GB1596520A - Processes for determining corrosivity of automobile coolant - Google Patents
Processes for determining corrosivity of automobile coolant Download PDFInfo
- Publication number
- GB1596520A GB1596520A GB54314/77A GB5431477A GB1596520A GB 1596520 A GB1596520 A GB 1596520A GB 54314/77 A GB54314/77 A GB 54314/77A GB 5431477 A GB5431477 A GB 5431477A GB 1596520 A GB1596520 A GB 1596520A
- Authority
- GB
- United Kingdom
- Prior art keywords
- electrode
- steel
- niobium
- gold
- zinc
- 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.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60H—ARRANGEMENTS OF HEATING, COOLING, VENTILATING OR OTHER AIR-TREATING DEVICES SPECIALLY ADAPTED FOR PASSENGER OR GOODS SPACES OF VEHICLES
- B60H1/00—Heating, cooling or ventilating [HVAC] devices
- B60H1/32—Cooling devices
- B60H1/3204—Cooling devices using compression
- B60H1/3229—Cooling devices using compression characterised by constructional features, e.g. housings, mountings, conversion systems
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B47/00—Arrangements for preventing or removing deposits or corrosion, not provided for in another subclass
- F25B47/003—Arrangements for preventing or removing deposits or corrosion, not provided for in another subclass for preventing corrosion
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N17/00—Investigating resistance of materials to the weather, to corrosion, or to light
- G01N17/02—Electrochemical measuring systems for weathering, corrosion or corrosion-protection measurement
Description
(54) PROCESSES FOR DETERMINING CORROSIVITY OF
AUTOMOBILE COOLANT
(71) We, TEXAS INSTRUMENTS INCORPORATED, a Company organized according to the laws of the State of Delaware, United States of America, of 13500 North
Central Expressway, Dallas, Texas, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:
This invention relates generally to vehicular cooling systems and more particularly to monitoring the effectiveness of the corrosion inhibiting characteristic of coolant fluid used in such systems.
Vehicular cooling systems are composed of several components including the radiator, circulating pump, passages in the motor block and associated tubing. Since the system is composed of metallic parts there is a need to prevent or at least mitigate corrosion in order to prolong the useful life of the system. To this end it has become common practice to add chemical substances to the coolant fluid which tend to inhibit corrosion of the metal surfaces which come in contact with the fluid. Such substances are known as inhibitors and generally form a film on the metal surfaces thereby protecting them from degradation.Thus commercially available permanent antifreeze include an inhibitor which is highly successful in preventing corrosion; however, over the course of time the corrosion inhibiting characteristic of the fluid can become less effective due to chemical decomposition of the inhibitor, leakage or boiling of the coolant fluid with subsequent replenishment with water.
It is therefore recommended procedure to periodically change the coolant fluid with fresh permanent antifreeze. This of course can be wasteful if the corrosion inhibiting characteristic of the coolant fluid is still effective. On the other hand the tendency to employ aluminium radiators in some automobiles has exacerbated the problem since aluminium radiators corrode much more quickly than conventional copper radiators.
According to the present invention, there is provided:
A process for indicating when the corrosion inhibitor in a vehicular cooling fluid becomes ineffective to prevent corrosion of the cooling system housing, the process including: establishing first and second electro-chemical potentials by disposing first and second spaced electrodes of dissimilar material in contact with the cooling fluid and coupling voltage responsive means to the electrodes for providing an output corresponding to the difference in potential between the two electrodes, the voltage responsive means having sufficiently high impedance that there is essentially no current flow between the electrodes.
The first electrode can be a reference electrode and the second electrode can be composed of steel, zinc, niobium, gold, lead, titanium, copper or nickel.
The second electrode can be composed of steel.
The first electrode can be composed of silver.
The voltage responsive means can include switching means which actuates when the difference in potential exceeds a predetermined threshold level.
The threshold level can be approximately -0.3 volts.
By way of example only, certain illustrative embodiments of the invention will now be described with reference to the accompanying drawings, in which:
Figure 1 is a schematic side elevation of a vehicular cooling system in which a sensor is mounted to monitor the effectiveness of the inhibiting characteristic of the cooland fluid and a meter is mounted in the dashboard to provide visual indication of such effectiveness;
Figure 2 is an enlarged cross sectional side elevation view of the Figure 1 sensor;
Figure 3 is a cross sectional view of a portion of the cooling system wall showing the
Figure 2 sensor mounted therein and connected to a high impedance voltmeter; and
Figure 4 is a schematic electrical circiut useful with the Figure 2 sensor.
Briefly, in the system shown in the drawings the effectiveness of the corrosion inhibiting characteristic of the cooland fluid is monitored and measured by means of a high impedance potential measuring circuit employing first and second electrochemical electrodes of dissimilar material placed in contact with the coolant fluid. When the inhibiting characteristic is effective a first range of electrical potential exists between the electrodes; however, when the inhibiting characteristic becomes ineffective for any reason a second range of electrical potential exists therebetween. An output signal upon the debilitation of the corrosion inhibiting characteristic of the coolant fluid can be employed to actuate a switch to provide visual or audible indication or to activate an inhibitor replenishment means.Thus when the potential reaches a threshold level as it moves into the second range visual (such as a light) or auditory indicating means can be activated or a continuous read out as with a high impedance voltmeter mounted in the dashboard can be provided. The sensor used in monitoring the inhibiting ability of the coolant fluid is inexpensive, reliable and long lived.
Referring to the drawings, 10 indicates a vehicular cooling system comprising a radiator 12, cylinder block 14, cylinder head 16, tubing lines 18 and 20 connecting the radiator respectively to block 14 and head 16, circulating pump 22 in line 18 and thermostat 24 on line 20. It will be appreciated that as far as described in the preceding sentence the system conforms to a conventional cooling system in use in motor vehicles. A sensor 30 extends through the wall of cylinder block 14 (see Figure 1 and Figure 3) so that its distal end is adapted to come in contact with the coolant fluid circulating in the system. The darts shown in Figure 1 indicate the circulation of the coolant liquid. Sensor 30 comprises a tubular housing having a bore 32 extending along its longitudinal axis and is provided with a threaded portion 34 to enable it to be mounted in a complimentary threaded bore.Head 36 is preferably hexagonally configured to facilitate insertion in bore 38 of the cylinder block wall. First and second electrode wires 40, 42 are mounted in bore 32 of the sensor and maintained in spaced relation to each other and to the wall of bore 32 by any conventional electrically insulative potting material 44 which is non-reactive with the cooling fluid.
Electrodes 40 and 42 extend beyond distal end 46 of sensor 30 so that they will be inundated by the coolant fluid. Electrodes 40,42 are connected to a high impedance voltmeter 54 which is conveniently mounted in dash 56 of the vehicle.
As seen in Figure 4 the effectiveness of the inhibitor can be monitored employing a potential measuring circuit comprising a high impedance voltage follower 60, which receives inputs from electrode 40,42 coupled to amplifier 62 which in turn is coupled to voltage comparator 64. The threshold of comparator 64 is set at junction 66 of voltage divider 68. Comparator 64 is coupled to the base of NPN transistor 70 whose collector is coupled to light emitting diode 72.
The particular configuration of sensor 30 is a matter of choice as long as it disposes spaced first and second electrodes in contact with the coolant fluid. Further, although the electrodes are shown to be in wire form other electrode configurations are possible. The first electrode, element 40, serves as a reference electrode and may be any standard commercial reference electrode such as the calomel family, the silver family includingAgl Ag halide and AgtAgO, the copper family such as CuiCu halide and CuICuSO4 or other stable reference electrode. In some cases metallic silver exposed to the coolant liquid can be used as a reference potential since the metal is in contact with the oxide and a stable reference potential exists.
The second electrode element 42 can be composed of low carbon steel, copper, nickel, zinc, titanium, niobium, platinum, gold, lead or tin. The demarcation between the two ranges of potentials indicating effective and ineffective corrosion inhibiting characteristics varies among the materials with a particularly good demarcation existing for steel. As seen in Table I in which reference electrode 40 is a fine silver wire and the second electrode 42 is a) steel and b) copper a threshold level of -0.300 volts will be very effective in providing the desired indication of effectiveness of the inhibiting characteristic for steel vs silver electrode.
TABLE I
a b 1. H2O -0.720 -0.035 2. 15% solution with H2O -0.690 +0.039
of ethylene-glycol 3. 30% solution with H2O -0.698 +0.080
of ethylene-gylcol 4. 50% solution with H2O -0.670 +0.090
of ethylene-glycol 5. 15% solution with H2O -0.236 -0.110
of permanent anti-freeze 6. 30% solution with H2O -0.210 -0.186
of permanent anti-freeze 7. 50% solution with H2O -0.185 -0.110
of permanent anti-freeze
The data included in Table 1 was obtained using a reference electrode of silver and an electrode of steel for column (a) and copper for column (b), and DuPont de Nemours "Telar" antifreeze.
The potential of steel in different commercially available antifreezes is shown in Tables II a and b. The particular antifreezes are identifed as follows:
Brand Name Distributor Identification
A Zerex PPG Industries, Inc.
B Ford Ford Marketing Corporation 8A-19549-A
C Prestone II Union Carbide Corporation AF-542
(registered Trade Mark)
D Dowgard Dow Chemical Company D675
(registered Trade Mark)
E Pennzoil Pennzoil Company, Oil City PA
F Shellzone Shell Oil Company
(registered Trade Mark)
G Mac's Radicool Mac's Super Gloss Co., Inc. 4k1800 H Pah-nol Houghton Chemical Corp.
Typically inhibitors in commercial antifreezes include varying percentages of borate, phosphate, nitrate, silicate and mercaptobenzothiazole TABLElIa Potential of Steel Electrode 42 in Antifreeze Solutions (25%)
Reference Reference Reference
Electrode 40 Electrode 40 Electrode 40
Type Ag SCE AglAgCI
Tap Water -0.581 -0.520 -0.645 25% Ethylene Glycol -0.550 -0.510 -0.590 (No Inhibitor)
A -0.210 -0.245 -0.390
B -0.160 -0.280 -0.275
C -0.205 -0.285 -0.295
D -0.205 -0.280 -0.285
E -0.230 -0.350 -0.300
F -0.190 -0.320 -0.310
G -0.135 -0.200 -0.250
TABLE IIb
Potential of Steel Electrode 42 in Antifreeze Solutions (50%)
Reference Reference Reference
Electrode 40 Electrode 40 Electrode 40
Type Ag SCE AglAgC1 Tap Water -0.581 -0.520 -0.645 50% Ethylene Glcyol -0.520 -0.590 -0.580 (No Inhibitor)
A -0.220 -0.275 -0.300
B -0.120 -0.235 -0.235
C -0.205 -0.285 -0.280
D -0.175 -0.230 -0.230
E -0.160 -0.290 -0.305
F -0.200 -0.310 -0.295
G -0.150 -0.205 -0.250
Table III shows the potential of steel in 25% ethylene glycol and 25% ethylene glycol plus commercial inhibitors at concentrations recommended by the manufacturer.
TABLE III
Reference Reference Reference
Electrode 40 Electrode 40 Electrode 40
Type Ag SCE AglAgCI
None -0.560 -0.510 -0.630
k -0.150 -0.145 -0.265
None -0.550 -0.490 -0.625
1 -0.195 -0.280 -0.320
None -0.540 -0.585 -0.600
m -0.295 -0.220 -0.195
None -0.545 -0.480 -0.625
n -0.255 -0.250 -0.350
The Table III the brand name of the inhibitors are Shell Oil Company for k, Solder Seal for l, Prestone form and Valvoline (registered Trade Mark) for n.
As mentioned above the demarcation between the ranges of potentials indicating effective and ineffective corrosion inhibiting characteristics varies with different materials.
Table IV a, b and c shows the potentials of a number of different electrode 42 metals versus a reference electrode 40 of Ag/AgCl for Table IVa, saturated calomel for Table IV b and silver wire for Table IV c.
TABLEIVa 25% Pahnol 50% Pahffol Metal Tap Water Antifreeze Antifreeze
Steel -0.645 -0.330 -0.247
Nickel -0.450 -0.420 -0.385
Zinc -1.098 -0.940 -0.756
Copper -0.157 -0.020 0.000
Titanium -0.350 -0.295 -0.318
Niobium -0.416 -0.215 -0.171
Gold -0.226 -0.075 -0.098
Lead -0.649 -0.525 -0. 559
TABLE IV b
25% Pahnol 50% Pahnol
Metal Tap Water Antifreeze Antifreeze
Steel -0.520 -0.250 -0.190
Zinc -0.920 -0.825 -0.690
Titanium -0.220 -0.370 --0.260 Niobium -0.160 -0.155 -0.110
Gold -0.090 0.000 -0.030
Lead -0.545 -0.430 -0.506
TABLE IV c
25% Pahnol 50% Pahnol
Metal Tap Water Antifreeze Antifreeze
Steel -0.581 -0.260 -0.138
Nickel -0.390 -0.345 -0.285
Zinc -1.035 -0.830 -0.654
Copper -0.086 +0.045 +0.124
Titanium -0.295 -0.260 -0.205
Niobium -0.287 -0.120 -0.058
Gold -0.110 +0.005 +0.005
Lead -0.635 -0.415 -0.448
From the above tables it will be seen that the most effective material for electrode 42 is steel while zinc, Niobium and gold are acceptable. Lead, titanium, copper and nickel could be used but are not as effective as steel, zinc, Niobium and gold and thus would require more sophisticated electrical circuitry for effective use.
Various modifications and changes can be made to what has been described without departing from the scope of the invention as defined in the appended claims.
WHAT WE CLAIM IS:
1. A process for indicating when the corrosion inhibitor in a vehicular cooling fluid becomes ineffective to prevent corrosion of the cooling system housing, the process including: establishing first and second electrochemical potentials by disposing first and second spaced electrodes of dissimilar material in contact with the cooling fluid and coupling voltage responsive means to the electrodes for providing an output corresponding to the difference in potential between the two electrodes, the voltage responsive means having sufficiently high impedance that there is essentially no current flow between the electrodes.
2. A process as claimed in claim 1, wherein the first electrode is a reference electrode and the second electrode is composed of steel, zinc, Niobium, gold, lead, titanium, copper or nickel.
3. A process as claimed in claim 1 or 2, wherein the second electrode is composed of steel.
4. A process as claimed in any of claims 1 to 3, wherein the first electrode is composed of silver.
5. A process as claimed in any preceding claim, wherein the voltage responsive means includes switching means which actuates when the difference in potential exceeds a predetermined threshold level.
6. A process as claimed in claims 4 and 5, wherein the threshold level is approximately -0.3 volts.
7. A process for indicating when the corrosion inhibitor in a vehicular cooling fluid becomes ineffective to prevent corrosion of the cooling system housing, the process being substantially as herein described with reference to and as illustrated by the accompanying drawings.
8. A process as claimed in claim 7 substantially as herein described with reference to and as illustrated by Figures 1 and 2 of the accompanying drawings.
9. A process as claimed in claim 8 substantially as herein described with reference to and as illustrated by Figure 3 of the accompanying drawings.
10. A process as claimed in claim 8 substantially as herein described with reference to and as illustrated by Figure 4 of the accompanying drawings.
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (10)
1. A process for indicating when the corrosion inhibitor in a vehicular cooling fluid becomes ineffective to prevent corrosion of the cooling system housing, the process including: establishing first and second electrochemical potentials by disposing first and second spaced electrodes of dissimilar material in contact with the cooling fluid and coupling voltage responsive means to the electrodes for providing an output corresponding to the difference in potential between the two electrodes, the voltage responsive means having sufficiently high impedance that there is essentially no current flow between the electrodes.
2. A process as claimed in claim 1, wherein the first electrode is a reference electrode and the second electrode is composed of steel, zinc, Niobium, gold, lead, titanium, copper or nickel.
3. A process as claimed in claim 1 or 2, wherein the second electrode is composed of steel.
4. A process as claimed in any of claims 1 to 3, wherein the first electrode is composed of silver.
5. A process as claimed in any preceding claim, wherein the voltage responsive means includes switching means which actuates when the difference in potential exceeds a predetermined threshold level.
6. A process as claimed in claims 4 and 5, wherein the threshold level is approximately -0.3 volts.
7. A process for indicating when the corrosion inhibitor in a vehicular cooling fluid becomes ineffective to prevent corrosion of the cooling system housing, the process being substantially as herein described with reference to and as illustrated by the accompanying drawings.
8. A process as claimed in claim 7 substantially as herein described with reference to and as illustrated by Figures 1 and 2 of the accompanying drawings.
9. A process as claimed in claim 8 substantially as herein described with reference to and as illustrated by Figure 3 of the accompanying drawings.
10. A process as claimed in claim 8 substantially as herein described with reference to and as illustrated by Figure 4 of the accompanying drawings.
2 SHEETS
COMPLETE SPECIFICATION
This drawing Is a reproductlon of
the Originol on a reduced scale
Sheet 1
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US75667877A | 1977-01-04 | 1977-01-04 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1596520A true GB1596520A (en) | 1981-08-26 |
Family
ID=25044576
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB54314/77A Expired GB1596520A (en) | 1977-01-04 | 1977-12-30 | Processes for determining corrosivity of automobile coolant |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPS5493737A (en) |
| DE (1) | DE2800326A1 (en) |
| FR (1) | FR2376383A1 (en) |
| GB (1) | GB1596520A (en) |
| IT (1) | IT1155753B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2180067A (en) * | 1985-09-04 | 1987-03-18 | Corrocean As | Probe for corrosion testing |
| GB2222609A (en) * | 1988-08-04 | 1990-03-14 | Albright & Wilson | Fabric conditioners |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4147596A (en) * | 1977-12-30 | 1979-04-03 | Texas Instruments Incorporated | Method and apparatus for monitoring the effectiveness of corrosion inhibition of coolant fluid |
| JPS57168727U (en) * | 1981-04-20 | 1982-10-23 | ||
| DE3515767A1 (en) * | 1985-05-02 | 1986-11-06 | Alfred Teves Gmbh, 6000 Frankfurt | Device for determining and monitoring the condition, the state and the filling level of a hydraulic fluid |
| DE3703439C1 (en) * | 1987-02-05 | 1988-02-11 | Daimler-Benz Ag, 7000 Stuttgart, De | Anticorrosion medium effectiveness monitor - has particle separator responding to density difference for cooling system of IC engine |
| DE4443021C1 (en) * | 1994-12-02 | 1996-04-11 | Josef Dagn | Corrosion protection characteristics measuring system for engine coolant |
| EP0989400A1 (en) * | 1998-09-03 | 2000-03-29 | R. E. Davis Chemical Corporation | Method and apparatus for measuring the acid level of hydraulic fluid in a hydraulic system |
| JP5396844B2 (en) * | 2008-12-12 | 2014-01-22 | 日産自動車株式会社 | Cooling system |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3166485A (en) * | 1963-01-31 | 1965-01-19 | Exxon Research Engineering Co | Corrosion electro-potentiometer probe |
| US3558462A (en) * | 1968-10-03 | 1971-01-26 | Petrolite Corp | Probe assembly for corrosion tests |
| US3660249A (en) * | 1970-02-05 | 1972-05-02 | Magna Corp | Method and apparatus for determining both the average corrosion rate, and the pitting tendency, substantially independently of the resistance of the electrolyte |
| US3725212A (en) * | 1970-03-07 | 1973-04-03 | Mitsubishi Motors Corp | Method for testing radiator-tube-clogging property of antifreezing coolants |
| US3717566A (en) * | 1971-11-11 | 1973-02-20 | Petrolite Corp | Corrosion ratemeter |
| JPS4949327U (en) * | 1972-08-07 | 1974-04-30 | ||
| GB1545487A (en) * | 1975-03-27 | 1979-05-10 | Ici Ltd | Method and probe assembly for examination of protective coatings |
| CS199051B1 (en) * | 1975-04-28 | 1980-07-31 | Josef Polak | Method of polarizing potential measuring of constructions from carbon steel placed in electrolyte in electric current field and device for making this method |
-
1977
- 1977-12-30 GB GB54314/77A patent/GB1596520A/en not_active Expired
- 1977-12-30 FR FR7739832A patent/FR2376383A1/en active Granted
-
1978
- 1978-01-02 IT IT47508/78A patent/IT1155753B/en active
- 1978-01-04 JP JP9778A patent/JPS5493737A/en active Granted
- 1978-01-04 DE DE19782800326 patent/DE2800326A1/en active Granted
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2180067A (en) * | 1985-09-04 | 1987-03-18 | Corrocean As | Probe for corrosion testing |
| GB2222609A (en) * | 1988-08-04 | 1990-03-14 | Albright & Wilson | Fabric conditioners |
Also Published As
| Publication number | Publication date |
|---|---|
| DE2800326C2 (en) | 1988-01-07 |
| FR2376383A1 (en) | 1978-07-28 |
| IT7847508A0 (en) | 1978-01-02 |
| FR2376383B1 (en) | 1984-04-27 |
| IT1155753B (en) | 1987-01-28 |
| JPS6157451B2 (en) | 1986-12-06 |
| DE2800326A1 (en) | 1978-07-13 |
| JPS5493737A (en) | 1979-07-25 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed [section 19, patents act 1949] | ||
| PE20 | Patent expired after termination of 20 years |
Effective date: 19971229 |