4539 results about "Gas bubble" patented technology

The present invention relates to a method for gas-solid contacting in a bubbling fluidized bed reactor by:(a) introducing into a reactor with bed length to bed diameter ratio below about 5.0, a primary gas consisting essentially of reactant(s) of the reaction to be carried out in the bed of solid particles through a primary gas distributor located at the reactor bottom at a superficial gas velocity Up, which is very close or equivalent to the minimum fluidization velocity Umf, required for achieving the incipient fluidization of the solid particles in the bed to obtain an emulsion phase consisting essentially of the solid particles and the primary gas with little or no formation of gas bubbles to achieve incipient fluidization or liquid-like behavior of fluidizable solid particles;(b) forming gas bubbles in the incipiently fluidized bed by introducing through a secondary gas distributor located immediately above the primary gas distributor a secondary gas, selected from one of the reactants which is used in excess of that required for the reaction stoichiometry, steam, an inert or a mixture of two or more thereof at a superficial gas velocity, Us, which is related to the superficial velocity of the primary gas such that a ratio of the superficial velocity of the secondary gas to the superficial velocity of the primary gas Us / Up, is in the range from about 0.5 to about 10.0, preferably from about 1 to about 5.

Techniques for generating a stable, force-resisting positive or negative representation of a shape. A state-changeable mixture includes uniform, generally ordered, closely-spaced solid bodies and a liquid carrier medium, with the liquid filling any voids or interstices between the bodies and excluding air or gas bubbles from the mixture. Within the mixture, the solid bodies can be caused to transition from a near-liquid or fluent condition of mobility to a stable, force-resisting condition. To create mobility, a small excess quantity or transition liquid is introduced to create a fluent condition by providing a slight clearance between the bodies which permits the gently-forced introduction of at least two simultaneous slip planes between ordered bulk masses of the bodies at any point in the mixture. Transition to the stable condition is caused by extraction of the transition liquid, removing the clearance between bodies and causing them to make stable, consolidated contact.

A system and method are disclosed for monitoring and controlling a positive displacement pump using readings obtained from a plurality of pressure sensors. The pressure sensors may be mounted at the suction, discharge and interstage regions of the pump. Signals from the pressure sensors are compared to obtain a ratio that is used to predict whether a cavitation condition exists within the pump. The ratio can be compared to user provided limits to change an operating characteristic of the pump to reduce predicted cavitation. The pump may be stopped, or pump speed changed, when the ratio is less than a predetermined value. In some embodiments, historical information regarding the ratio may be used to obtain standard deviation information which may then be used to predict whether gas bubbles are passing through the pump. Other embodiments are described and claimed.

A system that breaks calcium in a liquid includes a catheter including first and second electrodes arranged to receive there-across a high electrical voltage at an initial low current. The high electrical voltage causes an electrical arc to form across the electrodes creating a gas bubble within the liquid, a high current to flow through the electrodes, and a mechanical shock wave. A power source provides the electrodes with the high electrical voltage at the initial current and terminates the high electrical voltage in response to the high current flow through the electrodes.

A method and apparatus for removing fouling materials from the surface of a plurality of porous membranes (9) arranged in a membrane module (4) by providing, from within the module, by means (10) other than gas passing through the pores of said membranes, gas bubbles in a uniform distribution relative to the porous membrane array such that the bubbles move past the surfaces of the membranes (9) to dislodge fouling materials therefrom. The membranes (9) are arranged in close proximity to one another and mounted to prevent excessive movement therebetween. The bubbles also produce vibration and rubbing together of the membranes to further assist removal of fouling materials.

A system for removing gas bubbles from blood during circulatory assist procedures. An active filter apparatus forces the bubbles to the center of the system where they are removed from the blood before the blood exits the filter.

A method and apparatus for cleaning a membrane module, the membrane module having a plurality of porous membranes, the membranes being arranged in close proximity to one another and mounted to prevent excessive movement therebetween and means for providing, from within the module, by means other than gas passing through the pores of the membranes, gas bubbles entrained in a liquid flow such that, in use, the liquid and bubbles entrained therein move past the surfaces of the membranes to dislodge fouling materials therefrom, the gas bubbles being entrained in the liquid by flowing the liquid past a source of gas to draw the gas into the liquid flow. The gas bubbles are preferably entrained into the liquid using a venturi type device. The membranes are preferably partitioned into discrete groups to assist cleaning while maintaining high packing density.