FIELD OF THE INVENTION

The invention relates to a hair dryer.

BACKGROUND OF THE INVENTION

A conventional hair dryer blows heated air out axially from the dryer body onto the user. Usually, some heated air is not reaching the hair and get wasted. Some heated air is over-heating the user’s scalp or facial skin. The rest of the heated air although is aiming at the hair, but it is blowing hair away from the user, tangling the hair and at the same time reducing the contacting time between the heated air and the hair, thus has a very low drying efficiency. Usually it requires the user to use another hand to control the hair to improve the drying efficiency and to detangle the hair at the same time.

US2019110571A1 discloses a hair dryer that includes a body provided in a cylindrical shape having an annular sectional surface, configured to form an air flow path, and provided with one or more air inlets and an air outlet; a blower fan provided between the air inlets and the air outlet, and configured to be rotated to thus introduce external air into the body and blow the external air; and a heating coil provided between the blower fan and the air outlet, and configured to heat the external air; wherein air outside the air flow path is introduced into the air flow path and blown to the user along with the air being blown via the air outlet by means of a difference in air pressure between the inside region of the air flow path and a region outside the air flow path.

WO2019027211A1 discloses a hair dryer having the function of a curling iron such that the same is capable of styling hair while drying the same. More particularly, the hair dryer is structured such that a handle portion and a body portion are connected so as to intersect with each other. The handle portion comprises: a first housing having an air inlet formed through one side thereof and having a hollow first channel formed therein such that air flows along the same; and a blowing fan installed in the first housing so as to forcibly introduce outer air from the air inlet, thereby generating a flow of air along the first channel. The body portion comprises: a second housing having the shape of a hollow barrel, the second housing being connected so as to intersect with the other end portion of the first housing such that the same communicates with the first channel; a third housing coupled inside the second housing so as to constitute a double-barrel structure together with the second housing, the exterior of the third housing being spaced apart from the second housing by a predetermined interval, thereby forming a second channel, the third housing having a hollow third channel formed therein and having an opening provided through one side of the third channel as an air outlet; and multiple first discharge holes penetrating the third housing such that the second channel and the third channel communicate with each other, the inner wall surface of each first discharge hole having an inclination toward the air outlet. The air flowing through the third channel has a temperature sufficient to dry the hair by the third housing, which is a heating plate. A heat generating coil for heating the air flowing through the first channel may further be installed in the first housing to further improve the efficiency of the dry process.

SUMMARY OF THE INVENTION

It is, inter alia, an object of the invention to provide an improved hair dryer.

The invention is defined by the independent claims. Advantageous embodiments are defined in the dependent claims.

One aspect of the invention provides a hair dryer comprising a fan, an outer shell, an inner shell around a hollow area, the inner shell having a hair inlet configured for allowing hair to enter the hollow area at a first end of the hollow area, an air outlet at a second end of the hollow area opposite to the first end, and a plurality of slots for directing the air flow from between the outer shell and the inner shell into the hollow area into a direction from the hair inlet to the air outlet. A heater between the outer shell and the inner shell heats part of the air before that part of the air enters the hollow area. In accordance with the invention, a first slot of the plurality of slots is positioned near the hair inlet and configured for generating a low pressure area at the hair inlet for sucking the hair into the hollow area, and the heated air enters the hollow area via a further slot of the plurality of slots, the further slot being positioned between the hair inlet and the air outlet to heat the hair that has been sucked into the hollow area.

It matters for the air flow through the hollow area whether a slot is close to the hair inlet (as in this aspect of the invention) or close to the air outlet (as in e.g. US2019110571A1), because if the slot is close to the air outlet, it can draw air from through the hollow area and air from outside the hair dryer to flow with the air from the slot. As it is easier for the outside air to flow with the air blown from the slot, only a relatively small part of the air drawn by the air from the slot will be air flowing thru the hollow area. In contrast, as air blown from a slot near the hair inlet will not cause any outside air to flow along the hair dryer, a slot near the inlet is able to create a much lower pressure at the hair inlet that is much better able to suck hair into the hair inlet than a slot near the air outlet.

Preferably, the first part of the air flow does not pass the heater. Advantageously, the heater includes a heating wire around the inner shell. Advantageously, a handle is positioned in parallel (but 180° turned) to a central axis of the outer shell.

These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 shows an embodiment of a hair dryer according to the invention. DESCRIPTION OF EMBODIMENTS

The embodiment of a hair dryer shown in Fig. 1 comprises a hollow cylindrical handle Hd with an air inlet AI near the base of the handle Hd, a body B that has an outer cylindrical shell OS and an inner cylindrical shell IS, with the ends of the two cylindrical shells OS, IS connected with closed surfaces, a hollow bridge connecting the hollow handle Hd to the hollow body B, and radial slots S 1, S2, S3 on the inner shell IS of the body as air outlet to allow air to enter a hollow area HA enclosed by the inner shell IS. The motor and fan assembly F is residing inside the hollow handle Hd, sucking ambient air A through the air inlet AI into the hollow handle Hd, pushing the air A through the hollow bridge into a hollow space between the outer and inner shells OS, IS of the body, and air A leaves the body B from the radial slots SI, S2, S3 on the inner cylindrical shell IS. Air A is heated by the heater Ht residing between the inner and outer shell of the body. The slots SI, S2, S3 on the inner shell IS are designed to direct air flow to one direction only parallel to the axis of the cylindrical surface of the body B, allowing air to blow out from an air outlet AO of the dryer body B. In Fig. 1, hollow arrows indicate the air flow path. The radial slots SI, S2, S3 are designed in a way to direct air flow to one direction along the center hollow area HA, allowing hair H to be inserted into the hollow area HA from a low pressure hair inlet HI (top entrance in Fig. 1). Once hair H is inserted, it can be dried by the heated air inside the hollow area HA and towards the outlet AO of the dryer.

The heater Ht is assembled between the inner shell IS and the outer shell OS of the dryer’s body B. Because of the constant air flow inside the dryer, a conventional nichrome wire (coil heater, made from an alloy of nickel and chromium) can advantageously be used as the heater Ht for this dryer. Small mica plates can be secured on the inner surface of the inner shell and be used to support the nichrome coil heater Ht.

According to an embodiment of the invention, a first slot S 1 of the plurality of slots S 1 -S3 allows a first part of the air flow A to enter the hollow area HA that has not passed the heater Ht, while the heated air from the heater Ht enters the hollow area HA via further slots S2, S3. As the heater Ht restricts (i.e. poses a hindrance for) the air flow A from the fan F, the first slot SI allows a relatively large portion of fast moving air from the fan F to enter the hollow area close to the hair inlet HI, thereby better generating a low pressure area at the hair inlet HI for sucking the hair H into the hollow area HA.

The motor controller board or any required PCBA can be placed at the air inlet area inside the handle Hd or inside the hollow bridge, where it can be advantageously cooled by the air flow.

The fan F can be powered by means of a mains voltage, or by means of a battery that is preferably placed in the handle Hd where it can be cooled by the air flow.

While in Fig. 1, the handle Hd is shown parallel to the body B, which is believed to be ergonomically optimal, the handle Hd may be positioned perpendicular to the body B. While in Fig. 1, the inner and outer shells IS, OS are cylindrical, their cross-sections need not be circular and may have another shape, e.g. rectangular.

The new hollow hair dryer design allowing heated air flowing along the inner shell’s outer surface and blowing the heated air out from one side, provides several benefits compared to a conventional hair dryer. First, hair H can be inserted into the hollow area HA in the center of the dryer’s body B, and all the heated air can reach every strand of the hair, maximizing drying efficiency. Also, hair H can be dried in an isolated area, and heated air will not blow directly onto the scalp or the facial skin. A user will not need to use the other hand to detangle or hold the hair while drying because the air will flow along the hollow area HA and directed out axially, thus hair movement will be controlled in the hollow area HA.

This standalone dryer gives a similar air flow performance as a conventional hair dryer as all the air flow is directed to exit towards one side (towards the bottom in Fig. 1) of the dryer, and the temperature can be equivalent to a normal hair dryer as well as there is enough room for a long heater coil just like in a conventional hair dryer. The fan motor may be a high speed BLDC motor. Therefore, it would result in similar drying rate when used as a conventional hair dryer. This design also allows the user to put hair inside the hollow area HA for focus drying. One advantage of putting the heater H inside the hollow space between the inner and outer shells IS, OS compared to at the motor outlet in the handle Hd is the higher heating/flow restriction efficiency. To achieve a certain air stream temperature, a certain length of the heater coil is preferred. When putting the heater coils in a tight space (e.g. in the handle Hd at the fan motor outlet), it will significantly restrict the air flow, and thus decrease air flow performance. And when this weakened air flow exits the dryer, although using small slots at the air outlet AO can increase the air speed and pressure, it will still feel significantly weaker than if the heater Ht is spread out through the wind path in a bigger area. If, in accordance with embodiments of the invention, the heating coil Ht is spread out and put in a less restrictive area (i.e. in the body B between the inner and outer shells IS, OS), the air flow can be heated in a less restrictive way, and at the end when the flow is focused again at the air outlet AO, the air speed and pressure can be greatly increased and give the dryer a powerful feeling.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps other than those listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. For example, where the claims mention “a slot”, an embodiment may have one or more slots, and the notion slot covers all forms of openings directing the air flow A from between the outer shell OS and the inner shell IS into the hollow area HA. Measures recited in mutually different dependent claims may advantageously be used in combination.