Abstract: A potential measuring device which measures a charged object in a non-contact manner with a sensor may include a first shutter having a first shutter part, which is provided with a first opening which can be positioned at a position opposing the sensor, and leaf spring parts extending from both ends thereof; a second shutter having a second shutter part, which is provided with a second opening which can be positioned at a position opposing the sensor and the first opening, and leaf spring parts extending from both ends thereof; a coil provided so that a direction along a center axis opposes portions of the leaf spring parts; and a magnet provided on each of regions opposing both end sides of the coil in the leaf spring parts extending from the both ends of each of the first shutter part and the second shutter part.

Abstract: There is provided a potential measuring device of non-contact type which can improve measurement sensitivity. A potential measuring device which measures a charged object in a non-contact manner with a sensor includes: a first shutter and a second shutter each having a shutter part provided with an opening and a leaf spring part; a magnet attached to the leaf spring part of each of the first shutter and the second shutter; a yoke on which a coil is disposed, the coil applying an alternating magnetic field to the magnet of each of the first shutter and the second shutter to cause the shutter part to reciprocate via the leaf spring part; and a natural frequency adjusting means for adjusting a natural frequency of at least one of a first shutter system including the first shutter and the magnet and a second shutter system including the second shutter and the magnet.

Abstract: An object of the present invention is to remove foreign matter such as liquid droplets from air with high efficiency using a filter. This filter is used to purify air by removing foreign matter such as liquid droplets and dust from the air. A separation unit is formed with a port block and a separation cylinder, and the port block is formed with a primary port and a secondary port. A collection container is attached to the separation unit, and liquid droplets exhausted from an exhaust port formed at a lower end portion of a separation unit fall down into a collection container. A conical portion of the separation unit is formed with a communication hole through which the separation chamber and the storage chamber communicate with each other, whereby the separation chamber and the storage chamber become equal in pressure to each other.