EP1436573A1 - Surface switch for determining the surface level - Google Patents
Surface switch for determining the surface levelInfo
- Publication number
- EP1436573A1 EP1436573A1 EP02758500A EP02758500A EP1436573A1 EP 1436573 A1 EP1436573 A1 EP 1436573A1 EP 02758500 A EP02758500 A EP 02758500A EP 02758500 A EP02758500 A EP 02758500A EP 1436573 A1 EP1436573 A1 EP 1436573A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- surface level
- switch
- sensor
- level
- container
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 239000007788 liquid Substances 0.000 claims abstract description 37
- 239000000835 fiber Substances 0.000 claims abstract description 20
- 239000011521 glass Substances 0.000 claims abstract description 13
- 239000002360 explosive Substances 0.000 claims abstract description 5
- 238000012544 monitoring process Methods 0.000 description 6
- 239000004020 conductor Substances 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 230000007257 malfunction Effects 0.000 description 3
- 235000014676 Phragmites communis Nutrition 0.000 description 2
- 238000004880 explosion Methods 0.000 description 2
- 230000033001 locomotion Effects 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 239000013307 optical fiber Substances 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
- G01F23/0038—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm using buoyant probes
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
- G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
- G01F23/28—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring the variations of parameters of electromagnetic or acoustic waves applied directly to the liquid or fluent solid material
- G01F23/284—Electromagnetic waves
- G01F23/292—Light, e.g. infrared or ultraviolet
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
- G01F23/30—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by floats
- G01F23/76—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by floats characterised by the construction of the float
Definitions
- the invention relates to a surface switch as defined in the preamble of claim 1.
- the sensors used for the determination should have a structure such that they do not cause any risk of explosion during use.
- the surface level of such explosive liquids has previously been determined using either mechanical or electric devices.
- Such a mechanical surface level sensor may consist for instance of a float fixed to a wire cable, and then information about the move- ment of the float together with information about the surface level is transmitted via the wire cable outside the container.
- the surface level can also be determined by conducting compressed air into a pipe in the container, the pipe end being located under the liquid surface. As the liquid surface sinks, the pressure in the pipe decreases and an alarm of dropping surface level can be emitted.
- the implementation of such a system is expensive.
- Electric surface level sensors are represented e.g. by sensors of reed-relay type and surface switches suspended from their conductor.
- reed relay sensors a float floating on the liquid surface has been attached about the shaft.
- the shaft transmits the movement of the float to the shaft joint loca- tion, where there is a switch that is disconnected and transmits an electric signal further.
- a second sensor of reed relay type the shaft remains in position and the float surrounding the shaft moves along with the liquid surface. As the liquid surface rises, a magnet provided in the float disconnects the read relay located within the shaft.
- the float provided at the conductor end holds a switch, which is disconnected as the float position changes as a result of the liquid surface rising or sinking and transmits an electric signal forwards.
- the sensors have nevertheless to be manufactured in conformity with Exi protection requirements in order to avoid any risk of explosion. This is not always possible, and then a separate Exi relay has to be used, the sensor being connected via the safe current circuit of this to the measurement system. This increases the cost of the sensor and entails more complicated circuitry required for connecting the sensor. What is more, electric sensors usually do not have any self-diagnostics. There is no warning of damage to the sensor or its cable until damage actually occurs.
- the purpose of this invention is to provide a new surface switch, which does not have the shortcomings mentioned above.
- the surface switch of the invention has smaller size than previously known surface switches, and thus it can be used in containers having smaller holes. Moreover, the surface switch of the invention does not comprise electric components, and it can consequently be safely used in explosive spaces. Its manufacturing costs are also lower than those of a conventional Exi-protected electric switch.
- the surface switch of the invention does not have moving parts getting into contact with the liquid, and hence there will be no malfunctions caused by fouling. Should the switch or its wire cable fail, the malfunction is easily detected.
- figures la, lb and lc illustrate the surface switch of a preferred embodiment of the invention in cross-section, in horizontal and vertical positions
- FIGS. 2a and 2b illustrate the surface switch of a second preferred embodiment of the invention in cross-section, in horizontal and vertical positions
- figure 3 shows the use of a surface switch of a preferred embodiment of the invention for monitoring the surface level of a liquid.
- the surface switch in a preferred embodiment of the invention as shown in figures la, lb and lc comprises a float 1, an air space 2, a plug 3, an optic fibre 4, a mounting support 5, a glass ball 6, a support base 7 and a mirror 8.
- the surface switch in a second preferred embodiment of the invention as shown in figures 2a and 2b comprises a float 1, an air space 2, a plug 3, an optic fibre 4, a mounting support 5, a glass ball 6 and a support base 7.
- the optic fibre cable 11 of the surface switch is inserted into the container 15 through a hole in the upper surface of the container 15.
- the sensor 10 suspended from the end of the optic fibre cable 11 to the desired height.
- the sensor 10 is lowered to a height such that the sensor turns upside-down once the liquid surface has risen to the alarm level. If, again, it is desirable to receive an alarm about the container 15 being empty, the sensor 10 is lowered so as to float on the liquid surface on a height such that the sensor swings into upright position when the liquid surface sinks to the alarm level.
- the optic fibre cable 11 is inserted into the sensor 10 through a tight plug 3 provided at the end of the sensor 10.
- the optic fibre 4 is fixed to the mounting support 5 and the end of the optic fibre 4 is oriented towards a reflective surface, such as a mirror 8, or towards the other end of the optic fibre.
- a light beam is fed to the optic fibre cable 11 from the transmitter 13 of the control unit 12, the return of the light beam through the optic fibre cable 11 being detected in the receiver 14 of the control unit 12.
- the control unit 12 reports the surface level of the liquid to the user or, if necessary, gives an alarm at the upper or lower limit set for the surface level.
- the surface switch of a preferred embodiment of the invention shown in figure 1 provides information about the surface level in the container 15.
- the surface switch is fitted by suspending from the optic fibre cable 15 of the surface switch, at the desired height at the upper edge of the container 15.
- the float 1 of the surface switch will not be in contact with the liquid and the sensor 10 is in vertical position as shown in figure la.
- the glass ball 6 within the float is located in the centre of the support base 7.
- the glass ball 6 acts as a lens, and there will be double light beam intensity reflected from the mirror 8 to the optic fibre 4.
- the surface switch starts floating on the liquid surface owing to the buoyancy provided by the float 1.
- the position of the surface switch changes as shown in figure lc, and the glass ball 6 switches into a position between the mounting support 5 and the support base 7. There will then be a decrease in the intensity of the light beam reflected from the mirror 8.
- the sensor 10 of the surface switch has turned completely upside-down as shown in figure lb, the glass ball switches into a position in the centre of the mounting support 5.
- the glass ball 6 thus acts as a lens, the light beam reflected from the rnirror 8 will have high intensity.
- the control unit 12 infers the prevailing position of the sensor 10 and the surface level of the liquid in the container 10 from the intensity of the light beam returning through the optic fibre cable 10.
- high intensity corresponds to the upper limit of the surface level
- medium intensity corresponds to the lower limit of the surface level
- high intensity corresponds to midway between the alarm range surface levels.
- the surface switch of a second preferred embodiment of the invention shown in figure 2 may provide an alarm about the surface level of the liquid in the container 15 having reached either the upper or the lower limit. If information about the upper limit having been reached is desired, the sensor 10 should be lowered to such a level in the container 15 that the sensor turns into horizontal position as the liquid surface level reaches the upper limit. Accordingly, when it is desirable to receive information about the lower limit having been reached, the sensor 10 should be lowered to a level such that the sensor swings into vertical position as the liquid surface level reaches the lower limit.
- the float 1 on the liquid surface in the container 15 is in horizontal position as shown in figure 2b. Then the glass ball 6 is located between the mounting support 5 and the support base 7. Then there will be a decrease in the intensity of the light beam returning to the optic fibre through the glass ball 6 acting as a lens.
- the sensor 10 turns into upright position as shown in figure 2a, and the glass balls 6 switches into a position in the centre of the support base 7.
- the light beam returning to the optic fibre 4 will then pass through the central point of the glass ball 6 and the returning light beam will have high inten- sity.
- the liquid surface level is inferred in a manner corresponding to the case of figure 1.
- high intensity corresponds to the lower limit of the surface level
- high intensity corresponds to the upper limit of the surface level.
- surface switches of the invention can be used in the measurement of the sur- face level of granular explosive material, such as grain stored in a grain silo. Besides alarms about upper and lower limits, all of the sensors mentioned above can be used in controlling solenoid valves or pumps.
Landscapes
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- General Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Thermal Sciences (AREA)
- Level Indicators Using A Float (AREA)
Abstract
Description
Claims
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FI20011798A FI116421B (en) | 2001-09-12 | 2001-09-12 | Level switch |
FI20011798 | 2001-09-12 | ||
PCT/FI2002/000731 WO2003023333A1 (en) | 2001-09-12 | 2002-09-12 | Surface switch for determining the surface level |
Publications (1)
Publication Number | Publication Date |
---|---|
EP1436573A1 true EP1436573A1 (en) | 2004-07-14 |
Family
ID=8561879
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP02758500A Withdrawn EP1436573A1 (en) | 2001-09-12 | 2002-09-12 | Surface switch for determining the surface level |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP1436573A1 (en) |
FI (1) | FI116421B (en) |
WO (1) | WO2003023333A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN111473838A (en) * | 2020-05-13 | 2020-07-31 | 北京市万智生科技有限公司 | Floating water level meter for measuring water storage level of closed or semi-closed water pool |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CH647320A5 (en) * | 1982-04-02 | 1985-01-15 | Cortaillod Cables Sa | Optical assembly for liq. level signalling in reservoir - uses optical fibre to direct light onto ball in sensor mounted on float arm |
DE68903183T2 (en) * | 1988-03-15 | 1993-03-18 | Imo Ind Inc | FIBER OPTICAL LEVEL SENSOR FOR DISCRETE OR CONTINUOUS DISPLAY OF A LIQUID LEVEL. |
CH680020A5 (en) * | 1990-04-02 | 1992-05-29 | Hectronic Ag | |
US5743135A (en) * | 1993-08-27 | 1998-04-28 | Vlsi Technology, Inc. | Optical-fiber liquid-level monitor |
FI112703B (en) * | 2000-04-11 | 2003-12-31 | Matti Kari | level switch |
-
2001
- 2001-09-12 FI FI20011798A patent/FI116421B/en not_active IP Right Cessation
-
2002
- 2002-09-12 EP EP02758500A patent/EP1436573A1/en not_active Withdrawn
- 2002-09-12 WO PCT/FI2002/000731 patent/WO2003023333A1/en not_active Application Discontinuation
Non-Patent Citations (1)
Title |
---|
See references of WO03023333A1 * |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN111473838A (en) * | 2020-05-13 | 2020-07-31 | 北京市万智生科技有限公司 | Floating water level meter for measuring water storage level of closed or semi-closed water pool |
CN111473838B (en) * | 2020-05-13 | 2021-12-28 | 北京市万智生科技有限公司 | Floating water level meter for measuring water storage level of closed or semi-closed water pool |
Also Published As
Publication number | Publication date |
---|---|
WO2003023333A1 (en) | 2003-03-20 |
FI20011798A (en) | 2003-03-13 |
FI116421B (en) | 2005-11-15 |
FI20011798A0 (en) | 2001-09-12 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US5117693A (en) | Liquid level sensor | |
US4836632A (en) | Fiber optic liquid level sensor | |
US5294917A (en) | Liquid level sensor using float and magnetic means | |
US8314711B2 (en) | Optical switch | |
US5950487A (en) | Gauge for measuring liquid levels | |
US20070205907A1 (en) | Switch assembly and system for high-level monitoring | |
CA2687514A1 (en) | An optical switch | |
US8149122B2 (en) | Liquid level detection system with floating RFID tag | |
US7714732B2 (en) | Optical switch | |
US4384184A (en) | Explosion-proof device for measuring liquid levels | |
US4610165A (en) | Fluid level sensor | |
US20130120155A1 (en) | Monitoring of floating roof tank | |
US5000044A (en) | Fluid level sensor | |
CA2321771A1 (en) | Liquid level controller | |
JP2006500275A (en) | Vehicle height change detection system | |
CA1079832A (en) | Liquid-level float switch construction | |
US6688171B2 (en) | Flexible contact element for contactless signal acquisition | |
EP1436573A1 (en) | Surface switch for determining the surface level | |
EP1040324B1 (en) | Liquid level detector | |
FI112703B (en) | level switch | |
WO2010093929A1 (en) | An optical pressure activated device | |
EP4180776B1 (en) | Device for detecting at least one level of a fluid of a tank | |
EP3869167B1 (en) | Valve arrangement for a guided wave radar level gauge | |
CN217845329U (en) | Novel floating ball connecting rod device for high-low liquid level alarm device | |
CN2145987Y (en) | Optical cable contactless material level switch |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
17P | Request for examination filed |
Effective date: 20040408 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR IE IT LI LU MC NL PT SE SK TR |
|
AX | Request for extension of the european patent |
Extension state: AL LT LV MK RO SI |
|
17Q | First examination report despatched |
Effective date: 20070327 |
|
GRAP | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOSNIGR1 |
|
RIC1 | Information provided on ipc code assigned before grant |
Ipc: G01F 23/292 20060101ALI20151103BHEP Ipc: G01F 23/76 20060101AFI20151103BHEP Ipc: G01F 23/00 20060101ALI20151103BHEP |
|
INTG | Intention to grant announced |
Effective date: 20151126 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
|
18D | Application deemed to be withdrawn |
Effective date: 20160407 |