Patent Publication Number: US-11035384-B2

Title: Silencer for an air blower assembly and air blower assembly having the silencer

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority, under 35 U.S.C. § 119, of U.S. provisional patent application No. 62/662,291, filed Apr. 25, 2018; the prior application is herewith incorporated by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The invention relates in general to silencers that are part of or retrofitted to blower assemblies. 
     Automated carwash installations are generally equipped with air blowing dryers for drying passing vehicles. Unfortunately, the air blowing dryers are extremely noisy and their high sound output levels create problems with customers, local residents, as well as employees who may suffer ear damage if they do not wear ear protection. In general, conventional dryers have blowers that are powered by electric motors of high horsepower providing the force necessary to propel air along the path of travel. A large percentage of the blowers used for carwash dryers are powered by motors of varying but high horsepower (HP). Each blower is a fan assembly, with its own electric motor, impeller and housing. A drying system typically is composed of multiple blowers, the total HP for a drying system can add up to more than 100 HP. 
     Unfortunately such large horsepower motors produce a large amount of noise. There is therefore the need to silence existing motors and new fan assemblies as best as possible and thus to reduce noise pollution. 
     SUMMARY OF THE INVENTION 
     It is accordingly an object of the invention to provide a silencer that can be retrofitted to an existing blower assembly used in an automated carwash that overcomes the above-mentioned disadvantages of the prior art devices of this general type. In addition, new blower assemblies can be provided with a built-in silencer. 
     With the foregoing and other objects in view there is provided, in accordance with the invention, a blower assembly. The blower assembly has a main housing with an air inlet opening and an air inlet housing disposed around the air inlet opening and connected to the main housing. The air inlet housing defines an air inlet channel leading into the air inlet opening in the main housing. An air outlet channel is connected to the main housing and defines an air outlet from the main housing, the air outlet is fluidically connected to the air inlet channel. A fan is disposed in the main housing for driving an airflow through the air inlet channel to the air outlet. A silencer covers the air inlet housing and directs air into the air inlet channel. 
     In accordance with an added feature of the invention, the silencer has a plurality of airflow openings for directing the air into the air inlet channel. Furthermore, the silencer has slidable coverings for individually opening and closing the airflow openings for controlling an amount of the airflow into the air inlet channel. 
     In accordance with another feature of the invention, the silencer has a silencer housing surrounding the air inlet housing. The silencer housing is connected to the air inlet housing and/or the main housing. 
     In accordance with a further feature of the invention, the silencer housing includes a cylindrical lower housing part and a cylindrical upper housing part. The cylindrical upper housing part has a first diameter being greater than a second diameter of the cylindrical lower housing part. The silencer housing further has an end cover attached to one end of the cylindrical upper housing part. 
     In accordance with an additional feature of the invention, a sound deadening material is disposed on an inner wall of the end cover. The sound deadening material is ideally further disposed on the inner cylindrical walls of the cylindrical upper housing part. Ideally, the sound deadening material is a foam material having an egg crate shape although many other shapes and materials are possible. 
     In accordance with yet another feature of the invention, the cylindrical upper housing part has a first end supporting the end cover and a second end with a protrusion extending toward an interior of the silencer housing. The protrusion supports an outer surface of the cylindrical lower housing part. In this manner, the cylindrical lower housing part is nestled within the cylindrical upper housing part. Although the upper and lower housing parts are ideally cylindrical in shape, other shapes such as square shaped, rectangular shaped or U-shaped are possible. 
     In accordance with another further feature of the invention, the air flow openings are only formed in the cylindrical upper housing part. 
     In accordance with a concomitant feature of the invention, the cylindrical lower housing part has an outer rim with at least two recesses for receiving fasteners for attaching the silencer housing to the air inlet housing and/or the main housing. 
     With the foregoing and other objects in view there is provided, in accordance with the invention, a silencer for attaching to a blower assembly. The silencer contains a silencer housing having a lower housing part and an upper housing part with a plurality of airflow openings for providing an airflow stream into an interior of the silencer housing. A noise cancelling material is disposed at least in the upper housing part. 
     In accordance with an added feature of the invention, the upper housing part has a circumference and six airflow openings are disposed around the circumference. 
     Other features which are considered as characteristic for the invention are set forth in the appended claims. 
     Although the invention is illustrated and described herein as embodied in a silencer for an air blower and an air blower having the silencer, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. 
     The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         FIG. 1  is a perspective view of a blower assembly having a silencer attached thereto according to the invention; 
         FIG. 2  is a perspective view of the blower assembly without the silencer; 
         FIG. 3  is a diagrammatic, perspective view of the silencer; 
         FIG. 4  is a side view of the silencer; 
         FIG. 5  a sectional view of the silencer taken along the line V-V shown in  FIG. 4 ; 
         FIG. 6  is a sectional view of the silencer taken along the line VI-VI shown in  FIG. 4 ; and 
         FIG. 7  is a further diagrammatic, perspective view of the silencer showing an insulating material. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the figures of the drawings in detail and first, particularly to  FIGS. 1 and 2  thereof, there is shown a blower assembly  1  having a main housing  2  containing a fan assembly  3  (see  FIG. 2 ), an air inlet  4  and an air or blower outlet  7  defined by an outlet channel  8 . The blower assembly  1  has a silencer  5  covering or limiting the air inlet  4 . 
       FIG. 2  shows the blower assembly  1  with the silencer  5  removed. After the silencer  5 , the air inlet  4  or air inlet path is defined by an inlet housing  6  disposed in front of the fan assembly  3 . The fan assembly  3  is driven by a non-illustrated fan motor disposed on an opposite side of the main housing  2 . The fan assembly  3  sucks in a high quantity of air via the air inlet  4 . However, and as noted above, the non-illustrated motor, the rotating fan assembly  3  and the incoming air flow traversing the air inlet  4  create an abundance of noise which is abated to a large degree by the silencer  5 . 
       FIGS. 3-7  show various views of the silencer  5 . As shown in  FIGS. 1 and 3 , the silencer  5  has a noise canceling silencer housing  10  that is attached over the air inlet  4  of the blower assembly  1 . More specifically, the silencer housing  10  has a lower housing part  11  that has a main frontal opening  12  that is configured to slide over the air inlet  4  and is attached using zip screws from the side to the inlet housing  6  and/or the main housing  2 . The lower housing part  11  has a cylindrical or circular shape which is preferable due to its symmetry but could conceivably be rectangular, square or even U-shaped. 
     The silencer housing  10  has an upper housing part  13  with a plurality of airflow openings  14  and a cap  15  covering an end side of the upper housing part  13 . The upper housing part  13  is also cylindrical or circular shaped. Air coming into the blower assembly  1  is re-directed to come in from the six airflow openings  14 . The airflow openings  14  are ideally spaced equally apart and symmetrically around a circumference of the upper housing part  13 . Although  FIG. 3  shows six openings  14 , any number of openings can be provided in dependence on airflow needs and tolerable noise levels, for example anywhere from  2  to  10  airflow openings  14  are envisioned. In addition, the individual airflow openings  14  can have a closing cover  18  so that the airflow opening  14  can be individually opened fully, opened partially or closed for increasing or decreasing the airflow and the noise level. The closing covers  18  having tabs  19  and are manually slidably for allowing a partial to full closing of the airflow openings  14 . The airflow openings  14  are shown to be rectangular in shape but may have different shapes such as circular, square, trapezoid, etc. 
     By having the air inlet  4  mostly covered over 360 degrees by the silencer  5  it keeps the noise caused by the fan assembly  3  and air flow contained within the silencer  5  and housings  2 ,  6  and reduces the number of surfaces that the noise can bounce off of while maintaining an adequate air flow. 
     The upper housing part  13  is also cylindrical shaped and has a diameter d 2  which is greater than a diameter d 1  of the lower housing part  11 . The two housing parts  11 ,  13  are connected at an inner step or protrusion  16  of the upper housing part  13 . The upper housing part  13  supports the lower housing part  11  at or by the step or protrusion  16 . 
     As best shown in  FIG. 7 , the noise cancelling housing  10  is lined with a noise cancelling material  17  such as but not limited to foam. The foam  17  ideally has an egg crate configuration or shape with an adhesive backing. The noise cancelling material  17  can be added to one or multiple walls of the noise cancelling housing  10  and is attached there preferably by an adhesive connection (e.g. glued) but other connections methods are possible (e.g. riveted, screwed, etc).  FIG. 7  further shows slots  20  formed at an outer rim  21  in which non-illustrated fasteners (e.g. bolts) can penetrate through for attaching the silencer  5  to the inlet housing  6  of the blower assembly  1 . 
     The silencer housing  10  can be made from a metal, plastic or composite material. 
     As can be easily deduced from the drawings the silencer  5  can be an integrated feature in newly produced blower assemblies  1  or it can be retrofitted onto an existing blower assembly  1 . 
     In operation, air coming into the blower assembly  1  is re-directed and limited by the airflow openings  14 . The number and size of the openings  14  can be customized to a consumer&#39;s operational needs. The silencer  5  controls the direction of air flow into the air inflow channel  4  and also provides acoustic soundproofing. More specifically, the airflow openings  14  are perpendicular the main air inflow channel  4 . Thus noises coming from the fan assembly  3  and the air flow stream are absorbed by the noise cancelling material  17  and the walls of the silencer  5 . It is noted that the 90 degrees turn by the airflow entering from the outside into airflow channel  4  assists in abating noise. More specifically, exiting noise will first strike the noise cancelling material  17  and the walls of the silencer  5 . 
     The design intent is to create a silencer  5  or silencer kit  5  for retrofit applications, which is bolted onto the inlet airflow side of the blower fan assembly  1  in order to reduce noise levels caused by the blower assembly&#39;s operation. The silencer  5  is principle ideally used in blower assemblies  1  intended to dry vehicles in carwash applications, namely blower dryers. 
     By directing air from limited directions, noise is directed in a direction of flow coming into the inlet which decreases the sound waves going into adjacent walls. The sound absorbing material  17  on the inside of the housing  10  further reduces the sound waves emitted as the air is forced inside the blower assembly  1 . 
     As can be easily deduced from the drawings the silencer  5  can be an integrated feature in newly produced blower assemblies  1  or it can be retrofitted onto an existing blower assembly  1 .