valve systems or linear motion valve systems, are often used on industrial plants. Such valve systems are often positioned in dangerous, hazardous, explosion sensitive or high risk areas, or in areas that are difficult to access. These valve systems typically comprise a housing that is positioned in or to a piping. In the valve system housing a valve system stem, with at its end a valve body, is movable arranged. The valve body is adjustable between an open position in which it allows flow through the piping, and a closed position in which it blocks flow through the piping. The valve system stem can be linearly or rotating movable with respect to the valve system housing. The valve system stem extends outside of the valve system housing, usually through a yoke mounted on the valve system housing. The valve system stem is typically operated manually with an operating element, e.g. a hand wheel mounted to the stem. Depending on the type of valve system, an up or downward movement provides for opening and/or closing of the valve body, or a rotating movement provides for opening or closing of the valve body, allowing fluid to pass through the piping or not.
On industrial sites comprising often kilometers of piping, a multitude of these industrial valve systems are positioned on site. In view of the multitude of valve systems, inspection of the valve systems is an almost ongoing effort. Further, for a reliable and safe operation of the industrial site, it 1s important that valve systems that are to be in a closed position, effectively also are in the closed position. Any leakage or spillage of fluid flow due to the fact that a valve system is not entirely in the closed position, can be an economic loss, in particular given the multitude of industrial valve systems on the plant site. Any leakage or spillage can be hazardous, in particular when inflammable fluids are involved. To that end, inspection of the valve systems to check whether they are indeed in the closed position is relied upon. Such inspection is often done visually, i.e. it is checked whether the stem of the valve system is in its lowest position. However, even with such a visual inspection, it might happen that valve systems may not be entirely closed, and thus may leak.
This may not only have an economic effect, due to loss of valuable fluids, but may also imply a safety risk as some of these fluids may be inflammable.
Therefor, it is important that valve systems that are supposed to be in closed position are indeed in their closed position. Thereto, it 1s known to integrate a sensor in the valve system, which sensor comprises a magnet mounted on the stem and a magnetic sensor e.g. mounted to the yoke of the valve system. The magnetic sensor then senses the change in magnetic flux due to the movement of the stem, and thus of the magnet. However, such a configuration is relatively vulnerable to external disturbances. Also, such a sensor mainly senses the change in position of the valve system, but is not very accurate in detecting whether the valve system 1s closed. Additionally, such a sensor is usually rather bulky and integrated to the valve system at its manufacturing, retro-fitting is often not possible or rather expensive. So, even for valve systems having such a sensor, there may still be relied onto human, visual inspection of the closed position of the valve system.
Therefor, there is a need for an accurate determination of the closed position of such industrial valve systems.
To that end, the invention provides for a sensor unit for detecting a closed position of an industrial valve system, the sensor unit comprising a first permanent magnet arranged to be mounted onto a movable stem of the valve system, a second permanent magnet arranged to mounted onto a stationary part of the valve system, and a magnetic field sensor element arranged to mounted to stationary part of the valve system, wherein the magnetic field sensor element is configured to detect the magnetic fields of both permanent magnets.
By providing two permanent magnets, mounted in proximity to each other, and a magnetic field sensor element mounted in proximity to the magnets, the set-up 1s much less vulnerable to external interference. The configuration of two permanent magnets and a magnetic field sensor element mounted in proximity, the magnetic field sensor is much less sensitive to external interferences and is to sense mainly the magnetic field lines of the two permanent magnets. Also, such permanent magnets may have relatively strong magnetic field lines making the detection by the magnetic field sensor element less sensitive to interference or disturbance by external factors. Thus, a more reliable and robust detection of the magnetic field lines can be obtained.
Furthermore, by configuring the magnetic field sensor element such that it can detect variations in the magnetic interference lines of the permanent magnets, a relatively accurate position determination can be obtained. By providing two permanent magnets a more accurate position determination can be done than with a single magnet, as with a single magnet a defined reference position often lacks. Then, variations can be detected, but absolute position almost not. By providing two magnets a discrete reference position can be defined, e.g. by a certain distance between the permanent magnets. By defining this discrete reference position as corresponding to the closed position of the valve body, the magnetic field sensor element then may detect any deviation from this discrete reference position and then can signal that the valve body 1s not in closed position anymore.
When at least two permanent magnets are used, the magnetic field lines of the magnets are interfering with each other. The magnetic field lines sum up with each other and may create a zone with no field, with very strong field or very directed field. The magnetic field sensor element can then be configured to detect e.g. the ‘no-field’ area which corresponds with a discrete position of the magnets with respect to each other. The magnetic field sensor element can e.g. be any type of a magnetometer, such as a Hall sensor or a fluxgate sensor.
Arranging the magnets and the magnetic field sensor element such that the sensor element detects ‘no field or ‘very strong’ field or ‘very directed’ field, can be done by varying the position of one of the magnets and of the magnetic field sensor element with respect to the fixedly mounted magnet, being the first permanent magnet. This is done during calibration.
During calibration, the valve body of the industrial valve system is in closed position. The position of the first permanent magnet, mounted on the stem, corresponds with the closed position of the valve body. The position of the second permanent magnet and/or the magnetic field sensor element can then be adjusted until the magnetic field sensor element detects the discrete position of interference of the magnetic field lines of the magnets, typically a zero-field. Then, the closed position is defined as a discrete reference, and any deviation therefrom can then be recognized as that the valve system is not in closed position anymore. Alternatively, calibration can be done by moving the second permanent magnet and/or the magnetic field sensor element to a position where the maximum (‘very strong’ or ‘very directed’) or minimum (‘zero field’) interference of the magnetic field lines. This step may be done with the valve body in any position. Thereafter, the valve body is adjusted to the closed position. During the adjustment of the valve body from the previous position to the closed position, ripples of the magnetic field can be counted, and, as such, the calibration position, namely the closed position of the valve body, can be accurately defined. With this method, the calibration position can be relatively easy adjusted, e.g. when due to wear or ageing or any other influence, the closed position of the valve changes somewhat. Then, it is only sufficient to re-count the ripples encountered between the previous selected interference position, and the closed position to define the calibration position. This can be done both for linearly movable valve stems as well as for rotatable moving valve stems. Both for the linearly movable valve stem and for the rotatable moving valve stem, the distance between both permanent magnets changes, and ripples of 5 the magnetic field can be counted.
The permanent magnets can have any shape, such as circular or rectangular or star-shaped etc. The shape of the magnet is reflected in the magnetic field lines resulting from that particular magnet, which can be advantageous in defining the calibration position.
Advantageously, the second permanent magnet and the magnetic field sensor element are both enclosed in a housing. The housing may then be connected to a stationary part of the valve system, such as a yoke of the valve system or to a rotating part of the valve system, such as a hand wheel of a valve system. The first permanent magnet can be fixedly connected to the valve stem. By providing such a housing, retrofitting of existing industrial valve system with the sensor unit can be done relatively easy. Advantageously, the housing is connected to the valve system by means of a bracket. The bracket is then fixedly connected to the valve system and the housing can then be adjustable connectable to the bracket. Thus, the position of the housing can easily be adjusted during the calibration to find the minimum or maximum interference area where the properties of the magnetic field lines sum up to a zero value or to a maximum value or a maximum direction of the magnetic field. The bracket can e.g. be connected to a stationary part of the valve system, such that the position of the first permanent magnet with respect to the housing and bracket can change, when the valve stem adjusts. Alternatively, the bracket can e.g. be mounted to a hand wheel, of which a horizontal position remains stationary while the valve stem moves up or down with respect to the hand wheel. Although the bracket in that case rotates together with the hand wheel when turning the hand wheel, this does not affect the functioning of the sensor unit.
Further, by providing a housing, the components inside of the housing can be protected from environmental influences, such as water, sun or dirt. Also, the housing may protect the components from being tampered with or from being accidentally damaged. Furthermore, inside of the housing a printed circuit board can be provided to which the magnetic field sensor element can be connected. To the printed circuit board, further an energy supply can be connected, preferably an energy supply comprising an energy storage element. By providing an energy storage element that is configured for powering the magnetic field sensor element, a self-contained and self-supplying sensor unit can be provided, that can be a stand-alone unit on the valve system. As such, the sensor unit can be independent of any external energy supply. Typically, the energy storage element can be a battery. Alternatively, instead of a battery, a capacitor can be provided, or a photovoltaic element that is providing energy to a storage element, etc.
Many variants are possible. Typically, inspection intervals for such industrial valve systems are about three years. For example, the battery can be provided for a lifetime of three to five years, such that the battery may last until the next inspection interval.
The sensor unit, preferably the printed circuit board, may further be provided with a wireless communications unit. The wireless communications unit can provide for wireless communication with a remote control unit or with a remote server. In particular, the wireless communications unit is configured for transmitting an alert signal to a remote server or a remote control unit when a deviation from the closed position is detected.
Advantageously, the sensor unit, preferably the printed circuit board arranged in the housing, is provided with a controller. The controller can be configured to prompt the magnetic field sensor element to do a detection run of the position of the valve body. The magnetic field sensor element can then detect whether the position of the valve body still corresponds with the calibration position. When there is a deviation detected, the sensor element may provide an alert signal to the wireless communications unit that can transmit it to a remote server or control unit.
By providing such a sensor unit, an industrial valve system can be relatively easy retrofitted with a sensor for detecting the closed position. Contrary to conventional valve sensor, the sensor unit according to the invention only detects the closed position of the valve body in an accurate and reliable manner. It is not of interest to known where other positions of the valve body, but the only interest is to accurately determine the closed position of the valve body of the valve system and to detect any deviation therefrom.
Another aspect of the disclosure is to provide for a method for retrofitting an industrial valve system with a sensor unit, the method comprising: providing a sensor unit; mounting the housing with the magnetic field sensor element and the second permanent magnet to a stationary part of the industrial valve system; mounting the first permanent magnet to the stem of the valve system; calibrating the sensor unit.
In another aspect of the disclosure there is provided for an industrial valve system comprising a stationary valve part for mounting to a pipe section; a valve stem movable arranged in the stationary valve part, wherein the valve stem is movable between a closed position in which a valve body mounted to the valve stem closes flow passage through the pipe section, and an open position in which the valve element allows flow passage through the pipe section, further comprising a sensor unit.
Further advantageous embodiments are represented in the subclaims.
These and other aspects will be further elucidated with reference to the drawing comprising figures of exemplary embodiments. Corresponding elements are designated with corresponding reference signs. In the drawing shows:
Fig. 1 a schematic cross-section of an industrial valve system; Fig. 2a a schematic cross-section of an industrial valve system with a sensor unit; Fig. 2b a schematic cross-section of an industrial valve system with a sensor unit; Fig. 3 a schematic view of magnetic field lines of two permanent magnets; Fig. 4a a schematic diagram of the magnetic field angle at the sensor element during movement of the first permanent magnet; Fig. 4b a schematic diagram of the magnetic field intensity at the sensor element during movement of the first permanent magnet.
Fig. 5 a schematic representation of an embodiment of the sensor unit.
It is to be noted that the figures are given by way of exemplary examples and are not limiting to the disclosure. The drawings may not be to scale.
Fig. 1 shows a cross-section of an industrial valve system 1. The industrial valve system 1 is here positioned in between an upstream pipe section 2 and a downstream pipe section 3. The valve system 1 comprises a stationary valve part 4 here comprising a housing 5 and a yoke 6. In the stationary valve part 4, a valve stem 7 is movable arranged. The valve stem 7 is at a lower end thereof provided with a valve body 8. The valve body 8 is, together with the valve stem 7, adjustable between a closed position, in which the fluid flow passage through the pipe section is blocked, as shown in fig. la, and an open position in which the fluid flow through the pipe section is allowed, as shown in fig. 1b. In this embodiment of an industrial valve system, a hand wheel 9 is provided that can move the valve stem 7, and thus the valve body 8, up and down. By rotating the hand wheel 9, the valve stem 7 configured as a spindle, moves up or down, and consequently the valve body 8 moves up or down. For these industrial valve systems 1 it is important to accurately determine the closed position of the valve body 8. Thereto, the industrial valve 1 is provided with a sensor unit 10 comprising a first permanent magnet 11 mounted onto the movable valve stem 7, and a second permanent magnet 12 mounted to the stationary part 4 of the valve
1. Further, the sensor unit 10 comprises a magnetic field sensor element 13 that is mounted to the stationary part 4 of the valve 1. The magnetic field sensor element 13 is configured to detect the magnetic field lines of both permanent magnets.
The magnets 11, 12 used are permanent magnets that are mounted in proximity to each other. As such, disturbance of the their magnetic field by external sources can be relatively limited and the magnetic field sensor can detect the magnetic field lines relatively reliable with no or limited influence from external interferences. So, with a rather limited number of components an existing industrial valve 1 can be retrofitted with a sensor unit 10 for detecting the closed position of the valve body 8.
Both permanent magnets have magnetic field lines and these magnetic field lines sum up, at a certain position there can be a zero magnetic field, at another position there can be a maximum magnetic field, or a maximum directed magnetic field. These positions are discrete, and advantageously, such a position is obtained when the valve body 8 is in the closed position. Then, the magnetic field sensor element 13 can simply detect the zero or maximum or maximum directed field. To obtain this position when the valve body 8 is in closed position, the position of one of the permanent magnets and/or of the magnetic field sensor element is adaptable until this specific discrete spot can be detected. For example, the second permanent magnet 12 and the magnetic field sensor element can be adapted until the specific position is obtained. Then, it is defined that the closed position of the valve body 8 is when the magnetic field sensor element detects the specific spot of zero field or maximum field or maximum field direction.
In the embodiment of figure 2a and figure 2b, the magnetic field sensor element 13 and the second permanent magnet 12 are mounted in or to a housing 15. Here, the magnetic field sensor element 13 is mounted in the housing 15 and the second permanent magnet 12 is mounted on the housing 15, alternatively, the second permanent magnet 12 may be arranged in the housing 15. The housing 15 is mounted with brackets to the hand wheel 9 of the industrial valve system 1. By providing the second permanent magnet 12 and the magnetic field sensor element 13 to the same housing 15, it can be obtained that the magnetic field sensor element 13 is positioned in proximity to the second permanent magnet 12. The housing 15 is preferably adjustable with respect to the brackets. The brackets may for example have arms over which the housing can be slidingly adjusted. Once the housing 15 is in the determined position, its position can be fixed with respect to the bracket, e.g. by tightening bolts.
The first permanent magnet 11 is mounted on top of the stem 7, as this is a relatively easy accessible position and the first permanent magnet 11 may not hinder the operation of the valve stem 7. By turning the hand wheel 9, the stem 7 moves up and down, and the distance D between the first permanent magnet 11 and the second permanent magnet 12 changes, as seen in the schematic views of fig. 2a and fig. 2b. When looking to the positioning of the magnets in a top view, there may be a distance between them as well, the magnets need not to be positioned in line. However, the distance between the magnets in a top view does not change when the valve stem moves in a linear fashion. Here, a valve system with a linearly movable valve stem 1s shown to which the sensor unit is mounted, but the sensor unit can equally be used for rotatable movable valve stems, e.g. of a rotating valve body. For a rotatable movable valve stem, the first permanent magnet 11 may be mounted to the valve stem as well, preferably to a side of the valve stem, such that any rotational movement of the valve stem affects the distance between the first permanent magnet 11 and the second permanent magnet 12 mounted to the stationary part 4 of the valve system
1. Rotational movement of the valve stem may be the result of the valve body not being in closed position anymore, which results in a change in the interference of the magnetic field lines of the first and the second permanent magnets 11, 12, sensed by the magnetic field sensor element 13. By positioning the first permanent magnet 11, the second permanent magnet 12 and the magnetic field sensor element 13 all on the same industrial valve system 1, they are positioned in sufficiently close proximity to each other. Thus, the magnetic field sensor element 13 can accurately sense the magnetic field lines of the magnets 11, 12 with minimum or no interference or disturbance by external or environmental sources. This provides for a reliable detection and/or reliable functioning of the magnetic field sensor element 13.
The second permanent magnet 12 acts as a reference source and provides for a strong reference magnetic field in any situation, irrespective of any environmental or external influences. The first permanent magnet 11, fixed to the valve stem 7, acts as a field canceller or field reverser, as is illustrated in fig. 3 and figs. 4a and 4b.
Figure 3 shows a schematic representation of the magnetic field lines of the permanent magnets 11, 12 positioned at a distance D from each other. Permanent magnet 12 is the reference magnet and insures a constant strength field in the sensor element 13. Upon movement of the valve stem 7, the magnet 11 moves up along the direction of the arrow A, and the distance D changes. When the magnet 11 approaches the magnet 12, the magnetic field in the sensor element 13 changes and the sensor element 13 detects a smaller magnetic field. At a certain distance between the magnet 11 and the magnet 12, a ‘zero-field spot 16 is sensed by the sensor element 13, being the spot where the two magnetic fields cancel each other. This is a destructive interference point causing a sudden drop in the field strength |B] sensed by the sensor element 13. This is illustrated in figure 4b.
Tracking this sudden drop in the field strength gives the exact position of the first permanent magnet 11, and thus of the valve stem 7 and the valve body 8 to which the first permanent magnet 11 is fixed. During calibration, use is made of this sudden drop to position the magnetic field sensor element 13 such that it senses this spot 16 when the first permanent magnet 11, and thus the valve body 8 to which it is connected, in the closed position of the valve body 8. During calibration, the position of the second permanent magnet 12 and the sensor element 13 is adjusted until the sensor element 13 senses the spot 16. Then the position of the second permanent magnet 12 and the sensor element 13 is fixated. During use, when the sensor element 13 senses a deviation in the magnetic field strength, it is detected that the position of the permanent magnet 11 has changed, and, consequently that the valve body 8 is not in closed position anymore. The ‘zero-field’ spot 16 only occurs in such a defined configuration of the permanent magnets, which makes the sensor unit resilient for false triggers and/or rather insensitive for environmental or external influences. Additionally, as shown in figure 4a, it can be seen that, just after the spot 16 is reached, the angle of the magnetic field suddenly changes as well. So, the absolute position of the valve body can be checked, namely whether the valve body is in closed position or not. Figure 5 shows a schematic representation of the sensor unit 10 comprising the first permanent magnet 11, the second permanent magnet 12 and the sensor element 13. The second permanent magnet 12 and the sensor element 13 are arranged in or to the housing 15. Further, there is provided for a controller 17, a power supply 18 and a communications unit
19. The power supply 18 preferably comprises an energy storage element such as a battery or a capacitor. The communications unit 19 is preferably a wireless communications unit. Further, there is provided a user interface
20. The controller 17 advantageously is configured to receive a sensor signal from the sensor element 13. The controller 17 can further be configured to compare the sensor signal with the calibration signal, and if a deviation is detected, the controller 17 may output an alert signal to the user interface 20 and/or the communications unit 19. The user interface 20 may for example comprise an auditive or visual signaling element that provides an alert signal when instructed thereto by the controller 17. The communications unit 19 preferably is a wireless communications unit that can transmit a wireless signal to a remote control unit and/or a remote server. The user interface 20 advantageously also is configured to receive a user input, in particular during the calibration process. The user may for example input that the calibration process is completed and that the housing 15 1s the defined position. The calibration value can be stored in the controller 17, where it can be used to compare with later sensed values by the sensor element 13. The controller 17 may further be configured to periodically request the sensor element 13 to perform a run and to check on the magnetic field strength. In between these runs, the sensor element 13 may be allowed to go in sleep mode. This saves energy and power consumption. The power supply 18, preferably comprising an energy storage element, may be sufficient to perform a predefined number of sensor element runs. Preferably, the energy stored in the energy storage element is sufficient to guarantee the running of the sensor element 13 in the period between two major inspection rounds, typically such period is about 3 to 5 years. Advantageously, the housing 15 comprises a printed circuit board to which the controller 17 and the power supply 18 are connected. Preferably, the communications unit 19 and/or the user interface 20 are connected to the printed circuit board as well.
The valve body is adjustable between a closed position and an open position. The closed position is also referred to as the fully closed position or the entirely closed position. The open position is considered to be the fully open position. Any other position of the valve body that is not the closed position, and is not the fully open position, is denoted as a partially open position. A partially open position is therefore between the closed position and the open position. The closed position is considered a discrete position. So, when the sensor element 13 detects that the position of the first permanent magnet 11 is changed, the position of the valve body 8, to which the first permanent magnet is fixed, is not the closed position anymore.
There is disclosed a sensor unit for detecting the closed position of an industrial valve, the sensor unit comprising at least a first permanent magnet, a second permanent magnet and a magnetic field sensor element. The sensor element is configured detecting variations in the superposed magnetic fields of the magnets, which variations indicate that the valve is not in closed position anymore.
For the purpose of clarity and a concise description, features are described herein as part of the same or separate embodiments, however, it will be appreciated that the scope of the claims and disclosure may include embodiments having combinations of all or some of the features described. It may be understood that the embodiments shown have the same or similar components, apart from where they are described as being different.
In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word ‘comprising’ does not exclude the presence of other features or steps than those listed in a claim. Furthermore, the words ‘a’ and ‘an’ shall not be construed as limited to ‘only one’, but instead are used to mean ‘at least one’, and do not exclude a plurality. The mere fact that certain measures are recited in mutually different claims does not indicate that a combination of these measures cannot be used to an advantage. Many variants will be apparent to the person skilled in the art. All variants are understood to be comprised within the scope defined in the following claims.
Claims (11)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL2024256A NL2024256B1 (en) | 2019-11-18 | 2019-11-18 | Sensor unit and sensing method for a valve system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL2024256A NL2024256B1 (en) | 2019-11-18 | 2019-11-18 | Sensor unit and sensing method for a valve system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| NL2024256B1 true NL2024256B1 (en) | 2021-07-29 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| NL2024256A NL2024256B1 (en) | 2019-11-18 | 2019-11-18 | Sensor unit and sensing method for a valve system |
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| Country | Link |
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| NL (1) | NL2024256B1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20220282683A1 (en) * | 2021-03-03 | 2022-09-08 | Vieletech Inc | Apparatus and method for engine control |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3333497A1 (en) * | 1983-09-16 | 1985-04-18 | Vdo Adolf Schindling Ag, 6000 Frankfurt | Position transmitter having at least one Hall switching element |
| DE4221625C1 (en) * | 1991-08-09 | 1993-04-01 | Leopold Kostal Gmbh & Co Kg, 5880 Luedenscheid, De | Electrical switch suitable for motor vehicle e.g. throttle flap or steering column - has Hall component and ferromagnetic shield assigned to housing base and cover |
| US6114823A (en) * | 1997-12-30 | 2000-09-05 | Agf Manufacturing, Inc. | Circuit and apparatus for sensing fluid flow |
| US6752171B1 (en) * | 1999-08-20 | 2004-06-22 | Samson Aktiengesellschaft | Control-valve drive with sensor unit for detecting the position of the valve |
| US7025089B1 (en) * | 2004-03-03 | 2006-04-11 | Ian Marsac | System for accurately measuring choke position |
| DE102008062301A1 (en) * | 2007-12-20 | 2009-06-25 | Robert Buck | Inclined seat-standard backflow preventer for use in e.g. central water supply plant, has guide pin extending from valve seat in valve opening direction and entering into receiving guide or guide sleeve, which is component of valve cover |
-
2019
- 2019-11-18 NL NL2024256A patent/NL2024256B1/en not_active IP Right Cessation
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3333497A1 (en) * | 1983-09-16 | 1985-04-18 | Vdo Adolf Schindling Ag, 6000 Frankfurt | Position transmitter having at least one Hall switching element |
| DE4221625C1 (en) * | 1991-08-09 | 1993-04-01 | Leopold Kostal Gmbh & Co Kg, 5880 Luedenscheid, De | Electrical switch suitable for motor vehicle e.g. throttle flap or steering column - has Hall component and ferromagnetic shield assigned to housing base and cover |
| US6114823A (en) * | 1997-12-30 | 2000-09-05 | Agf Manufacturing, Inc. | Circuit and apparatus for sensing fluid flow |
| US6752171B1 (en) * | 1999-08-20 | 2004-06-22 | Samson Aktiengesellschaft | Control-valve drive with sensor unit for detecting the position of the valve |
| US7025089B1 (en) * | 2004-03-03 | 2006-04-11 | Ian Marsac | System for accurately measuring choke position |
| DE102008062301A1 (en) * | 2007-12-20 | 2009-06-25 | Robert Buck | Inclined seat-standard backflow preventer for use in e.g. central water supply plant, has guide pin extending from valve seat in valve opening direction and entering into receiving guide or guide sleeve, which is component of valve cover |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20220282683A1 (en) * | 2021-03-03 | 2022-09-08 | Vieletech Inc | Apparatus and method for engine control |
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| MM | Lapsed because of non-payment of the annual fee |
Effective date: 20221201 |