Thermal measuring and testing – Transformation point determination
Patent
1996-12-09
1998-07-28
Bennett, G. Bradley
Thermal measuring and testing
Transformation point determination
374 25, G01N 2508
Patent
active
057854254
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a device for sensing the boiling point of a fluid and, more especially relates to a device for conveniently sensing the boiling point of hydraulic fluid, for example for testing the quality of brake fluid of a motor vehicle.
A hydraulic fluid such as motor vehicle brake fluid is hygroscopic, i.e. absorbs water (moisture). Water absorption has, of course, the effect of considerably reducing the boiling point of the fluid, with the result that in the case of motor vehicles, heavy vehicle braking may give rise to sufficient heat generation to boil the brake fluid thereby resulting in vapour entrapment in the fluid which could dangerously reduce braking performance.
Consequently, there is the need to test the quality brake fluid by sensing the boiling point of the fluid, so that the sensed value can be compared with an accepted standard to evaluate the fluid quality. Sensing devices are known for sensing the boiling point of fluid and especially the boiling point (and quality) of brake fluid. Basically, these devices include a heater to heat a quantity of the fluid to boiling point and a temperature sensor to sense the boiling temperature. Some of these devices, e.g. as shown in U.S. Pat. No. 4,958,937, require a sample of fluid to be removed from the vehicle reservoir for testing, and the subsequent testing procedure is of a somewhat delicate laboratory-like nature. This is inconvenient and is not readily acceptable for everyday garage operations. To meet this problem, other sensing devices have been provided capable of testing directly at the fluid reservoir, an example of such a device being shown in U.S. Pat. No. 4,484,823 (WO90 12311), but the arrangement of the heating means in the device of U.S. Pat. No. 4,484,823 precludes prompt temperature sensing. The device shown in International Application WO90/12311 overcomes this problem by providing a hand-held sensor which, when inserted into the fluid to be tested, traps a small portion of the fluid in a semi-encapsulated chamber in a probe part of the device for heating. The device, however, relied very much on correct depth immersion in the fluid. It is an object of the present invention to provide a fluid boiling-point sensing device which is capable of being hand-held and which can be used in a more convenient manner to sense the boiling points of fluids directly at a fluid reservoir, e.g. in a vehicle brake fluid reservoir.
Therefore, the present invention is provides a fluid boiling-point measuring device as set out in the appended claim 1.
Therefore, the first aperture means on the outer surface of the probe constitute to control means controlling the level of the fluid in the housing for different degrees of immersion of the probe and further said control means serves to keep the test fluid in the housing at a set level by trapping a quantity of air within the probe above the aperture means such as to maintain a fluid/air boundary at a set level.
Preferably further aperture means are located below the bottom of the temperature sensor.
Preferably the probe member is of cylindrical form, said upper and lower housing portions defining cylindrical chambers, a plug being providd to close the top of the chamber of the upper housing portion. The probe member may comprise a single cylindrical casing, with said first aperture means located on a bottom wall of the casing. Alternatively the probe member may be of radially spaced double-wall form with said second aperture means on the outer wall and additional fluid aperture means on the inner wall located above said second aperture means. Either of the first and second aperture means may comprise openings of a restricted form. The heating means preferably comprise an electrical heater supplied with power from an electrical battery while the temperature sensor which can comprise a thermocouple device is preferably linked to suitable monitoring and presentation means for registering the measured temperature value. The probe member is preferably part of a self-contained hand-held u
REFERENCES:
patent: 1443537 (1923-01-01), Hortvet
patent: 3276262 (1966-10-01), Sapoff et al.
patent: 3940988 (1976-03-01), Reed
patent: 4781469 (1988-11-01), Turon-Lagot
patent: 4958937 (1990-09-01), Lohberg et al.
patent: 4987749 (1991-01-01), Baier
patent: 5380091 (1995-01-01), Buchanan
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