Abstract: A cooling system for a heat source, such as a laser system, that includes a mixing valve mixing a cooling fluid from a hot line and a cold line and providing the mixed cooling fluid to the heat source, and a bladder tank having a bladder and including a hot side on one side of the bladder in fluid communication with the hot line and a cold side on an opposite side of the bladder in fluid communication with the cold line. A heat exchanger cools the cooling fluid flowing through the cold line. The cooling system is configured so that when the heat source is on and generating heat, cold cooling fluid from the cold side of the bladder tank is provided to the mixing valve and when the heat source is off and not generating heat, cold cooling fluid from the cold line fills the cold side of the bladder tank.

Abstract: An improved electric motor (34) includes a plurality of resiliently deflectable members (144, 146) which are disposed between a base (108) and a stator (100) to reduce transmission of vibration between the base and the stator. The resiliently deflectable members (144, 146) may be tubular spring pins which are disposed between the stator (100) and the base (108). Each of the tubular spring pins (144, 146) may have a cylindrical side wall (186) which defines a slot (184). During operation of the electric motor (34), vibration induced in the stator (100) causes the side walls (186) of the spring pins (144, 146) to resiliently deflect to attenuate the vibration. The stator (100) may be mounted on a tubular section (108) of the base. The spring pins (144, 146) may be disposed between the stator (100) and the tubular section (108) of the base. The tubular spring pins (144a) may be formed by rolled up sheet members (200).

Abstract: An apparatus (30) for use in pumping hydraulic fluid includes a pump unit (32) which is driven by an electric motor (34). The electric motor (34) is mounted on a tubular stem (108) which extends axially outward from a manifold plate (44). A stator (100) of the electric motor (34) is fixedly connected with the tubular stem (108). A rotor (112) of the electric motor (34) encloses the stator (100). A hydraulic muffler (50) attenuates noise produced by the gear pump unit (32). The hydraulic muffler (50) includes a channel (58) which extends into the manifold plate (44) from a major side surface (63) of the manifold plate. To increase the ability of the hydraulic muffler (50) to attenuate noise, one or two compliant elements (152 or 166 and 168) are connected with the channel (58).

Abstract: An apparatus comprises a reservoir (14) containing hydraulic fluid (68), a gear pump (16) with a suction hole (74), and a hydraulic muffler (18). The gear pump (16) has gears (78) with meshing teeth (80) that convey a flow of hydraulic fluid (68) from the reservoir (14) into the pump (16) through the suction hole (74). The muffler (18) attenuates noise by damping flow rate fluctuations that are caused by the meshing gear teeth (80). The muffler (18) includes a compliant element (92) and a fluid inertia structure (90) interposed between the suction hole (74) and the fluid (68) in the reservoir (14). The inertia structure (90) responds to the flow rate fluctuations by directing corresponding hydraulic pressure fluctuations to deflect the compliant element (92). As a result, noise is attenuated upon deflection of the compliant element (92).

Abstract: There is provided an optically pumped laser apparatus 10 which includes a heat conductive assembly 14 which is affixed to a solidstate yag laser crystal medium for generating a laser beam 49 within the laser crystal medium 12. The heat conductive assembly 14 comprises a heat diffusing element 32 which serves to diffuse the heat that is generated through the cooling surfaces 24 and 26. It includes a heat discharging structure 33 for removing the heat from the system. The efficiency of the laser system is improved by the geometry of pumping the crystal laser medium along the paths shown by the arrow 40 and to directing heat removed by the heat conductive assembly along the arrows 42, which paths are normal to one another and which provide an effective geometry that minimizes temperature variations within the laser crystal 12 to provide a low value for the OPD of the system.

Abstract: A compact diode pumped solid state slab laser gain module 20 is described. The laser gain module comprises a ceramic housing 22, a laser gain medium 24 disposed in the laser cavity 22, and an optical pumping source. The housing is preferably composed of alumina which provides thermal and structural stability at high temperatures to maintain beam alignment and eliminates parasitic oscillations. The laser gain medium is preferably a slab of crystalline Nd:YAG. Diode laser arrays 48, 50 are provided to pump at least one side face 30, 32 of the laser gain medium. Each diode laser array 48, 50 is mounted to a manifold 40, 42 preferably formed of a plastic, non-contaminating material. The laser gain module comprises a simplified cooling distribution for cooling the laser gain medium to produce a substantially uniform temperature distribution between its top and bottom faces, and for cooling the diode laser arrays.

Abstract: A solid-state laser architecture producing a beam of extremely high quality and brightness, including a master oscillator operating in conjunction with a zig-zag amplifier, an image relaying telescope and a phase conjugation cell. One embodiment of the laser architecture compensates for birefringence that is thermally induced in the amplifier, but injects linearly polarized light into the phase conjugation cell. Another embodiment injects circularly polarized light into the phase conjugation cell and includes optical components that eliminate birefringence effects arising in a first pass through the amplifier. Optional features permit the use of a frequency doubler assembly to provide output at twice optical frequencies, and an electro-optical switch or Faraday rotator to effect polarization angle rotation if the amplifier material can only be operated at one polarization.

Abstract: A valve (10) for controlling flow of hydraulic fluid. The valve (10) has first and second valve members (80, 82) which have a plurality of lands and grooves. The valve members (80, 82) are relatively movable from a neutral position to a displaced position in which surface segments (202, 226, 208, 218) of respective pairs of lands overlap to form flow gaps (232, 234) for restricting flow of fluid between respective pairs of grooves. At least one (234) of the flow gaps is divergent by having a cross-sectional flow area which increases along a direction of fluid flow and at least one (232) of the flow gaps is convergent by having a cross-sectional flow area which decreases along a direction of fluid flow. The flow gaps (232, 234) have minimum cross-sectional flow areas (A, B) defined by the surface segments.

Abstract: A solid-state laser architecture producing a beam of extremely high quality and brightness, including a master oscillator operating in conjunction with a zig-zag amplifier, an image relaying telescope and a phase conjugation cell. One embodiment of the laser architecture compensates for birefringence that is thermally induced in the amplifier, but injects linearly polarized light into the phase conjugation cell. Another embodiment injects circularly polarized light into the phase conjugation cell and includes optical components that eliminate birefringence effects arising in a first pass through the amplifier. Optional features permit the use of a frequency doubler assembly to provide output at twice optical frequencies, and an electro-optical switch or Faraday rotator to effect polarization angle rotation if the amplifier material can only be operated at one polarization.

Abstract: A cryogenic heat exchanger, such as a pulse tube cryogenic heat exchanger, is provided wherein the chilled heat transfer connection point can be conveniently disposed at an "apex." The heat exchanger has a bridging chamber with a first opening and a second opening. Disposed within the bridging chamber is a plurality of fins disposed longitudinally between the first opening and the second opening so as to partition the bridging chamber into a plurality of parallel longitudinal channels of equal cross-section. The first opening and the second opening are disposed at an angle to one another, so that a heat transfer gas flowing through the heat exchanger, changes direction within the bridging chamber.

Abstract: A valve for controlling flow of hydraulic fluid. The valve includes first and second relatively movable valve members (60 and 62). The valve members (60 and 62) include cooperating surfaces (112, 142, 144) which define first and second orifices for metering fluid from a pressurized fluid source (44) toward first and second locations (22 and 24) in a fluid utilization device (12). The valve members (60 and 62) have a displaced position in which the first orifice is increased in size and the second orifice is decreased in size. The increased size of the first orifice reduces a pressure drop across the first orifice. The decreased size of the second orifices increases a pressure drop across the second orifice. The valve members (60 and 62) include means (114 and 146) for increasing a pressure on a downstream side of the second orifice to reduce the pressure drop for controlling valve noise.

Abstract: A valve for controlling flow of hydraulic fluid. The valve includes a valve sleeve and a valve core. The core is disposed within the sleeve. The core and sleeve are relatively rotatable. Each of said core and sleeve has an axially extending land and an axially extending groove. The core and sleeve have relative rotational positions such that the lands overlap to define a flow gap for flow of hydraulic fluid from the groove in the sleeve to the groove in the core. The flow gap has a minimum cross-sectional flow area adjacent to the groove in the core. The minimum cross-sectional flow area constantly varies as the core and sleeve relatively rotate. The land on the sleeve has a notch immediately adjacent to, and downstream of the minimum cross-sectional flow area which provides an abrupt increase in cross-sectional flow area for suppressing valve noise due to cavitation.

Abstract: A rotating disk reactor for producing singlet delta oxygen is disclosed. The reactor includes a plurality of closely spaced coaxial disks partially immersed in a pool of liquid basic hydrogen peroxide (BHP) inside a reactor vessel. A thin film of BHP is picked up and carried on the rotating disks. Chlorine gas, diluted with helium, is flowed into the reactor vessel to pass between the disks and react with the BHP to produce singlet delta oxygen. The singlet delta oxygen flows out of the reactor through a liquid separator to remove liquids and then through an impurity cold trap to remove by condensation gaseous H.sub.2 O.sub.2 and H.sub.2 O.

Abstract: A valve for controlling flow of hydraulic fluid. The valve includes a valve sleeve and a valve core. The core is disposed within the sleeve. The core and sleeve are relatively rotatable. The sleeve has grooves connected to a utilization device. The core has grooves connected to a fluid supply and reservoir. The core and sleeve have lands which radially overlap during relative rotation of said core and sleeve to restrict fluid flow from a portion of the grooves in the sleeve to the grooves in the core connected to the reservoir. The lands on the sleeve have chamfered end faces with tapered segments.