SEMICLOSED CYCLE GAS LASER SYSTEM

• Main Authors: GORKEN MELIKIAN, FRANK R. BIANCARDI
• Format: Patent
• Language: English
• Published: 07.03.1972
• Subjects: BASIC ELECTRIC ELEMENTS; DEVICES USING STIMULATED EMISSION; ELECTRICITY

A flowing gas laser system of the mixing type removes lasing gas from the laser effluent so as to recycle the remaining gas, such as a mixture of energizing gas and relaxant gas. Fresh lasing gas is introduced into the system from a pressurized source thereof. Typically, carbon dioxide is removed from the laser effluent so as to permit reuse of a mixture of helium and nitrogen, by means of a lithium oxide or lithium hydroxide solid absorbent bed which is cooled by expanded CO2 from the liquefied source. In one embodiment, the liquid CO2 also precools the main gas flow prior to entrance into the CO2 adsorber. The warmed CO2, with or without additional external heat supplied thereto, is passed through an expander, which operates a turbine to drive a compressor used for creating flow through the system. The CO2 which leaves the expander at temperatures of about 0 DEG F. is then divided into two streams. One stream may be used to precool the laser effluent gases prior to reaching the compressor inlet as well as cool the laser chamber, while the other stream is used directly in the laser chamber. An excess of CO2 may be flowed through all of the above-described processes by venting some of it to ambient, and using only part of it as the lasing gas, or a part of the CO2 may be passed directly from the liquefied source into the laser chamber. A second embodiment employs a prime mover to drive the flow-inducing compressor, the liquid CO2 being expanded and passed directly into the laser chamber at a very low temperature or serving to remove heat from the CO2 adsorber, prior to its use as a lasing gas. External coolants are provided so as to cool the adsorbent or pre- and post- cool the laser effluent as it moves through a compressor, thereby maintaining the size of the compressor and the power requirements thereof quite small. Electrical power may be generated on the compressor drive shaft in either embodiment. The latter embodiment may employ readily available electrical power to run an electric excitation power supply, and even a small electric motor to drive the compressor.