Pump and actuator

Abstract

A first surface of a porous medium is in contact with a first space. A second surface of the porous medium is in contact with a second space. The first space is in communication with the second space via the pores of the porous medium. Light in a wavelength range where the material of the porous medium exhibits light absorption properties is applied to the first surface of the porous medium from a light source, so that energy of the applied light can be efficiently absorbed into the porous medium from its first surface, and the first surface of the porous medium can be efficiently heated. As a result, a thermal transpiration flow can be efficiently generated in the porous medium, and a pressure difference can be efficiently produced between the first space and the second space.

Description

PRIORITY INFORMATION[0001]This application claims priorities to Japanese Patent Application Nos. 2012-185076, filed on Aug. 24, 2012, 2013-020589, filed on Feb. 5, 2013, and 2013-151827, filed on Jul. 22, 2013, which are incorporated herein by reference in their entireties.BACKGROUND[0002]1. Technical Field[0003]The present invention relates to a pump and an actuator that use a thermal transpiration flow.[0004]2. Related Art[0005]A thermal transpiration flow is the flow specific to a rarefied gas. When there is a wall having a temperature gradient in the rarefied gas, a flow in a direction along the wall is induced from a low-temperature part to a high-temperature part. This is referred to as the thermal transpiration flow. The rarefied gas is a gas which has such few impacts between gas molecules that an equilibrium state is not maintained in a given region. A specific example of the rarefied gas has a low pressure of about 1 Pa in a region of about 1 cm3, or has a pressure substan...

AI Technical Summary

Benefits of technology

The present invention provides a pump that uses a thermal transpiration flow to efficiently transfer a liquid. The pump includes a porous medium with light absorption properties and pores, and a heating unit that applies electromagnetic waves to the first surface of the medium to heat it. The heated surface comes into contact with a first space, while a second space is in communication with the first space through the pores. The diameter of the pores should be equal to or less than the length of the gas filling the spaces. The pump may also include a heat radiation device for heating the second surface of the medium.

Problems solved by technology

However, still air has low thermal conductivity (0.02 [W / (m·K)]), and the heat of the heater is not easily transmitted to the one side of the target porous membrane, so that the heating efficiency is low.

Therefore, according to Nonpatent Document 1, it is difficult to efficiently generate a thermal transpiration flow in the porous membrane.

The pump that uses the thermal transpiration flow can transfer a gas, but cannot transfer a liquid, in principle.

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