A robotic device for working on a surface includes a body including: a tool for working on the surface; a controller moving the body along the surface; a first set of at least two rotors mounted to the body and generating thrust in a first direction towards the surface; and a second set of at least two rotors mounted to the body and generating thrust in a second direction away from the surface. A sensor measures a distance between the body and the surface, and a computer adjusts the first set of rotors and the second set of rotors in response to the sensor to place the body in position to work on the surface. In particular, the first set of rotors and the second set of rotors generate a net force on the body to it in non-contact position to work on the surface.

A vehicle heater includes a heater housing (12′), through which heating air to be heated can flow, with a heating air inlet area and with a heating air outlet area. A burner unit is arranged in the heater housing. A combustion air blower (46′) is arranged in the heater housing for delivering combustion air to the burner unit. A heat exchanger unit is arranged in the heater housing (12′). Heating air flowing through the heater housing (12′) can flow around the heat exchanger unit. A combustion air intake muffler (76) is arranged essentially in the heater housing (12′). A muffler housing (78) made in one piece with the heater housing (12′) is associated with the combustion air blower (46′).

An air cleaner includes a fan that is configured to suck air in an axial direction and discharge air between the axial direction and a radial direction. The air cleaner further includes a fan motor that is configured to rotate the fan. The air cleaner further includes an air guide unit that includes a cylindrical outer wall and an inner wall that is located in a center portion of the outer wall and that defines a space that is configured to receive the fan motor. The air guide unit defines an annular air flow path that is configured to receive air discharged by the fan and that is defined by an inner circumferential surface of the outer wall and an outer circumferential surface of the inner wall. The air guide unit further includes a plurality of guide ribs. The air guide unit further includes a plurality of flow guide protrusions.

The present invention discloses fan system, which includes a volute having a front cover, a rear cover and an annular wall connected between the front cover and the rear cover: an impeller disposed inside the volute, and a motor; the front cover has an air inlet facing downward in the state when the fan system is mounted; the motor includes a motor body and an edge; the edge is connected to the rear cover at the side of the rear cover facing the air inlet. The present invention further discloses a range hood equipped with the fan system and a mounting method for the flow guide device.

A method for determining the positions of a number of fans (V.sub.n,m) for generating an air flow in a preferably enclosed space. The fans (V.sub.n,m) have an acceleration sensor to determine their position. The fans (V.sub.n,m) are arranged in rows (R.sub.1, R.sub.2, . . . , R.sub.n) and columns (S.sub.1, S.sub.2, . . . , S.sub.m). At least the position (i, j) of one fan (V.sub.i,j) is known.

A parallel double fan system, includes two fan systems disposed in parallel; wherein each fan system includes a volute having a front cover, a rear cover and an annular wall; the annular wall has a volute tongue; the rear cover has a first air outlet ocated above the corresponding volute tongue, two first air outlets in the two fan systems are communicated with each other. A range hood equipped with the parallel double fan system is also disclosed.

A tower fan is provided that includes a fan body having a double cross fan blower centered in the body of the fan with a motor positioned between the fan blowers in the center of the fan body. The tower fan is capable of being oriented in both the horizontal and vertical directions. The fan body may further include first and second ends and at least two supports. At least a first support is coupled to the first end of the fan body and a second support is removably coupled to the least second end of the fan body. The first and second ends of the fan body each have a groove for each receiving at least one of the at least two support members where each groove extends entirely around the fan body. The at least two supports may both be removably coupled to the fan body or one of the at least two supports may be permanently coupled to the first end of the fan body.

A magnetically attracted fan set comprises N+1 fans, the N≥1, and each of the N+1 fans has a fan frame and an airflow generating component disposed on the fan frame. Any two adjacent fans of the N+1 fans respectively have a joint surface, each of the joint surfaces has at least one fixing member capable of forming magnetic attraction, when the joint surface is close to the other joint surface at a distance sufficient for the two fixing members on the two joint surfaces to form magnetic attraction, two of the N+1 fans are joined together. Accordingly, the invention is capable of directly and quickly joining the N+1 fans without requiring complicated assembly gestures or other external components.

Disclosed is a fan. The fan includes a support; a first motor installed on the support, the first motor having a first rotation shaft; a first blade installed on the first rotation shaft; a second motor installed on the support, the second motor having a second rotation shaft and being coaxial with the first motor; a second blade installed on the second rotation shaft, a tilt direction of the second blade being opposite to a tilt direction of the first blade; and an electric control board electrically connected to the first motor and the second motor and configured to control a relative rotation of the first motor and the second motor.

A treadmill may include two separate left and right belts rotating around two sets of rollers, four legs having an adjustable height via air suspension to customize an inclination of the treadmill, a thermoelectric assembly, a fragrance assembly having a rotating fragrance cartridge to emit various smells toward a user of the treadmill, a display on which exercise programs are played, and an attachment module having a dispensing tray on which treats are dispensed. A handle of the treadmill may have a sensor to sense a height and front-rear position, and a belt divider provided between the left and right belts may have position or proximity sensors to sense a left-right position. An inclination of the treadmill may be automatically adjusted according to positions detected by the sensors, and the fragrance assembly, attachment module, and inclination may be automatically operated in accordance with an exercise program played on the display.