Hand held appliance

Abstract

A hair care appliance that includes a body, a fluid flow path extending from a fluid inlet into the appliance to a fluid outlet from the body, a heater for heating fluid in the fluid flow path, a pre-heater located upstream of the heater and a thermal safety device positioned between the pre-heater and the heater. The pre-heater may include a resistive element. The pre-heater may be electrically connected to the heater via a heater circuit. The thermal safety device may be electrically connected to the heater via the heater circuit. When the appliance is activated, fluid may flow from the fluid inlet through the pre-heater, past the thermal safety device, through the heater and on to the fluid outlet. The thermal safety device may extend orthogonal to a longitudinal axis A-A of the body.

Description

REFERENCE TO RELATED APPLICATIONS[0001]This application claims the priority of United Kingdom Application No. 1521694.8, filed Dec. 9, 2015, the entire contents of which are incorporated herein by reference.FIELD OF THE INVENTION[0002]This invention relates to a handheld appliance and in particular a hair care appliance such as a hairdryer.BACKGROUND OF THE INVENTION[0003]Generally, a motor and fan are provided which draw fluid into a body; the fluid may be heated prior to exiting the body. The motor is susceptible to damage from foreign objects such as dirt or hair so conventionally a filter is provided at the fluid inlet to the blower. The fan and heater require power in order to function and this is provided via internal wiring from either a mains power cable or batteries attached to the appliance.[0004]Conventional hairdryers have control buttons which can change one or more of the flow rate and the temperature of the fluid that exits the hairdryer. However, if the flow rate is ...

AI Technical Summary

Benefits of technology

The invention provides a solution that does not increase the size of a product or require modifications to the heater element windings to accommodate a thermal safety device. The thermal safety device is positioned perpendicular to the main flow path of the fluid, maximizing its exposure to the fluid and ensuring it is effectively pre-heated. This solution improves the effectiveness of the thermal safety device.

Problems solved by technology

The motor is susceptible to damage from foreign objects such as dirt or hair so conventionally a filter is provided at the fluid inlet to the blower.

However, if the flow rate is increased there is usually a drop in the temperature of the fluid that exits the hairdryer that can be perceived by the user.

There can be an electrical failure of some sort; alternatively dust and dirt can be pulled into the heater element and if this builds up it can burn and cause an increase in the temperature of the fluid exiting the hairdryer.

Obviously, thermal protection is provided in the form of thermal cut outs such as thermal fuses or bi-metallic strips to prevent an excessive increase in temperature but such protection renders the hairdryer inoperable either temporarily or permanently.

One problem with this is that it causes the length of the product to be increased in order to house the safety device.

Other solutions have been to either place the safety device within the windings of the heater, as is disclosed in Italian Patent Number 255589 however this adds to the complexity of manufacture of the heater or, to position the bi-metallic strip radially external to the heater however, this requires the diameter of the housing to be increased to accommodate the safety device.

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