Patent Publication Number: US-2007107983-A1

Title: GN2 exhaust muffler

Description:
TECHNICAL FIELD  
      The present invention relates generally to exhaust mufflers and in particular to GN 2  exhaust mufflers.  
     BACKGROUND  
      The use of liquid nitrogen LN 2  for processes in industry has many applications. For example, LN 2  is used in some types of heat exchangers. In a heat exchanger system, thermal energy is transferred between a fluid like LN 2  in a first thermally conductive container and a working fluid in a second thermally conductive container. The LN 2  when placed in the confined space of a thermally conductive container of a heat exchanger will turn into gas (GN 2 ) at a rate of about 750:1. Accordingly, a small amount of LN 2  results in a large amount of GN 2  gas. In some heat exchange systems the gas is expelled through a nozzle at a relatively high velocity. Because of the high volume and high velocity of the expelled GN 2  exhaust flow, the expelling of the gas is extremely noisy. One method used to alleviate the problem in the past was to plum the exhaust outside the building that housed the heat exchanger. However, with systems that use small amounts of LN 2  that do not require the gas to be exhausted outside for ventilation reasons, the cost and inconvenience of having to plumb the exhaust outside can be prohibitive. Moreover, the portability of a system that produces a GN 2  exhaust flow is limited when the exhaust flow has to be plumbed outside of the building.  
      For the reasons stated above and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for a method of effectively reducing the noise associated with the exhaust of systems.  
     SUMMARY OF INVENTION  
      The above-mentioned problems of current systems are addressed by embodiments of the present invention and will be understood by reading and studying the following specification.  
      In one embodiment gas nitrogen (GN 2 ) exhaust muffler is provided. The GN 2  exhaust muffler includes a first pipe and a second pipe. The first pipe has a first end and a second end. The first end of the first pipe is capped. The first pipe also includes a plurality of apertures that are positioned near the capped first end. The second end of the first pipe is adapted to receive a flow of GN 2  exhaust. The second pipe encases a portion of the first pipe such that the capped end and the plurality of apertures are housed in the second pipe. Moreover, the second pipe has an exhaust outlet adapted to output the GN 2  exhaust.  
      In another embodiment, a method of manufacturing a gas nitrogen (GN2) exhaust muffler is provided. The method includes capping a first end of a first pipe that is adapted to receive a flow of GN2 exhaust in a second end. Forming a plurality of apertures in the first pipe near the first cap and encasing a portion of the first pipe with a second pipe such that the cap and the plurality of apertures are housed in the second pipe.  
      In yet another embodiment, a method of operating a gas nitrogen (GN 2 ) exhaust muffler is provided. The method comprises receiving a GN 2  exhaust flow in an inlet of a first pipe. Forcing the GN 2  exhaust flow out of a plurality of relatively small apertures in the first pipe and directing the flow of GN 2  exhaust out of an outlet of a second pipe, wherein the second pipe encases a portion of the first pipe having the relatively small apertures.  
      In still yet another embodiment, a method of processing a flow of gas nitrogen (GN 2 ) exhaust is provided. The method comprises directing the flow of GN 2  exhaust through a muffler to reduce the noise produced by the flow of GN 2 . 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The present invention can be more easily understood and further advantages and uses thereof more readily apparent, when considered in view of the description of the preferred embodiments and the following figures in which:  
       FIG. 1  is a cross-sectional side view of an exhaust muffler of one embodiment of the present invention;  
       FIG. 2  is a flow diagram of the use of an exhaust muffler of one embodiment of the present invention; and  
       FIG. 3  is a flow diagram of the manufacturing of one embodiment of the present invention. 
    
    
      In accordance with common practice, the various described features are not drawn to scale but are drawn to emphasize specific features relevant to the present invention. Reference characters denote like elements throughout Figures and text.  
     DETAILED DESCRIPTION  
      In the following detailed description, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the inventions may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that logical, mechanical and electrical changes may be made without departing from the spirit and scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the claims and equivalents thereof.  
      Embodiments of the present invention provide a GN 2  exhaust muffler that reduces the noise produced by a GN 2  exhaust flow so that a system that expels a high pressure GN 2  exhaust flow can be used in an enclosed room without having to plum the exhaust outside the room. This also allows for the system expelling the GN 2  exhaust flow to be portable.  
      Referring to  FIG. 1 , a cross-sectional side view of one embodiment of a GN 2  exhaust muffler  100  of the present invention is provided. This embodiment includes a first pipe  102  and a second pipe  105 . The first pipe  102  has a first end  103  that is covered with a cap  107 . The first pipe  102  also has a second end  106  that receives a flow of GN 2  exhaust from a system using LN 2 . Also illustrated in the first pipe  102  is a plurality of apertures designated generally as  110 . The flow of GN 2  exhaust received by the inlet  106  (or second end  106 ) flows out of the plurality of apertures  110 . A portion of the second pipe  104  encases a portion of the first pipe  102  such that, as illustrated in  FIG. 1 , the plurality of apertures  110  and the first end  103  of the first pipe  102  is housed in the second pipe  104 . In the embodiment of  FIG. 1 , the second pipe  104  includes a neck  105  that has a diameter that is less then the diameter of other portions of the second pipe  104 . The second pipe  108  further includes an exhaust outlet  108  in which the GN 2  exhaust exits the GN 2  exhaust muffler  100 .  
      In some embodiments of the present invention, the first and second pipes are made from materials that can handle the cold temperatures of the GN 2  exhaust flow as well as further dampen the noise created by the GN 2  exhaust. The materials include but are not limited to plastics (and one embodiment soft plastics), rubber and the like. Besides being able to handle the cold temperatures and dampening the noise, these materials are also not very susceptible to condensation build up as the GN 2  exhaust flows through. In other embodiments, other types of materials are used to form the first and second pipes  102  and  104  and this invention is not limited to the above mentioned materials.  
      Referring to  FIG. 2 , a flow diagram  200  illustrating a method of handling GN2 exhaust, of one embodiment is illustrated. As illustrated, the process starts by receiving a GN2 exhaust flow from a device at an inlet of a first pipe ( 202 ). The device may be any device that uses LN 2  in its processes and releases a GN 2  exhaust flow. This type of device may include but is not limited to heat exchange systems. The GN 2  exhaust received at the inlet is forced through a plurality of relatively small apertures formed in the first pipe ( 204 ). The GN 2  exhaust gas is then output through an exhaust outlet in the second pipe ( 206 ).  
       FIG. 3 , is a flow diagram  300  of the process forming a GN 2  exhaust muffler of one embodiment of the present invention. In this embodiment, the process includes forming a bend in a first pipe ( 302 ). The bend in the first pipe is to direct the flow of GN 2  exhaust away from a working area or from the device expelling the GN 2  exhaust flow. A first end of the first pipe is capped to prevent the flow of exhaust through the first end ( 304 ). A second end of the pipe is designed to receive a flow of GN 2  exhaust. A plurality of apertures are formed in the first pipe near its first end ( 306 ). A portion of the first pipe is encased with a second pipe such that the plurality of apertures and the first end of the first pipe are housed in the second pipe ( 308 ). A neck having a relatively small diameter is formed in the second pipe ( 310 ). The neck portion is designed to expel the GN 2  exhaust flow from the GN 2  muffler. In one embodiment the neck portion is formed from the second pipe and another embodiment, the neck is coupled to the second pipe.  
      Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement, which is calculated to achieve the same purpose, may be substituted for the specific embodiment shown. This application is intended to cover any adaptations or variations of the present invention. Therefore, it is manifestly intended that this invention be limited only by the claims and the equivalents thereof.