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US 4,775,776 AGranted
Multi stage heater
AssigneeElectrovert Ltd.
InventorsArmin Rahn, Sabi Avramescu, Marcel Drouin
Life of this patent
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AssigneeElectrovert Ltd.
InventorsArmin Rahn, Sabi Avramescu, Marcel Drouin
Estimating the term…
A multi stage heater heats items on a conveyor so that they follow a predetermined temperature profile. The heater is used for printed circuit boards or the like when heated for soldering and avoids thermal gradients that can occur with heating different materials. The heater has a first heater for applying a first quantity of heat to items on the conveyor, a temperature sensing device for determining temperature of items leaving the first heater, a second heater downstream of the first heater and a control system which compares signals from the temperature sensing device with a predetermined temperataure profile to produce a first control output to control the first heater and a second control output to control the second heater so that items passing through the heater follow the predetermined temperature profile.
A heater for use in heating items on a conveyor to follow a predetermined temperature profile, the heater comprising first heater means adjacent the conveyor for applying a first quantity of heat to the items, at least one temperature sensing device adjacent the conveyor for deriving signals indicative of the temperature of the items, but not the temperature of the heater means, as they exit from the first heater means, second heater means adjacent the conveyor and downstream of the first heater means for applying a second quantity of heat to the items, and control device for comparing signals indicative of the temperature of the items with the predetermined temperature profile, the control means having an input supplied by the signals from the temperature sensing means, a first control output from the control means deriving signals to control heat supplied by the first heater means to affect the temperature of the items exiting from the first heater means, a second control output from the control means deriving signals to control heat supplied by the second heater means to affect the temperature of the items exiting from the second heater means, the signals from the first control output and the second control output correlated by the control means so the items exiting from the second heater means are approximately in accordance with the predetermined temperature profile.
A heater for use in heating items on a conveyor in a stabilized heat environment to follow a predetermined temperature profile, the heater comprising a plurality of heater means adjacent the conveyor for applying heat to the items, the heater means spaced along the conveyor, plurality of temperature sensing devices adjacent the conveyor and located downstream of each of the heater means, the temperature sensing devices deriving signals indicative of the temperature of the items but not the temperature of the heater means exiting from the heater means,
A process for producing a predetermined temperature profile for a circuit board transported through at least two heat zones, comprising the steps of:
A heater for use in heating items on a conveyor to follow a predetermined temperature profile, the heater comprising first heater means adjacent the conveyor for applying a first quantity of heat to the items, second heater means adjacent the conveyor and downstream of the first heater means for applying a second quantity of heat to the items, third heater means adjacent the conveyor and downstream of the second heater means for applying a third quantity of heat to the items, at least one temperature sensing device adjacent the conveyor for deriving signals indicative of the temperature of the items but not the temperature of the heater means as they exit from at least one of the heater means, and control means for comparing signals indicative of the temperature of the items with the predetermined temperature profile, the control means having an input supplied by the signals from the temperature sensing device, a first control output from the control means deriving signals to control heat supplied by the first heater means to affect the temperature of the items exiting from the first heater means, a second control output from the control means deriving signals to control heat supplied by the second heater means to affect the temperature of the items exiting from the second heater means, a third control output from the control means deriving signals to control heat supplied by the third heater means to affect the temperature of the items exiting from the third heater means, the signals from the first control, output the second control output and the third control output correlated by the control means so the items exiting from the third heater means are approximately in accordance with the predetermined temperature profile.
A heater for use in heating items on a conveyor in a stabilized heat environment to follow a predetermined temperature profile, the heater comprising at least threeheater means adjacent the conveyor for applying heat to the items, the heater means spaced along the conveyor, at least one temperature sensing device adjacent the conveyor and located downstream of at least one of the heater means, the temperature sensing device deriving signals indicative of the temperature of the items but not the temperature of the heater means exiting from the heater means,
A heater for use in heating items on a conveyor to follow a predetermined temperature profile, the heater comprising a first heater means adjacent the conveyor for applying a first quantity of heat to the items, second heater means adjacent the conveyor and downstream of the first heater means for applying a second quantity of heat to the items, at least one temperature sensing device adjacent the conveyor for deriving signals indicative of the temperature of the items but not the temperature of the heater means as they exit from at least one of the heater means, and control means for comparing signals indicative of the temperature of the items with the predetermined temperature profile, the control means having an input supplied by the signals from the temperature sensing device, a first control output from the first control means deriving signals to control heat supplied by the first heater means to affect the temperature of the items exiting from the first heater means, a second control output from the control means deriving signals to control heat supplied by the second heater means to affect the temperature of the items exiting from the second heater means, the signals from the first control output and the second control output correlated by the control means so the items exiting from the second heater means are approximately in accordance with the predetermined temperature profile.
A process for producing a predetermined temperature profile for a circuit board transported through at least three heat zones, comprising the steps of:
A process for producing a predetermined temperature profile for a circuit board transported through at least three heat zones, comprising the steps of:
A process for producing a predetermined temperature profile for a circuit board transported through at least two heat zones, comprising the steps of:
Dependencies are inferred from the claim text.