Rotary kinetic fluid motors or pumps – With sound or vibratory wave absorbing or preventing means...
Reexamination Certificate
2002-11-21
2004-10-12
Look, Edward K. (Department: 3745)
Rotary kinetic fluid motors or pumps
With sound or vibratory wave absorbing or preventing means...
C415S183000, C415S208100, C181S224000, C239S265130, C138S037000
Reexamination Certificate
active
06802690
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to air duct outlet silencers, and in particular to silencers designed for use with gas turbines and other noise-creating, gas flow-producing devices.
Stationary gas turbines for the production of power are well known for use by power producing industries. One difficulty that is encountered with the use of gas turbines is the noise that they can create during their operation. Because of this noise, efforts have been made in the past to provide sound attenuators or sound reducing devices both at the intake of the gas turbine and at the outlet end. However for various reasons problems have been encountered in developing satisfactory inlet silencing units and outlet silencing devices for these gas turbines. One reason for these difficulties is that the flow into and out of stationary gas turbines is often compromised because of spacial constraints and cost factors. Many such systems feature a short plenum box with a vertical inflow into the compressor of the turbine and an axial outflow. In the usual case, inlet silencers are installed ahead of the plenum while the gas turbine outlet is often dumped into a plenum which feeds a vertical exhaust section consisting of some form of silencer and exhaust stack.
Outside of the field of gas turbines, both air duct inlet silencers and air duct outlet silencers have been developed in recent years for use in combination with axial fans providing air to large structures such as office buildings and industrial buildings. For example U.S. Pat. No. 5,587,563 issued Dec. 24, 1996 to Dipti K. R. Datta describes both an air inlet silencer for an axial fan and an air outlet silencer, both of which employ sound attenuating material located behind perforated sheet metal walls. The duct inlet silencer includes an exterior housing that has two principal air inlets located on opposite sides of the housing. The unit also has a single air outlet located at one end of the housing. The two inlets and the outlet are connected by airflow passageways defined by interior walls and these passageways bend 90 degrees from the inlets to the outlet. Sections of the interior walls are made from the aforementioned perforated sheet metal. In one preferred embodiment the passageway from each inlet is divided into four quadrants with upper and lower quadrants separated by a horizontal divider.
With respect to the fan outlet silencer described in the aforementioned U.S. patent, it has a top, bottom, and sidewalls and between these walls extend first and second series of splitters with the splitters of each series being spaced apart to form smaller air passageways. The splitters of each series are mounted side by side in a row and the splitters of one series are staggered with respect to the splitters of the other series in a direction transverse to the direction of airflow. The sound attenuating material that is used in both the inlet silencer and the outlet silencer for an axial fan as described in this U.S. patent is standard sound attenuating material such as fibreglass bats stuffed between the interior walls and the exterior walls and into the interior of the splitters.
Up to the present time, there has been no suggestion that inlet and outlet silencers of this general type could be used in combination with relatively large, stationary gas turbines. One difficulty with the known outlet silencers designed for use with ordinary axial fans is that they are not able to withstand the high temperatures that exist in the hot air stream emitted by the gas turbine nor are they able to withstand the much higher air velocities which can be as much as 15000 feet/minute and higher.
In the air handling art wherein systems have been developed for providing fresh air and return air to structures using suitable fans, it is known that turning vanes to redirect the direction of the airflow into or out of a fan unit can provide excellent turning performance including uniform airflow with minimum pressure loss. The use of such turning vanes in combination with sound attenuating material has proven to be effective in air supplying and air conditioning applications involving the use of axial fan units. Most of these systems employ conventional acoustic dissipative media such as fibreglass. In many of these recently developed systems the sound absorbing surface comprises a special sandwich construction consisting of a perforated cover sheet, an erosion resistant duct-liner and bulk fibre located behind the duct liner and packed to the proper density. However as far as applicant is aware, this sound attenuating technology has in general not been used with nor proposed for use with gas turbines such as large, stationary gas turbines used for the production of power.
It is an object of the present invention to provide a novel sound attenuating duct unit suitable for connection to the outlet of a stationary gas turbine or other noise-creating, gas flow-producing device, this unit being capable of manufacture at a reasonable cost while having substantial sound attenuating capabilities.
SUMMARY OF THE INVENTION
According to one aspect of the invention, a sound attenuating duct unit suitable for connecting to an outlet of a stationary gas turbine includes a housing having a horizontal housing section and a vertical housing section and having sidewalls surrounding a main airflow passageway that extends along a substantial bend. An air inlet is located at one end of the horizontal housing section and is adapted for connection to the outlet of the gas turbine. At least one air outlet is located at least proximate to an upper end of the vertical housing section. At least two splitters are mounted in the housing. The splitters divide sections of the main airflow passageway into smaller air passageways. At least one of the at least two splitters is positioned downstream in the main airflow passageway relative to at least another of the at least two splitters. The at least two splitters contain sound attenuating material selected from a group of materials comprising ceramic fibers and mineral wool and capable of withstanding airflow temperatures in the main airflow passageway of at least 500 degrees Celsius. The at least two splitters each contain a fine metal screen having 200 or more strands per inch and covering the sound attenuating material. The metal screen is provided to prevent the sound attenuating material from escaping the splitters. At least a substantial portion of both the sidewalls surrounding the main airflow passageway and metal sidewalls forming the splitters are made of perforated sheet metal having a thickness of at least 12 gauge.
In one embodiment of this outlet silencer for a turbine, the perforated sheet metal is made of stainless steel.
According to another aspect of the invention, there is provided a combination of a gas turbine intended for installation and use at a selected stationary site and a sound attenuating duct unit connected to a hot air exhaust outlet of the gas turbine. The duct unit includes a housing having a horizontal housing section and a vertical housing section and having sidewalls surrounding a main airflow passageway that extends along a substantial bend. There is an air inlet located at one end of the horizontal housing section and connected to the exhaust outlet of the gas turbine. At least one air outlet is located at least proximate to an upper end of the vertical housing section. The combination also includes at least two splitters mounted in the housing. The splitters divide sections of the main airflow passageway into smaller air passageways. At least one of the at least two splitters is positioned downstream in the main airflow passageway relative to at least another of the at least two splitters. The splitters contain sound attenuating material selected from a group of materials comprising mineral wool and ceramic fibers and capable of withstanding airflow temperatures in the main airflow passageway of at least 500 degrees Celsius. A layer of fine stainless steel screen having 200 or more strands per
Han Ming Hui
Yazici Muammer
M & I Heat Transfer Products Ltd.
McAleenan J. M.
Young & Basile P.C.
LandOfFree
Outlet silencer structures for turbine does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Outlet silencer structures for turbine, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Outlet silencer structures for turbine will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3315588