Preheating programmer for buses at depot - comprises clock to switch on heater to attain demanded temp. just prior to service use

摘要

The arrangement utilises a clock (1) connected to a switch circuit joined to another clock (4) in a temp. and time calculator unit (2). A temp. sensor (3) located in the vehicle provides an input to a circuit (6) which compares the value with a demand temp. value from an adjustable control (7). A second comparator (5) receives an input from the clock circuit to signal that heating is required for a given period. It also receives a signal representing the difference between the actual and demanded temps. This comparator activates the heater (M) to achieve the required temp. Temperature control for a number of buses at a depot is provided by a common calculator programmed from a keyboard to control the various heater units.