| 摘要 |
PURPOSE:To prevent destruction of a pressure detection element due to freezing of water even when water enters a pressure lead system, by arranging an internally hollow body along a lead path for leading a pressure to a pressure detection element to be brought into contact with a liquid filler in the lead path. CONSTITUTION:In the normal operation, pressure in an intake pipe transmitted through a rubber hose 15 propagates through a silicon oil 14 filled into a pressure introduction pipe 10, a pipe 8 and lead holes 2a and 3a and is transmitted to a diaphragm portion of a pressure detection element 1 to be detected. When water flows in and accumulates to the extent of covering the end face of the oil 14 to be frozen causing an expansion in the volume, a stress transmits to the oil 14 due to the expansion. But a hollow body 13 which is so lower in the rigidity than a part composing the pressure detection element 1, the pipe 8 and the like and so hollow thereinside that is reversibly deformable by a stress smaller than the destruction stress of the element 1 or such a stress as causing a permanent deformation is deformed and compressed under a stress due to the expansion to absorb the stress corresponding to the volumetric expansion due to the freezing. This can prevent the destruction of the element 1 due to the freezing of water. |
