This invention relates to a Venturi control valve that is used to control the flow of air through a duct system of a heating, ventilation, and air-conditioning (HVAC) system, and more particularly, the invention relates to a packless silencer that is closely connected to the Venturi control valve to suppress the noise created by the Venturi control valve.
A conventional HVAC system includes a duct system for directing the flow of air into and out of an occupied space that is heated, ventilated, or cooled by the HVAC system. In order to control the flow of air through one region of the duct system, control valves may be placed within the duct system to limit the flow of air to one region or another of the occupied space. A Venturi control valve, such as that disclosed in Lorch et al. U.S. Patent Application Publication No. 2002/0162589, is conventionally used to control the flow of air through a portion of the duct system. Such a Venturi control valve provides a constant volume of air flow over a range of pressures within the duct system. Such Venturi control valves, however, generate excess noise that may be annoying to persons occupying the space that is heated, ventilated, or cooled by the HVAC system.
Conventional silencers used with Venturi control valves include Helmholtz resonator silencers, such as that disclosed in Lorch et al. U.S. Pat. No. 6,116,375, packless silencers, such as that disclosed in Ingard U.S. Pat. No. 4,287,962, and silencers packed with acoustical material, such as foam, rock-wool, fiberglass, etc. Typically, silencers for Venturi control valves are spaced away from the Venturi control valve by at least 3 feet or more.
Therefore, there is a need to suppress the noise created by the Venturi control valves where the available space around the Venturi control valve is limited.
In order to suppress the noise created by a conventional Venturi control valve within a limited space, the present invention includes an inlet silencer for the exhaust Venturi control valve or an outlet silencer for the supply Venturi control valve. The inlet silencer comprises four side walls defining a generally, rectangular inlet silencer housing with an intake opening and a discharge opening. Similarly, the outlet silencer comprises four side walls defining a generally, rectangular outlet silencer housing with an intake opening and a discharge opening. The inlet silencer, in accordance with the present invention, is directly connected to an inlet opening of the Venturi control valve, and the outlet silencer, in accordance with the present invention, is directly connected to an outlet opening of the Venturi control valve. The inlet silencer and the outlet silencer are closely coupled to the Venturi control valve, and each is no greater than 24 inches in length (in the air flow direction). Typically in the industry, 3 feet of air duct is interposed between conventional silencers and the Venturi control valve.
Moreover, the inlet silencer and the outlet silencer are packless silencers with no acoustical material, such as foam, rock-wool, fiberglass etc., installed inside the walls of the inlet silencer and the outlet silencer. Instead, the inlet silencer and the outlet silencer are each lined with perforated metal baffles spaced inwardly approximately one inch from the side walls along the full length of the silencer housing thereby creating a baffle space between the perforated baffles and the side walls. No acoustical material (insulation) is present in the baffle space between the perforated baffles and the side walls of the silencer housing. A set of reinforcing braces are placed approximately in the center of the baffle space between baffles and the side walls, and metal end caps close the ends of the baffle space adjacent the intake openings and the discharge openings of the silencers. The baffles are perforated. Typically, the perforations are in the shape of spaced round holes. Any standard perforation pattern, however, may be employed.
When compared to conventional silencers used with Venturi control valves, the closely coupled, packless inlet silencer and the closely coupled packless outlet silencer of the present invention perform as well or better than the less space efficient silencers of the prior art.
Further objects, features and advantages will become apparent upon consideration of the following detailed description of the invention when taken in conjunction with the drawings and the appended claims.
Turning to
As shown in
Perforated baffles 44a, 44b, 44c, and 44d are mounted along the full length of the inside of the inlet silencer 20 by means of intake baffle end caps 56, discharge baffle end caps 58, and intermediate reinforcing braces 48 shown in
Each of the four perforated baffles 44a, 44b, 44c, and 44d may be perforated with one of the illustrative perforation patterns shown in
Table 1 and Table 2 below illustrate the performance of the silencers, either inlet silencer 20 or outlet silencer 30, in accordance with the present invention when closely coupled to a Venturi control valve 12. In the Tables, the silencer 20 or the silencer 30 in accordance with the present invention is designated “J” and is shown in the sketch below Table 2. The other silencers are shown below Table 2 and are designated A-E. The Tables also show the performance of certain competitive silencers designated XYZ. The competitive silencers were closely coupled to the Venturi control valve 12.
Perforated baffles 144a, 144b, 144c, and 144d are mounted along the full length of the inside of the inlet silencer 120 by means of intake baffle rounded end caps 155, discharge baffle end caps 158, and intermediate reinforcing braces 148 shown in
Each of the four perforated baffles 144a, 144b, 144c, and 144d are perforated with one of the perforation patterns shown in
As illustrated herein, the expression “closely coupled” means that the inlet silencer 20 and the outlet silencer 30 are each directly attached to the Venturi control valve 12 without any substantial length of duct without baffles 44 interposed between the Venturi control valve and either the inlet silencer 20 or the outlet silencer 30.
While this invention has been described with reference to preferred embodiments thereof, it is to be understood that variations and modifications can be affected within the spirit and scope of the invention as described herein and as described in the appended claims.
This patent application claims priority from U.S. Provisional Patent Application No. 61/477,858, filed Apr. 21, 2011, which is hereby incorporated by reference.
Number | Date | Country | |
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61477858 | Apr 2011 | US |