Abstract: A humidifying air purifier includes a body frame having an opened front and rear, a fan housing coupled to a rear end of the body frame and having a fan intake, a housing cover coupled to a rear end of the fan housing to accommodate an air blowing fan, and an air discharge port formed at an upper end of the fan housing and an upper end of the housing cover. A waterwheel motor is installed on a front surface of the fan housing and positioned outside the fan intake, a driving gear is coupled to the waterwheel motor, a door assembly is configured to be pushed into or drawn out from a front end of the body frame, a water tub is accommodated in a lower side of the door assembly, and a humidifying filter assembly is inserted into the water tub.

Abstract: A method for producing energy including: producing fuel gases from biomass raw material in a main receptacle unit (8), feeding produced fuel gas to a consumer unit (2,3), transferring energy from the consumer unit to at least one energy user (7). The method includes recovering heat and producing pressurized superheated steam, intermittently loading biomass raw material into at least one vessel (8?), being included in the main receptacle unit (8), pressurizing the loaded at least one vessel (8?) with pressurized superheated steam, passing pressurized superheated steam through the loaded and pressurized at least one vessel (8?), thereby contacting and heat treating said biomass raw material with the pressurized superheated steam for the production of said fuel gases, supplying produced fuel gases together with still superheated steam to the consumer unit (2,3). The invention also concerns a plant.

Abstract: A multi-stage aeration apparatus includes at least two vertically oriented aeration modules. Each aeration module defines a vertically elongated aeration chamber having a top inlet and a bottom outlet. The bottom outlet of each of the aeration modules feeds a fluid stream comprising liquid and gas into the top inlet of an underlying one of the aeration modules. Each aeration module has an aeration head connected to the top inlet, such that the fluid stream passing through the top inlet into the aeration chamber must pass through the aeration head, the aeration head aerating the liquid with the gas in the fluid stream.

Abstract: A fuel cell system includes a water vapor transfer unit and a fluid flow distribution feature, the water vapor transfer unit including a first plate having a plurality of first flow channels for receiving a flow of a first fluid therein, and a second plate having a plurality of second flow channels for receiving a flow of a second fluid therein. The fluid flow distribution feature is configured to control at least one of a volume of flow of the first fluid through the first flow channels and a volume of flow of the second fluid through the second flow channels, wherein at least one of a flow distribution of the first fluid across the first plate and a flow distribution of the second fluid across the second plate is varied.

Abstract: Various embodiments include two-stroke stratified engines and dual passage carburetors for use with gaseous fuel, such as hydrogen, methane, liquid petroleum gas, pure propane, and butane. A stratified air-head engine and low pressure fuel injected engines with fuel only tube is included.

Abstract: A gaseous fuel mixer for an internal combustion engine includes a mixer body and a mixer element supported in a mixer passage formed in the mixer body. The gaseous fuel mixer attaches to an intake manifold at a first end and receives intake air at a second end. A distal end of the mixer element accepts gaseous fuel from a manifold passage extending from a port positioned in the intake manifold. The gaseous fuel flows through the mixer element and then through a plurality of openings formed in an exposed proximate end of the mixer element. The gaseous fuel mixes with the intake air, and the mixture of intake air and gaseous fuel flows from the second end of the mixer body to the first end of the mixer body and then to the intake manifold.

Abstract: A gas mixture supplying method includes supplying plural kinds of gases through gas supply lines connected to a common pipeline and supplying a gas mixture of the plural kinds of gases from a gas outlet of the common pipeline into a region where the gas mixture is used through a gas mixture supply line. When a typical gas supplied in a gaseous state from a gas supply unit and a liquid source gas vaporized by heating a liquid source material supplied from a liquid source material supply unit by a vaporizing unit are supplied simultaneously, the liquid source gas is supplied from one of the gas supply lines provided at a position closer to the gas outlet than that for the typical gas, and the liquid source gas is supplied to a downstream side of a filter for removing particles in the typical gas.

Abstract: Collecting line for removing hot process gases conducted in process gas tubes from tubular reformers, wherein the collecting line has on the inside at least one insulation layer made of fire-resistant concrete or fire-resistant brick, and on the outside a wall made of a metallic outer tube, comprises a plurality of stubs via which the process gas tubes of the tubular furnace can be connected to the collecting line, wherein in the region of the stubs, the process gas tubes are at least in part conducted in guide tubes, and each gas outlet connected to the respective process gas tube projects into the collecting line, by means of which the process gas is introduced into the collecting line in correct functioning, and at least one gas outlet is constructed as a pipe bend.

Abstract: A gaseous fuel mixing device includes a body having an air/fuel passageway and a gaseous fuel passageway in fluid communication with the air/fuel passageway, a throttle valve pivotably coupled to the body and positioned in the air/fuel passageway, and an intake unit coupled to the body. The intake unit includes an inlet configured to be fluidly connected with a source of gaseous fuel, a first jet fluidly communicating the inlet and the gaseous fuel passageway, a second jet selectively fluidly communicating the inlet and the gaseous fuel passageway, and a selector valve operable to control a flow of gaseous fuel through the second jet.

Abstract: Stable and adjustable humidification of a gas are achieved by separating a gas stream into two streams and humidifying one of the gas streams. The desired level of humidification of the final product gas stream can be achieved by adjusting the relative flow rates of the two gas streams so that when they are combined to form a final product gas stream that has the appropriate level of humidity.

Abstract: A pressurized water tank having a head space includes a pump for recirculating the water through a nozzle disposed in the head space. The outflowing stream of water will entrain air and cause mixing of air entrained water with the remaining water in the tank. To enhance air entrainment and convey the air entrained water to a location well below the water level, the stream of water is injected into a vertical venturi tube. The entrained air will have an oxidizing effect upon organic matter and also cause circulation of the water within the tank. To enhance oxidation of organic and inorganic matter, a UV lamp may be located in the head space to convert oxygen molecules in the air into ozone molecules. Such ozone molecules would be entrained in the stream of water flowing out of the nozzle and into the tube and have a strong oxidizing effect upon organic and inorganic matter.

Abstract: Method and apparatus for treating contaminants on a site, especially a deep well site includes delivering a first stream of a first gas to a first port of a laminar microporous diffuser and delivering a second stream of a second gas to a second port of the laminar microporous diffuser to effect mixing of the first and second streams of gases within the laminar microporous diffuser.

Abstract: The invention relates to a method for creating transient cavitation comprising the steps of creating gas bubbles having a range of bubble sizes in a liquid, creating an acoustic field and subjecting the liquid to the acoustic field, characterized in that the range of bubble sizes and/or the characteristics of the acoustic field are selected to tune them to each other, thereby controlling transient cavitation in the selected range of bubble sizes. It also relates to an apparatus suitable for performing the method according to the invention.

Abstract: Method and apparatus for treating contaminants on a site, especially a deep well site includes delivering a first stream of a first gas to a first port of a laminar microporous diffuser and delivering a second stream of a second gas to a second port of the laminar microporous diffuser to effect mixing of the first and second streams of gases within the laminar microporous diffuser.

Abstract: A humidifier for fuel cells includes a housing with a heat-exchange plate formed therein, the plate defining first and second gas passages having gas inlets and outlets, respectively; a plurality of apertures formed on the plate; and a plurality of reservoirs fixed under the apertures and filled with a water absorbable and permeable stuffing material for trapping and storing water. The water permeable stuffing material may be disposed in the first gas passage. Cool, dry oxygen/air is channeled to the first gas passage and conveyed to an oxygen/air inlet of the fuel cell, and high-temperature, high-moisture exhaust gas discharged from the fuel cell is introduced to the second gas passage, such that water and heat of the exhaust gas in the second gas passage are recycled by the heat-exchange plate and conveyed to the first gas passage, thereby achieving the humidification effect and improving electricity-generating efficiency of the fuel cell.

Abstract: There is disclosed an internal combustion engine carburetor fuel/air circuit air bleed input control device having an air distribution block, at least one air input port and one or more air output ports connected with the air bleed inputs of one or more carburetors. A control valve is disposed between the air input and an air flow balance chamber to which the output ports are connected. Two valves and balance chambers can provide control for carburetors having two fuel/air circuits. Optionally, an input air tube may be provided so that the source of air for the air distribution block input or inputs may be located in selected locations, for example, in a carburetor air stream. Another option is to provide a remote control from, for example, the handlebars of a motorcycle.

Abstract: To reduce the level of oxygen concentration in the waste gases emitted by the stack of such installations, according to the invention, connecting means (15) connect the respective internal spaces of a chamber (13), for discharging an inert gas miscible with oxygen and of lower density than air, such as nitrogen, and of the stat (2); thus, this inert gas is mixed with at least the oxygen flowing through the stack and the mixture obtained is discharged with a velocity at least equal to approximately 7 m/s at the exit of the stack.

Abstract: To reduce the level of oxygen concentration in the waste gases emitted by the stack of such installations, according to the invention, connecting means (15) connect the respective internal spaces of a chamber (13), for discharging an inert gas miscible with oxygen and of lower density than air, such as nitrogen, and of the stack (2); thus, this inert gas is mixed with at least the oxygen flowing through the stack and the mixture obtained is discharged with a velocity at least equal to approximately 7 m/s at the exit of the stack.

Abstract: To reduce the level of oxygen concentration in the waste gases emitted by the stack of such installations, according to the invention, connecting means (15) connect the respective internal spaces of a chamber (13), for discharging an inert gas miscible with oxygen and of lower density than air, such as nitrogen, and of the stack (2); thus, this inert gas is mixed with at least the oxygen flowing through the stack and the mixture obtained is discharged with a velocity at least equal to approximately 7 m/s at the exit of the stack.

Abstract: A diaphragm carburetor is provided for an internal combustion engine that operates with scavenging air, especially a two-cycle engine in a manually-guided implement. The carburetor has an intake channel portion in which is disposed a butterfly valve that is rotatably held via a shaft and in the vicinity of which fuel-supplying channels open into the intake channel portion. The channels are supplied from a fuel-filled regulating chamber that is formed on a longitudinal side of the intake channel portion in the carburetor housing and is separated by a regulating diaphragm from a compensation chamber. The carburetor has at least one air channel that supplies additional combustion air and that has an air valve that is rotatably held via a shaft.

Abstract: A process for the production of synthesis gas for obtaining compounds such as ammonia or methanol, in which hydrocarbons and steam are reacted first in a primary reforming section (11) and then—together with oxygen—in a secondary reforming section (12), thus obtaining CO, CO2, H2 and possibly N2 which are then fed to a carbon monoxide conversion section (13, 14), is distinguished by the fact of reacting hydrocarbons, steam and oxygen in an autothermal reforming section (20) provided in parallel with respect to other reforming sections (11, 12), and feeding the so produced CO, CO2, H2 and possibly N2 to the carbon monoxide conversion section (13, 14).

Abstract: A cleaning apparatus including a housing holding an air pump, an ozone generator, a high voltage generator, a cooling fan and a bubble generator, wherein a mixing cylinder is connected between the air pump and an ozone output port of the ozonizer to mix ozone from the ozonizer with air from the air pump, permitting the mixture to be guided to the bubble generator for producing air bubbles when the bubble generator is put under water, the mixing cylinder including a stepped cylindrical body having a big diameter section connected to the air pump and a small diameter section longitudinally extended from the big diameter section and connected to the bubble generator, an air outlet at the periphery of the big diameter section, a pipe connected between the air outlet and an air input port of the ozonizer, an ozone inlet at the periphery of the small diameter section, a pipe connected between the ozone inlet and the ozone output port of the ozonizer, and an inside annular flange extended from one end of the small d

Abstract: The present invention's fog generating apparatus has a mixing chamber. A steam nozzle in the mixing chamber injects high pressure steam into the chamber. The injected steam entrains ambient air, pulling it through an air opening into the mixing chamber. The steam and air mix to form humid air. Cryogenic fluid, preferably liquid nitrogen, is injected through a nozzle, which is positioned in the path of the humid air. The cryogenic fluid rapidly cools the warm, humid air which generates large quantities of fog. Depending of the way the steam is injected and the design of the mixing chamber, the present invention can generate slow or fast moving fog.

Abstract: This invention provides a means of achieving the close control of iodine flow rate, temperature of the resulting combined gaseous mixture of iodine in diluent gas, as well as the rapid start and stop response time needed for full-scale laser operation. It comprises an iodine charge stored as a solid and is heated to converted the iodine to a liquid, a means to heat the iodine under pressure to extend the liquid temperature range of iodine, an atomizer for complete vaporization of the iodine, a helium iodine mixer to provide heat for iodine vaporization purporting iodine to helium proportion mass ratio and provides for complete mixing and a flow control system which controls the low iodine flow rates accurately.

Abstract: A low lying fog simulator including a liquid carbon dioxide source and a cooler to be used with a smoke generating machine. The liquid carbon dioxide is forced through an expansion valve to provide a cold carbon dioxide gas pocket through which the smoke passes prior to being dispersed into the ambient. When dispersed into the ambient the cold smoke/carbon dioxide mixture falls toward a level near the earth's surface simulating a low lying fog.

Abstract: An evaporation chamber for forming fine metal particles is separated from a film formation chamber in which the substrate having a metal film such as a metal column thereon is placed during metal film deposition. The pressure of the film formation chamber is set to be lower than that of the evaporation chamber, and the fine metal particles are sprayed on the substrate by the pressure difference to form the metal column. Therefore, a wiring layer, a connection electrode for connecting the wiring layer to another wiring layer, and the like can easily be formed by a small number of steps.

Abstract: A system for continuously filling a plurality of cylinders with a precise concentration of a vaporized liquid component blended into a gas is disclosed wherein the concentration of the liquid component of the resultant final blended mixture is continuously analyzed, and immediately adjusted, during the filling process. Due to the constant analysis and adjustment, any error in the concentration of a component is typically realized before the concentration is outside an acceptable range. The inventive system allows for a large number of cylinders to be accurately and quickly filled with the compressed, final blended mixture.

Abstract: The invention relates to a method and apparatus for reducing steam pressure and temperature in a steam conditioning valve, in which steam flow is regulated with the aid of a valve plug (5) displaceably arranged in a valve seating (4), the plug being perforated by a plurality of holes (6), while cooling water is simultaneously taken into the upper portion (8) of the valve and is regulated in proportion to the regulation of process steam, said water being taken through a hollow valve spindle (7) passing through the plug (5) for discharge through a jet (12) downstream of the center of the departing steam flow. The plug (5) has at least one row of holes (14) in its central region (13). For small opening amounts of the valve (1) process steam is taken through at least one separate duct (15) up to and past the coolant outlet from its openings (16) such as to flow past and break up the coolant, which is ejected from the duct (15) in the vicinity of, and just above the coolant outlet openings (16).

Abstract: The vapour generator for chemical vapour deposition plants allows the extraction of metalorganic vapours from liquid or solid sources. It mainly consists of a container into which a gas flows in, and as it passes near the reagent, it is saturated with the vapours produced and transports them to the reaction chamber. Only the generator is brought to a temperature which is higher than room temperature so as to obtain a vapour which is saturated with a high quantity of reagent. To avoid vapour condensation in the pipe system transporting it from the generator to the reaction chamber, it is diluted with a carrier gas directly in the body of the heated generator, reducing in this way the condensation temperature of vapour which becomes unsaturated. For this purpose, the generator contains a dilution bypass-line in the upper base into which the carrier gas is made to flow. The pipe system going from the generator to the reaction chamber can be held at room temperature without any condensation risks.

Abstract: In systems in which air is introduced into a liquid as a source of oxygen, additional oxygen added independent of the feed air enhances the oxygen content of the liquid source significantly than if the same amount of additional oxygen were combined with the feed air.

Abstract: A high efficiency gas dissolution system is used to dissolve gas in a portion of a body of liquid, improving gas utilization and reducing associated energy requirements. A portion of the body of liquid is recirculated through a mechanical, in-line gas dissolution device wherein a secondary feed gas is dissolved in the liquid.

Abstract: The invention is directed to an arrangement for generating and metering a gas mixture which includes controllable adjusting elements whereby the gas mixture is either conducted through a bypass line past a vaporizer unit to a consumer or is conducted through the vaporizer unit and from there to the consumer. With this arrangement, a calibration of the carrier gas metering especially at low flow quantities is obtained which is continuously reproducible and either carried out manually or automatically without interruption of the metering operation. This is achieved in that a calibrating line opens into a calibrating vessel upstream of the vaporizer unit and the calibrating vessel can be separated by way of shutoff valves from the vaporizer line and a level indicator is connected to the calibrating vessel.

Abstract: A propeller type aeration apparatus for inducing the flow of fluids into a liquid being treated by the rotation of a propeller in the liquid includes an outer housing having a hollow interior, and opposite first and second ends. A drive shaft is supported for rotary motion about its axis within the hollow interior of the outer housing. A motor is connected to a first end of the said drive shaft for rotating the drive shaft. A propeller is attached to a second end of the drive shaft and induces a flow of the liquid in which the propeller is disposed. At least one elongate conduit is attached to an outer surface of the outer housing. One end of the conduit is located adajcent to the propeller and in the path of the flow of the liquid caused by the propeller, and a second end of the conduit is in communication with a fluid to be injected into the liquid.

Abstract: An apparatus for blending two gases together in precisely adjustable proportions. The apparatus includes a mechanically adjustable, blending subassembly adapted to receive the first gas at a predetermined pressure and a one to one force balanced pneumatic relay which is operated by the first gas and which meters the flow of the second gas to the blending subassembly at a pressure substantially equal to the pressure of the first gas being supplied to the blending subassembly.

Abstract: The present disclosure sets forth a method and apparatus for adjusting the rate at which water is introduced as a cooling and decelerating fluid in mist form into a discharge vent for high velocity superheated steam. An optimum measure of water is determined so that the steam is decelerated to a velocity not lower than about 35% of sonic velocity. Moreover, air is educted into the steam flow to further enhance the cooling and deceleration of the steam which is then vented. By the introduction of air and water mist, the steam is cooled and decelerated, thereby avoiding formation of a sonic wave creating unwanted backpressure and avoiding creation of noise.

Abstract: An apparatus for blending two gases together in precisely adjustable proportions. The apparatus includes a mechanically adjustable, blending subassembly adapted to receive the first gas at a predetermined pressure and a one to one force balanced pneumatic relay which is operated by the first gas and which meters the flow of the second gas to the blending subassembly at a pressure substantially equal to the pressure of the first gas being supplied to the blending subassembly.

Abstract: A nebulizer has a mixing chamber into which is projected a high velocity jet of oxygen that aspirates water from a container connected with the mixing chamber. A compressed air input port in the chamber projects a stream of compressed air adjacent to and alongside the oxygen jet to impinge upon the tapered entrance surface of a venturi tube that forms an exit from the mixing chamber. The percentage of oxygen in the output is effectively rendered independent of output back pressure, the lower limit of the amount of oxygen in the output is lowered, the amount of water entrained in the output is increased, and the amount of waste water is decreased.

Abstract: This invention relates generally to the art of gas humidification and more particularly to an improved process for humidifying a gas.

Abstract: A portable gas removal system for withdrawing a flammable gas from a low pressure subterranean formation wherein the gas is aspirated from a well with water, the mixture of gas and water are introduced into a receiving chamber where the aspirated gas is stripped and mixed with air and an air-gas mixture is withdrawn having a gas concentration lower than the explosive limit.

Abstract: A bleach system for blending gaseous chlorine with a paper pulp slurry flow stream by mixing the chlorine with a larger quantity of steam prior to blending the chlorine/steam gas mixture with bleach washer filtrate which serves as carrier water for a multiplied number of gas bubbles entrained in the filtrate. As the cooler filtrate water extracts heat from the mixed gas bubble, the steam constituent condenses to collapse each bubble to a fraction of the original volume thereby providing a larger number of smaller chlorine bubbles than otherwise available from conventional phase mixing injectors.The mixed phase flow stream of chlorine and filtrate is thereafter blended with the pulp slurry flow stream by shear induced turbulence resulting from a greater injection velocity of the mixed phase stream into the center of the slower moving slurry stream.

Abstract: The invention comprises a system for introducing gaseous or vaporized fuels into a carburetor from a storage tank including a regulator connected between the tank and the carburetor for providing a supply of hydrocarbon fuel in a gaseous state at a regulated vapor pressure to a mixing chamber having air and fuel intake ports to blend said hydrocarbon fuel with intake air for injection into the carburetor. In a typical installation, the pressure change of the vacuum manifold alters the pressure within the mixing chamber to draw in fuel and air in proportion to a near constant equivalence ratio, due to the respective areas of the intake ports, over the entire operating range of the engine.

Abstract: A system and method for mixing gaseous fuel with air prior to combustion in an internal combustion engine. The system includes an L-shaped channel with a cap mounted to one end and an inlet formed at the other end. A plurality of holes is formed in the L-shaped channel. The channel is mounted to the air intake system of the internal combustion engine upstream from the air filter such that a partial vacuum is created in the vicinity of the holes as the incoming air flows past the channel. The channel includes means for regulating the flow of gaseous fuel through the channel.

Abstract: A dual fuel system for use with internal combustion engines comprising a manually actuated dual fluid valve which alternatively supplies gasoline to the engine's carburetor or engine intake manifold vacuum to a single-stage liquified gas to gaseous fuel converter having a liquified fuel inlet valve actuated in response to intake manifold vacuum by a diaphragm of substantially the same diameter as a second diaphragm which actuates a valve to a converter gaseous expansion chamber where desired gaseous pressure is maintained and is automatically reduced during cruise conditions by compression of a bellows which acts on the second diaphragm in response to reduced engine intake manifold pressure during such cruise conditions, and a pressurized gaseous fuel and air mixer having a plunger structure responsive to venturi vacuum which meters air flow and actuates a valve needle to meter fuel flow.

Abstract: A system and method for mixing gaseous fuel with air prior to combustion in an internal combustion engine. The system includes an L-shaped channel with a cap mounted to one end and an inlet formed at the other end. A plurality of holes is formed in the L-shaped channel. The channel is mounted to the air intake system of the internal combustion engine upstream from the air filter such that a partial vacuum is created in the vicinity of the holes as the incoming air flows past the channel. The channel includes means for regulating the flow of gaseous fuel through the channel.

Abstract: Disclosed herein is an apparatus which is adapted for controlling operation of an internal combustion engine which is selectively operable using gaseous fuel or liquid fuel, and which comprises a gaseous fuel supply line extending between the engine and a source of gaseous fuel, a liquid fuel supply line extending between the engine and a source of liquid fuel, and a control for controlling supply to the engine of the gaseous fuel and the liquid fuel, which control includes an operator controlled fuel selector switch movable between a gaseous fuel position and a liquid fuel position, which control is operable following prior engine operation with gaseous fuel and in response to movement of the fuel selector switch from the gaseous fuel position to the liquid fuel position for permitting liquid fuel flow through the liquid fuel supply line, for permitting continued gaseous fuel flow through the gaseous fuel supply line until initiation of liquid fuel combustion, and thereafter preventing further gaseous fuel f

Abstract: An attachment within the air cleaner housing of a liquid-fuel internal-combustion engine, the attachment having a circumferential venturi air passage and a gaseous fuel inlet slot inboard of the narrowest portion of the venturi air passage.

Abstract: An attachment for operating an internal combustion engine on either gaseous or liquid fuel incorporates a modified air cleaner assembly having a cover and an annular adapter between which is sandwiched a typical annular filter element, the adapter fitting over the engine air intake. A diaphragm movably mounts a circular diaphragm plate to the cover to form a chamber therewith on one side of the diaphragm plate and an annular venturi between the other side of the diaphragm plate and the adapter. In one version gaseous fuel is admitted into the chamber through an inlet fitting secured to the cover and thence through ports in the diaphragm plate into the venturi. In another version the gaseous fuel is admitted through an inlet fitting secured to the adapter and thence into the venturi through ports in the adapter, a hose connecting the inlet fitting and the chamber.

Abstract: An arrangement for switching a carburetor in an internal combustion engine in a vehicle adapted for alternative operation on liquid or gaseous fuel. The carburetor is of the type where the pressure upstream of a throttle butterfly determines the engine air and fuel supply by the actuation of a piston provided with a metering needle. When using liquid fuel, the piston executes upward and downward movements, a passage leading through the carburetor thereby being constricted to a varying degree, and similarly the needle is caused to be thrust to a varying degree into a nozzle for metering liquid fuel to the engine induction air. This signifies too rapid wear of the metering needle in alternating operation on liquid and gaseous fuel.

Abstract: A carburetor includes means for detecting the volume of a first fuel such as gasoline within a float chamber, and valve means for preventing a second fuel such as LPG from being fed into an induction passage leading to an engine when the volume of the first fuel within the float chamber is above a predetermined value. The second fuel is prevented from being fed into the induction passage until the volume of the first fuel within the float chamber is decreased to a small amount or zero. Thus, the air-fuel mixture within the induction passage is not enriched too much after the fuel supply is changed from the first fuel to the second fuel.

Abstract: A slow-run system for gaseous fueled internal combustion engines, including gaseous fuel conversions of liquid fuel engines for alternate operation on either fuel, employs a valve having an inlet receiving gaseous fuel from between the primary regulator and zero pressure governor and an outlet emptying into the air cleaner assembly upstream of the liquid fuel carburetor or equivalent means. The valve is actuated through a connection into the engine air intake manifold or similar passage below the throttle such that the valve opens to supply gaseous fuel to the air cleaner assembly during slow-run when manifold vacuum is high and remains open throughout substantially all of the engine's operating range.