Abstract: A thermal head comprises a head circuit board having a surface carrying a heating resistor line and at least one drive element for heating the resistor line. The drive element is enclosed in a resinous package. At least a surface portion of the resinous package is electrostatically conductive but electrically non-conductive to work as antistat. The antistatic surface portion or entirety of the resinous package may be made of electrically non-conductive matrix resin which contains a predetermined percentage of electrically conductive substance.

Abstract: A thermal printing head comprises a support member, a head circuit board supported on the support member, a connector board overlapped on the head circuit board, and a presser member for pressing the connector board against the head circuit board. The support member is flexible with a modulus of elasticity lying within a range of 1.times.10.sup.4 -5.times.10.sup.5 kg/mm.sup.2. The head circuit board carries a comb-like terminal portion arranged in a limited central portion which is substantially smaller in length than the head circuit board. The connector board also carries a comb-like terminal portion corresponding to the terminal portion of the head circuit board, and the length of the connector board is substantially smaller than that of the head circuit board.

Abstract: When a fluid is jetted from an orifice having a small diameter into an ample space having a much greater cross-sectional area than the orifice, as in the case of a refrigerant jetted from a restriction or orifice into a refrigerant pipe of a refrigeration system, jet noise of high frequency is generated in the region around the orifice. In order to suppress the generation of this jet noise, the present invention provides a silencer which includes a casing, an orifice of a small diameter arranged in the casing for jetting a refrigerant into the casing and an obstruction disposed in the casing at a position within a distance which is 5 times as large as the diameter of the orifice. The obstruction can have various forms such as bar-like form, disc-like form and so forth and can be made from various materials such as rubbers, plastics and metals. The obstruction disposed at such a position cause a change of pattern of the fluid flow to effectively suppress the generation of noise.

Abstract: A refrigeration system for use in air conditioner for automobiles. The refrigeration system has a pressure reducing device disposed between a condenser and an evaporator and adapted for permitting the refrigerant to make an adiabatic expansion therethrough. The pressure reducing device includes a flow restricting and resisting means such as an orifice and a flow resisting means disposed at the upstream side of the flow restricting and resisting means. The flow resisting means are adapted to impart a resistance to the flow of refrigerant and may be constituted by a capillary tube or a constant-pressure-differential valve. Because of the resistance imparted by the flow resisting means, the dryness factor of the refrigerant at the inlet to the flow restricting and resisting means is maintained between 0 and 0.1, so that the flow rate of the refrigerant is largely affected by the characteristic of the flow restricting and resisting means.