Abstract: A control system is provided for a mist scrubbing process in which a gas containing odorous and acidic contaminants is cocurrently contacted in a reaction chamber with tiny droplets of an aqueous reagent to react with and destroy the contaminants. The reagent contains an oxidizing agent and a base and the process is controlled by measuring a property, typically pH, of spent spray liquid settling at the bottom of the chamber. That measurement is used to meter the flow rate of base into the system while at the same time the concentration of an acidic contaminant in the scrubbed gas stream leaving the reaction chamber is measured and that measurement is used to meter the injection rate of an oxidizing agent into the system.

Abstract: The insulated walls of a refrigerator chamber are pressurized so as to maintain a pressure within the insulated interior of the walls that is slightly higher than the exterior ambient air pressure. This is accomplished by means of small fans or the like blowing outwardly and mounted on the interior of the walls.

Abstract: Odoriferous vapors, such as those from plants for rendering fats, for example, are treated in a two-chamber system. Vapors having a high odor content, such as those from rendering cookers and presses, enter a first high intensity odor treatment chamber at the top, and are treated with a water spray or sprays, the latter containing an oxidant, NaOCl, for example, or H.sub.2 SO.sub.4, at a relatively high concentration of liquid droplets per cubic foot and a relatively longer reaction time in the order of 20 seconds. Treated vapors exit this chamber from its lower portion and are led into a duct conveying low odor intensity vapors, such as rendering plant ventilation odors, into a second, lower intensity odor treatment chamber. The second chamber contains a spray nozzle which sprays water droplets of lesser concentration into the vapors, the said droplets also containing a treating agent. In the second chamber the reaction time is relatively shorter in the order of about three seconds.

Abstract: The frequency of explosive events in mills and other processing equipment is reduced and their severity lessened by introducing an aqueous microdroplet dispersion of controlled particle size range into the equipment under conditions such as to ensure survival of an adequate microdroplet population during transit through the equipment. Droplet diameter is limited to a size range of less than about 20 microns so as to avoid impingement stripping of the droplets from suspension and the relative humidity of an air stream passing through the equipment is adjusted to avoid droplet loss through evaporation.

Abstract: A jet pump or ejector employing steam as the motive fluid is used to produce a dispersion of fog-like liquid droplets containing a reactive chemical in a gas stream. A solution of the reactive chemical is metered to the suction side of the ejector which discharges into the gas stream. Temperature and relative humidity of the gas stream are maintained at levels whereat the ejector discharge condenses to form very tiny liquid droplets containing the reactive chemical.

Abstract: Apparatus, particularly adapted to the removal of odorous constituents from waste gas streams, is described. The apparatus comprises a treatment vessel or chamber preferably of cylindrical shape containing a coaxially-mounted exhaust duct which serves also as a columnar support for the chamber top or roof. An odorous gas is introduced tangentially into an upper portion of the reactor and is caused to move in a spiral flow around the central column and to exahust through an exit port into the central duct adjacent the chamber floor. An arcuate, spiral baffle is mounted on the chamber floor and extends continuously from the inner vessel wall to the central duct thereby directing gas flow into the exit port to reduce pressure drop through the treatment chamber. A finely divided spray of a reagent reactive toward the odorous compound is introduced into the chamber through nozzles ringing the chamber wall or mounted in the chamber roof.

Abstract: Apparatus, particularly adapted to the removal of odorous constituents from waste gas streams, is described. The apparatus comprises a treatment vessel or chamber preferably of cylindrical shape containing a coaxially-mounted exhaust duct which serves also as a columnar support for the chamber top or roof. As odorous gas is introduced tangentially into an upper portion of the reactor and is caused to move in a spiral flow around the central column. A finely-divided spray of a reagent reactive toward the odorous compound is introduced into the chamber through nozzles ringing the chamber wall or mounted in the chamber roof. Reagent droplets coalesce on the chamber floor and are removed from the vessel. The treated gas exhausts up the central duct through openings located near the bottom thereof.

Abstract: Particulate laden gas, especially those gases carrying particulates having a size in the micron or submicron range, are removed by humidifying the gas with water and thereafter subjecting the gas to indirect contact heat exchange sufficient to provide an energy transfer for water vapor condensation of at least 5 horsepower per 1000 cfm. Heat exchange is accomlished by passing the gas downwardly through an exchange element having smooth and vertical gas passages of a relatively large dimension.

Abstract: Odoriferous constituents are removed from relatively dry and/or warm gas streams by contacting the gas with a very finely divided aqueous spray containing a reagent reactive toward the odoriferous constituents of the gas. Droplet size of the aqueous spray is controlled as a function of temperature and relative humidity of the gas stream so as to prevent complete evaporation of liquid droplets and to achieve a maximum droplet size after evaporation of about ten microns.

Abstract: Two or more liquid reagents are caused to react simultaneously within the same reaction vessel with different components of a gas stream. The gas stream being treated is introduced into the top of a reaction vessel and is withdrawn from the bottom. A first chemical reagent is introduced into the top of the vessel in the form of a finely divided spray. The second liquid reagent is introduced in like fashion at a lower level. The two sprays are allowed to travel unimpeded to the bottom of the tower while reacting with different components of the gas stream.

Abstract: A pressure relief valve includes a flexible sheet bonded, except for a series of adhesive-free areas and channels therebetween, to a container having one or more holes in communication with said adhesive-free areas. The adhesive, preferably pressure-sensitive adhesive, is printed on the sheet in a fashion which, when bonded to the container, forms the adhesive-free areas and channels. When a gas pressure, as for example, derived from food generated gases, builds up within the container, the force of the gas exerted on the flexible sheet causes the sheet to bulge, thereby forming a cavity over the adhesive-free area. The gas then seeps through any series of channels in communication with said cavity and is released to the atmosphere. After the internal gas pressure has been relieved, the flexible sheet returns to its original position (flush against the container) thereby preventing the ingress of atmospheric gases.

Abstract: Exhaust gases, such as those produced by the incineration of municipal refuse, are cleaned by water scrubbing the gases in an open tower and thereafter further cooling the gases by heat exchange to condense water vapor and to trap and remove particulate material and other contaminants. Fouling and plugging of the heat exchanger during the condensation step is avoided by use of a spiral flow-cross flow type of heat exchange element.

Abstract: An apparatus and process for treating gases containing odoriferous constituents is described. The gas is passed through a condenser to remove the condensable materials and the non-condensed portion is then introduced into the top portion treating vessel. There it is contacted with a finely divided aqueous spray having a droplet diameter of up to 10 microns in diameter, whereby odoriferous constituents are removed. The treated gas is removed from the vessel at the bottom through a duct. Outside air may be introduced through a damper to mix with the exit gas, which is substantially saturated with moisture, to lower its dew point.

Abstract: A refrigerated chamber or building having an upper crawl space above the ceiling wherein the crawlspace is maintained under a negative pressure in order to provide an outflow of refrigerated air through the insulation into the crawlspace. This serves to prevent the inflow of warm air into the upper portions of the refrigeration chamber, which normally would have a negative pressure, with accompanying harmful moisture precipitation in the insulation.

Abstract: A method is provided for inhibiting microbial spoilage and discoloration of edible meat comprising contacting the external surfaces of said meat with an aqueous hypochlorous acid solution, the solution being at a pH related to the elapsed time after the slaughter of the meat animal so that the growth of salmonella organisms is inhibited.