摘要:
A pressure-flow reducer, and an aerosol focusing system incorporating such a pressure-flow reducer, for performing high-flow, atmosphere-pressure sampling while delivering a tightly focused particle beam in vacuum via an aerodynamic focusing lens stack. The pressure-flow reducer has an inlet nozzle for adjusting the sampling flow rate, a pressure-flow reduction region with a skimmer and pumping ports for reducing the pressure and flow to enable interfacing with low pressure, low flow aerosol focusing devices, and a relaxation chamber for slowing or stopping aerosol particles. In this manner, the pressure-flow reducer decouples pressure from flow, and enables aerosol sampling at atmospheric pressure and at rates greater than 1 liter per minute.
摘要:
A storage box 100, on the bottom surface of which are attached casters 101, has a heater 102 positioned on the bottom surface thereof and left-hand side and the right-hand side interior spaces being divided by a partition plate 103, wherein nine (9) sampling bags 104 . . . in total can be received within a wide space at the right-hand side thereof. On one side of the storage box 100 is provided a connector unit 110. This connector unit 110 is constructed with an elevating block 112 hooking on guide rails provided in a direction of up and down, and the elevating block 112 is biased upward with a gas spring 113. In guide holders 112b of the elevating block 112 are provided guides 115 . . . in the same number as the number of the sampling bags 104, and into each guide 115 is inserted a flexible conduit 116 made from stainless steel, in a such manner that it can be drawn out therefrom. Heaters and warm air passages are provided to prevent the condensation of moisture within a sampled gas under a range of operating conditions.
摘要:
An exhaust gas sampling apparatus for analyzing the contents in exhaust gas. The sampling apparatus intakes air from an air intake conduit and mixes the air with exhaust gas taken from an exhaust gas supply conduit. The mixed gas can be sampled in different sampling conduits based upon the type of exhaust gas being examined. The apparatus includes heaters for heating various conduits to prevent condensation from forming within the conduits.
摘要:
A gas sampling system utilizes small sample vacuum transport to reduce the dew point of the sample. A vacuum pump maintains a substantial vacuum on the sampling system causing a sample, drawn at a rate less than a liter per minute, to be drawn and transported under partial vacuum for analysis. A dryer can be placed near the sampling probe to further reduce the dew point prior to the vacuum transport. The dew point of the sample is affected by both the dryer and the degree of vacuum transporting the gas mixture. As such, the dew point can be varied indefinitely by any reasonable combination of moisture removal by the dryer and vacuum pump strength.
摘要:
A gas sampling system utilizing a pair of parallel sonic orifices. One of the orifices is connected to a source of filtered, heated samples. The second, larger orifice is connected to a source of dilution gas. A vacuum pump maintains a substantial vacuum behind the orifices, thus assuring critical flow therethrough. The sample and diffusion gas are mixed behind the orifices and transported under partial vacuum for analysis. The dew point of the sample is affected by both the ratio of the diameter of orifices and the degree of vacuum transporting the gas mixture. As such, the dew point can be varied indefinitely by any reasonable combination of orifice ratio and vacuum pump strength.
摘要:
A constant flow rate controller apparatus for an aerosol sampler using a filter includes an enclosed channel for channeling a stream of air, a filter positioned in the channel to capture and retain particles while allowing the stream of air to flow therethrough, an air or vacuum pump to pull the air through the filter, and a flow controller that maintains a constant volumetric flow rate of air through the sampler and filter, regardless of how much particulate matter is deposited on the filter or how much pressure drop across the filter changes due to particulate loading. The filter can be a substantially non-fibrous, porous, this film membrane medium, for which the flow controller of this invention is particularly beneficial, or it can be a more conventional fibrous medium. The flow controller can include a critical or choked flow orifice with a variable effective flow area, which effective flow area can be varied in response to changes in pressure drop across the filter to maintain constant volumetric flow rate. An expandable and contractible bellows with an appropriate spring constant can be used to both sense changes in air pressure drop across the filter or changes in stagnation pressure downstream of the filter and to actuate a variation in the effective flow area of the orifice in response to such changes in air pressure to maintain constant volumetric flow rate of the air. The air or vacuum pump has to have enough capacity to maintain critical or choked flow conditions in the orifice.
摘要:
A gas sampling device includes a dilution tunnel of particularly effective construction that reduces contamination or soiling of the ducting leading to a filter assembly and improves the accuracy of the results. The gas sampling device has a sampling probe disposable in the gas stream of an engine or the like, and a controlled source of clean and pressurized diluent air. The dilution tunnel includes an air distribution tube defining a plurality of distribution holes therethrough, a collar defining a first annular chamber about the air distribution tube that is connected to the air source, and a porous center tube having a plurality of micron-sized pores connected between the sampling probe and the filter assembly. A second annular chamber is defined between both tubes, and the diluent air supplied thereto is uniformly passed through the porous center tube to effect good mixing of the exhaust gas and diluent air while providing a boundary layer of diluent air that keeps the center tube clean. An alternate embodiment gas sampling device employing master and slave mass flow controllers is also disclosed.
摘要:
Disclosed is an analyzer for determining volatile composition changes of a distillable material which comprises: (a) a first device for causing at least a portion of said material to be at a temperature and at a pressure so that a difference in temperature of said portion of said material across an isenthalpic expansion at critical flow conditions would be at least about 5.degree. F.; (b) a second device for carrying out said isenthalpic expansion on said at least a portion of said material; (c) a third device for measuring at least two temperatures of said material where said at least two temperatures are a first and a second temperature, said first temperature being measured upstream of said expansion and said second temperature being measured downstream from said expansion; and (d) a fourth device for maintaining pressure downstream of said expansion to a value which does not vary by an amount in excess of about 20% of said pressure downstream of said expansion. The disclosed analyzer can be used in conjunction with equipment useful for processing distillable material into various boiling fractions. Disclosed also is a particular application for the analyzer in an online configuration for refining of petroleum crudes.
摘要:
Apparatus for sampling gaseous exhaust emissions, on a constant flow basis. A centrifugal type extractor pump is used to draw gas through a critical flow venturi of predetermined flow rate. Exhaust emissions are diluted with air and the critical flow venturi acts as a constant volume flow device serving a metering function. Samples are taken and collected continuously during the test run, and are available to be analyzed for contaminants such for example as hydrocarbon, carbon monoxide and oxides of nitrogen.