| WO/1989/000680 | DEVICE FOR INDICATING THE POSITION OF A FLUID WHICH SPREADS THROUGH A BODY |
| JPS59210336 | CALIBRATION ALARM DEVICE |
| AU6534780A | 1981-06-18 | |||
| CH654413A5 | 1986-02-14 | |||
| US3906797A | 1975-09-23 | |||
| US4627742A | 1986-12-09 |
| 1. | 1 but with additional temperature sensitive devices A chillhour meter as claim 2 but with additional time counter devices. |
| 2. | A chillhour meter substantially as herein described with reference to the accompaning specification. SUBSTITUTE SHEET . . |
This invention relates to improvements in the measurement of the amount of chilling that deciduous plants receive in their dormancy period.
Knowledge of the total chill received assists in making decisions as to the suitability of varieties and the application of growth regulating sprays such as cyanamide.
Other instruments used to assess the chill include:
(1) ' I±ijiimum-Maximum thermometers which have the disadvantages of requiring daily attention to record and reset.
(ii) Instantaneous temperature recorders with problems associated with ink and chart changing and interpretation of results.
These problems are overcome by the Chill-hour meter which indicates the total time that the plants were within a particular temperature range of interest by energising a time meter from a power source through a temperature sensitive device (set at temperature of interest).
In one form of the invention an hour meter is energised from a battery through a thermostat which is adjusted to the temperature of interest (usually 7°C) whereby the contact will be closed at any temperature below the setting thereby energising the meter to total the time below the set temperature.
As the effect of chilling ceases at lower temperatures (usually below 0°C) then another form of the invention can be used in areas where the temperature drops below 0°C for the significant periods. In this form of the invention a second (lower range) thermostat is used whose contact is close
when the temperature is above that of the set temperature. The contacts of the thermostats are connected in series so that the hour meter only records the time that tne temperature was in the range between the set points of the two thermostats.
As higher temperatures can have the effect to negate chilling another form of the invention is to provide a 2nd hour meter with its associated thermostat whereby a contact closes when the temperature is above the set temperature (usually 18°C) so that the time above this temperature can be considered when assessing the chill.
The components are connected and mounted in a suitable case for exposure to the environment.