The Claims:
1. A vibration test system which comprises:
an enclosure having:
(a) a heat exchange compartment having a circulating fan, a heating device and a cooling device;
(b) a vibration testing compartment having a vibration test system therein for receiving a product to be mounted on a shaker table of the vibration test system for vibration testing; and
(c) a partition between the heat exchange compartment and the vibration testing compartment having at least one gas inlet port and at least one gas outlet port for channeling of gas by action of the circulating fan between the heat exchange compartment and the vibration testing compartment; wherein each inlet and outlet port comprises an entry aperture and an exit aperture and a port wall connecting the port entry aperture and the port exit aperture, wherein the entry aperture is larger than the exit aperture and the wall of the each port forms a duct for passage of gas through the partition, wherein gas circulates between the heat exchange compartment and the vibration testing compartment only through the ports.
2. The test system of claim 1 wherein the wall of each port forms a smooth curve.
3. The test system of any one of claims 1 or 2 wherein the port wall of each inlet and each outlet port forms a bell-shaped curve.
4. The test system of claim 1 wherein the wall of the each port forms a cone or conical shaped curve.
5. The test system of any one of claims 1-4 wherein the entry aperture and exit aperture of both the outlet and inlet ports are circular and the diameter of the entry aperture is larger than the exit aperture of each port.
6. The test system of any one of claims 1-5 further comprising smoothly curving corner baffles at the top corners of the heat exchange compartment.
7. The test system of any one of claims 1-5 further comprising smoothly curving baffles at the intersection of the walls and ceiling in the heat exchanger compartment.
8. The test system of any one of claims 1-7 comprising one central inlet port and an outlet port for each product that can be mounted on the shaker table.
9. The test system of any one of claims 1-8 further comprising flexible hoses connected to the exit aperture of each outlet port for conducting circulating gas to one or more products in the vibration testing compartment.
10. The test system of any one of claims 1-9 wherein the vibration testing compartment is subdivided into a product compartment and a vibration actuator compartment by a flexible diaphragm.
11. The test system of any one of claims 1-10 wherein the partition between the heat exchange compartment and the vibration testing compartment comprises an acoustic absorber.
12. The test system of any one of claims 1-11 further comprising an acoustic absorber layer is provided on at least a portion of each inner wall of the enclosure.
13. The test system of any one of claims 1-12 further comprising an acoustic absorber layer on at least a portion of the inner floor of the enclosure.
14. The test system of any one of claims 1-13 further comprising an external acoustic absorber layer under the floor of the enclosure.
15. The test system of any one of claims 1-14 wherein at least a portion of each wall of the enclosure comprises a layer of acoustical absorber.
16. The test system of any one of claims 1-14 wherein at least a portion of each wall of the enclosure comprises two layers of acoustical absorber separated by a layer of limp vinyl.
17. The test system of claim 16 wherein the acoustical absorber is fiberglass and the two fiberglass layers have different layer thicknesses and fiberglass densities.
18. The test system of any one of claims 1-17 wherein at least a portion of each wall of the enclosure comprises a decoupler layer.
19. The test system of any one of claims 1-17 wherein at least a portion of each wall of the enclosure comprises a vibration damper layer.
20. The test system of any one of claims 1-18 further comprising a door for accessing the vibration testing compartment.
21. The test system of any one of claims 1-19 further comprising a window for viewing the product compartment.
22. The test system of claim 21 wherein the window comprises multiple layers of glass each separated by a spacing compartment.
23. The test system of claim 21 wherein the window comprises a outer glass pane and a plurality of inner glass panes, each of the inner glass panes separated by a spacing compartment and wherein the outer glass pane is separated from the plurality of inner glass panes by a spacing compartment.
24. The test system of claim 21 wherein the window is a multiple layer window consisting essentially of an outer glass pane that is plate glass or laminated glass that is % inch or greater in thickness, and a plurality of inner glass panes that are between λ A inch and 1/8 inch in thickness, each inner glass pane separated by a spacing of 3/8 inch or less and the plurality of inner glass panes separated from the outer glass plane by a spacing of 2-3 inches.
25. The test system of any one of claims 22-24 wherein the spacing compartments separating the glass panes are filled with a gas selected from dry nitrogen or argon or the spacing compartments are evacuated.
26. The test system of any one of claims 1-25 wherein the fan is a forward inclined fan.
27. The test system of any one of claims 1-25 wherein the fan is a backward inclined fan.
28. The test system of any one of claims 1-27 wherein the air inlet of the fan is aligned with the circulating gas input port.
29. The test system of any one of claims 1-27 comprising more than one circulating fan wherein each circulating fan is aligned with a circulating gas input port.
30. The test system of any one of claims 1-27 wherein the heating devices, cooling device or both are positioned with respect to the circulating fan or fans such that gas circulated by the fan or fans contacts a heating device, cooling device or both prior to exiting the heat exchange compartment through any outlet port. |
VIBRATION TEST SYSTEM ENCLOSURE
BACKGROUND OF THE INVENTION
[0001] This invention relates to enclosures for vibration test systems that provide for efficient heat exchange and gas (e.g., air) circulation within the enclosure. The enclosures are particularly useful for use in testing that incorporates and combines thermal cycling, thermal shock and other types of thermal testing of products with vibrational testing. The enclosures and heat exchange system of this invention can be combined with various art-known vibration systems that are used to test the vibration resilience of products. Test engineers can employ the enclosure of this invention in combination with such vibration systems to emulate the environment(s) that a product will encounter or to precipitate and detect flaws in a product that could cause failures in the field. The enclosure is provided with appropriate thermal insulation. Additionally the enclosure of this invention provides acoustic absorption to provide significant reductions in emitted noise levels during operation of vibration test systems.
[0002] The present invention can be employed in general with any vibrational testing system and in particular with any vibrational testing system that incorporates one or more shaker tables which are used to emulate vibrations encountered by a product (i.e., product under test). A basic shaker table includes a platform upon which the product is mounted. The platform is supported on flexible supports that permit the vibration of the table freely in all directions, independent of the environment. The shaker table generates vibration in multiple axes (e.g., six axes) by providing either electrically driven, pneumatically driven, hydraulically driven, or mechanically driven actuators, or combinations thereof, termed exciters or vibrators that produce an impact or other force shape to initiate the vibrations. The platform couples the vibrations from the actuators to the product. The typical actuator is a device that produces forces of high magnitude, but very short duration. Short duration, high magnitude pulses in the time domain translate into broadband vibration spectra in the frequency domain. Thus, actuators provide the input vibration stimulus for use by the shaker table in the desired manner. The physical properties of the shaker table components cause the shaker table to re-
spond to the different frequencies in the impact spectrum in different ways. The physical properties of the shaker table components typically resonate with certain vibration frequencies and suppress other vibration frequencies to result in selected modes of vibration. For example, resonation results in the vibrations remaining for a relatively long time compared to the duration of the input pulse, while suppression results in the quenching of the vibration in a relatively short time. The modes of vibration of the shaker table are also a function of the location, orientation and nature of the actuators as well as the dimensions and properties of the platform.
[0003] In specific embodiments, the vibration test system enclosure and heat exchange system of this invention can be employed with a vibration test system such as those described in U.S. patent 5,979,242. Additional vibration test systems and portions thereof that can be employed with the enclosure and heat exchange of this invention include without limitation those described in U.S. patents 3,369,393; 3, 686, 927; 4,164,151; 4,181,028; 4,181,028; 4, 735, 089; 5,365,788; 5,412,991; 5,969,256; 6,422,083; and 6,502,464, as well as vibration test systems employing one or more shaker tables that are currently commercially available or in commercial use. (See U.S. patent 5,979,242, for examples).
[0004] U.S. patent 6,863,123 relates to a high thermal change rate test apparatus having a cabinet body containing electric heaters and liquid nitrogen pipes and valves and a plurality of circulating fans to form a downward blowing air flow for rapid air circulation in the cabinet.
[0005] U.S. patent 6,446,508 relates to environmental control of a vibration compartment. A vibration testing cabinet is described to define a testing chamber and a vibration chamber. Heating and cooling elements are provided in the test chamber and in the vibration chamber.
[0006] U.S. patents 5,540,109 and 5,675,098 relate to apparatus for environmental screening of products. The apparatus has a number of screening compartments to subject products to differing environmental and functional conditions. In a compartment, products can be simultaneously subjected to vibrational
and temperature conditions. Products are transported between screening compartments via a conveyor system. A screening compartment can be provided with heating and/or cooling devices and a circulating fan. Each compartment can be provided with corner baffles and a channeling baffle to control exchange of thermal energy with the products being screened.
[0007] U.S. Reissued patent Re. 32, 933 (reissue of U.S. patent 4,572,283) relates to an environmental test chamber which provides for selective heating or cooling of the chamber. Heating coils are provided in a first duct communicating with the chamber and refrigeration coils are provided in a second duct communicating with the chamber. A damper is provided for closing the second duct when the heating coils are in operation. A fan draws air from the first duct into the chamber. A flexible boot extends from the first duct to direct air onto the object under test.
[0008] Problems associated with temperature control in vibration testing systems include inefficient gas circulation which can lead to non-uniform temperatures or increased time for achieving stable, uniform temperatures or which require the use of heavy high power circulating fans to achieve sufficient gas flow for uniform and stable temperature control. Additionally, vibration testing equipment generates high noise levels in the surrounding environment requiring the use of noise protection by personnel in the vicinity when the equipment is in operation. The vibrational test system enclosure of the present invention provides improved efficiency of gas circulation throughout the enclosure facilitating more rapid temperature stabilization and more rapid temperature cycling in the system. Additionally, the enclosure of the present invention provides for significant beneficial reductions in noise levels in the vicinity of vibrational test systems.
SUMMARY OF THE INVENTION
[0009] The invention provides a vibration test system which comprises a enclosure which is preferably thermally insulated and/or provided with acoustic absorption elements. The enclosure comprises a heat exchange compartment and a vibration testing compartment which in turn can be subdivided into a product compartment and a vibration actuator compartment. The heat exchanger com-
partment is separated from the vibration testing compartment by a partition having inlet and outlet ports to facilitate gas circulation between the two compartments. The heat exchanger compartment comprises a circulating fan, a heating device and/or a cooling device. The vibration test compartment comprises a vibration test system therein for receiving a product to be mounted on a shaker table of the vibration test system for vibration testing. The partition between the compartments comprises at least one gas inlet port and at least one gas outlet port for channeling or direction of gas by action of the circulating fan between the heat exchange compartment and the vibration testing compartment.
[00010] Each inlet and outlet port comprises an entry aperture and an exit aperture and a port wall connecting the port entry aperture and the port exit aperture to form a duct for passage of circulating gas. The entry aperture is larger than the exit aperture. In a specific embodiment, the duct formed by wall of the port does not contain any constrictions to inhibit gas flow and the duct (e.g., expanse or diameter) is generally larger than the exit aperture along its length. In a specific preferred embodiment, the exit aperture is flared to provide an exit aperture that is larger (e.g., 10-20% larger) than the adjacent end of the duct. The inlet and outlet ports are the only apertures provided in the partition for gas circulation between the heat exchange compartment and the vibration testing compartment.
[00011] In specific embodiments, the wall of an inlet or outlet port forms a smooth curve. In more specific embodiments, the wall of an inlet or outlet port forms a bell-shaped curve. In specific embodiments, the wall of an inlet or outlet port forms a cone or conical-shaped curve. The entry aperture and exit aperture of the port can be any shape, but in specific embodiments both the outlet and inlet ports are circular and the diameter of the entry aperture is larger than the diameter of the exit aperture. In preferred embodiments, the inlet and outlet ports, including the duct of the ports, do not have any corners which would inhibit or impede passage of gas through the ports.
[00012] In a specific embodiment the test system further comprises smoothly curving corner baffles at the top corners of the heat exchange compartment. These baffles function to enhance efficient air flow through the inlet and outlet
ports of the partition. Alternatively, the test system further comprises smoothly curving baffles at the intersection one or more walls and ceiling in the heat exchanger compartment.
[00013] In a specific embodiment, the heat exchange compartment comprising one central inlet port and an outlet port for each product that can be mounted on the shaker table in the vibration testing compartment.
[00014] In a specific embodiment, flexible hoses are connected to the exit aperture of each outlet port for conducting circulating gas to one or more products in the vibration testing compartment.
[00015] In specific embodiments, the partition between the heat exchange compartment and the vibration testing compartment comprises an acoustic absorber. In this embodiment, the partition comprises a top and a bottom partition wall forming a chamber into which the acoustic absorber is introduced. The top partition wall contains inlet port exit apertures and outlet port entry apertures. The bottom partition wall contains inlet port entry apertures and outlet port exit apertures. When an acoustic absorber is provided in the partition chamber, the bottom partition wall additional contains a plurality of apertures to allow sound to enter into the absorber. Again in this embodiment, the inlet and outlet ports are the only means provided for gas circulation between the heat exchange compartment and the vibrations testing compartment.
[00016] An acoustic absorber layer is optionally provided on at least a portion of each inner wall of the enclosure and optionally on the inner floor of the enclosure. In specific embodiments, acoustic absorption layer is provided on any inner wall or floor surface where the layer does not interfere with gas circulation or the operation of other device elements. Acoustic absorption layers can optionally be provided on any door or access panel that may be provided in the enclosure. IN a specific embodiment, an external acoustic absorber layer can be provided under the floor of the enclosure. In a specific embodiment, a skirt comprising an acoustic absorber can be provided around the circumference of the enclosure at the bottom of the enclosure.
[00017] Acoustic absorber layers can optionally be combined with vibration clamping layers, barrier layers and/or decoupling layers at all locations where acoustic layers alone are optionally provided.
[00018] In specific embodiments, walls (ceilings and floors) of the enclosure optionally comprise one or more layers of acoustic absorber and/or thermal insulation. In specific embodiments, fiberglass layers are provided for acoustic absorption and/or thermal insulation. In specific embodiments, walls (ceilings and floors) of the enclosure comprise two layers of acoustical absorber which are optionally separated by a layer of limp vinyl. The two layers of acoustical absorber can be fiberglass and the two fiberglass layers can have different layer thicknesses and fiberglass densities. The walls (ceilings and floors) of the enclosure can further comprise one or more decoupler layers. The walls (ceilings and floors) of the enclosure can further optionally comprise one or more vibration damper layers.
[00019] The test system is optionally provided with a door for accessing the vibration testing compartment and/or a window for viewing the product compartment. Additionally the test system may be provided with access panels for accessing compartment of the enclosure. Doors and panels can be provided with one or more acoustic absorber layers, thermal insulation layers, vibration damping layers, decoupling layers, and or barrier layers.
[00020] The optional window can comprise multiple layers of glass each separated by a spacing compartment. In a specific embodiment the window comprises a outer glass pane and a plurality of inner glass panes, each of the inner glass panes separated by a spacing compartment and wherein the outer glass pane is separated from the plurality of inner glass panes by a spacing compartment. In a more specific embodiment, the window is a multiple layer window consisting essentially of an outer glass pane that is plate glass or laminated glass that is % inch or greater in thickness, and a plurality of inner glass panes that are between % inch and 1/8 inch in thickness, each inner glass pane separated by a spacing of 3/8 inch or less and the plurality of inner glass panes separated from the outer glass plane by a spacing of 2-3 inches. The spacing compartments
separating the glass panes of the window can be filled with a gas selected from dry nitrogen or argon or the spacing compartments can be evacuated.
BRIEF DESCRIPTION OF THE DRAWINGS
[00021] Figure 1 is a plan view (from above the compartment) of the interior of a forced-air heat exchange compartment of an exemplary vibration testing system enclosure of this invention illustrating the relative locations of the fan, heating and cooling elements and gas inlet and outlet ports.
[00022] Figure 2 is a cross-sectional side view of the heat exchanger compartment and the vibrational testing compartment of a vibrational test system enclosure of the invention illustrating a shaker table with products under test and a vibration actuator system mounted in the enclosure. Gas circulation from the heat exchange compartment into the vibration testing compartment is illustrated. A bell-shaped gas inlet port for circulation of gas (e.g., air) into the heat exchanger compartment is shown.
[00023] Figures 3A and 3B illustrates exemplary alternative curved or conical inlet and outlet port shapes for efficient gas circulation in the heat exchanger system of the enclosure of this invention.
[00024] Figures 4A-D illustrate additional exemplary alternative inlet and outlet port shapes useful for efficient gas circulation in the heat the heat exchanger system of the enclosure of this invention. Figures 4E and 4F illustrate inlet and outlet port shapes that are not suitable for efficient gas circulation in the heat the heat exchanger system of the enclosure of this invention.
[00025] Figure 5A is a cross-sectional side view of an additional exemplary vibration testing enclosure of this invention combining acoustic insulation with improved gas circulation.
[00026] Figure 5B is a plan view of the top of partition 30 showing the inlet and outlet ports for efficient gas circulation in the enclosure of Figure 5A.
[00027] Figure 6 is a detailed cross-sectional view of a preferred thermal and acoustic insulating core of the insulating walls, floor, and ceiling portions of an enclosure of this invention. This detail can also be provided in any door or access port into the enclosure.
[00028] Figure 7 is a detailed cross-sectional view of a preferred window configuration for use in the enclosures of this invention. This configuration provides for additional acoustic insulation. The illustration is not drawn to scale and only a portion of gas space 46 is shown.
DETAILED DESCRIPTION OF THE INVENTION
[00029] The invention is described by reference to the Figures attached hereto in which like numbers represent like elements. The Figures represent exemplary embodiments of the invention and it will be clear to one of ordinary skill in the art that device elements other than those specifically described can be employed in the practice of the invention.
[00030] Figure 1 is a plan view of the interior of a forced-air heat exchange compartment 1. Figure 2 is a cross-sectional side view of heat exchange compartment 1 combined with a vibration test system compartment. Referring to Figs. 1 and 2, the heat exchange compartment comprises a preferably thermally insulated enclosure defined by a floor (alternatively called a partition) 3, thermally insulating walls 4, and thermally insulating ceiling 5. The enclosure contains a circulating fan 6 surrounded by an array of heating elements 7, cooling elements, such as liquid nitrogen injector nozzles 8, or a refrigeration evaporator 9 or any combination of heating and cooling elements. The number and position of heating elements or cooling elements is preferably selected such that circulating gas (e.g., typically air or a mixture of air and nitrogen) passing from the fan is heated or cooled as desired. Partition 3 comprises a bell-shaped entry port 10 opening through the partition, aligned with the fan, delivery entering gas to the fan. The floor also comprises a number (more than one and preferably one for each specimen under test) of bell-shaped exit ports 11 and 12 opening from the heat exchange compartment (1) through the partition to the vibration testing compartment (2).
[00031] The fan can be driven by an internal motor (not shown) or by a shaft or belt arrangement coupled to an external motor (also not shown). Liquid nitrogen supply lines and electrical connections are also provided, but are not shown. As will be shown below, the system can be provided with a utility compartment above the heat exchange compartment, for housing the fan motor. This compartment optionally contains liquid nitrogen supply lines, and various electrical connections for heating and cooling devices. The utility compartment is vented and may be provided with one or more fans to provide appropriate air circulation to avoid overheating of the motor or fan shaft which operably links the fan and the motor. The utility compartment is typically provided (for housing the fan motor among other devices) with a removable access panel.
[00032] The enclosure can be provided with a door or one or more removable access panels for accessing the product compartment (preferably a door), the heat exchange compartment and/or the vibration actuator compartment (preferably access panels) and any utility compartment.
[00033] Again as discussed in more detail below, the walls, ceiling, floors, any doors and access panels can be provided with provided with thermal insulation, acoustic absorber layers, decoupling layers, barrier layers, vibration damping layers or the multiple layer acoustic absorption system as illustrated in Figure 6. [00034] In a specific embodiment the enclosure of this invention comprises a frame to support the walls, ceiling and floor of the enclosure and to provide support for attachment of internal features (partitions, flexible diaphragm, etc.). In a more specific embodiment, the frame is formed from stainless steel tubing (round or rectangular tubing). Preferably the frame tubing is filed with an acoustic absorber material, such as fiber glass to dampen vibrations and decrease noise emission by the enclosure when the vibration testing system is in operation. [00035] Although fan (6) is depicted as a centrifugal fan in the drawing, it can also have different forms such as, radial fans and various types of axial-flow fans. The fans may be forward inclined fans or backward inclined fans. In a preferred embodiment, the fan is forward inclined fan rather than a backward inclined fan. Forward inclined fans are generally lighter in weight and have lower power requirements than backward inclined fans. Forward inclined fans typically generate moderate flow in comparison to backward inclined fans (high flow rates). The higher flow rate, higher power backward inclined fans have typically been used in
test systems to achieved high desired gas circulation for efficient heat exchange. The efficient gas circulation systems in the heat exchange compartments of this invention allow the use of the more moderate flow, lighter weight, lower power, lower cost, forward inclined fans.
[00036] In a typical application, the heat exchange compartment is mounted on, or connected to, the vibration test system compartment 2 comprising a preferably open-topped cabinet having a space 14 defined by insulating walls 16 and an optional insulated floor 17. In this case a means for mounting and sealing the two compartments is provided. However, as would be understood by one of ordinary skill in the art, the enclosures for the heat exchanger 1 and the test system 2 can have many various sizes, shapes and separation points, as well as being enclosed in a single cabinet with a rigid or flexible membrane separating the exchanger function from the test system. In an embodiment, the vibration test system compartment (2) is subdivided into a product compartment (2a) and a vibration actuator compartment (2b) by flexible diaphragm 18. [00037] The test system typically contains a shaker table 15 mounted on, or coupled to, a vibrating actuator system 19. The flexible diaphragm 18 seals the space above the table from the space below the table and thereby protects the actuator system from temperature extremes. A number of specimens (i.e., products under test) 20 are mounted on, or coupled to, the shaker table and located under or near their corresponding exit ports 11 and 12. Specimens 20 are preferably coupled to their respective exit ports by flexible hoses 13. The number of specimens under test can be chosen to match the number of exit ports or, conversely, the number of open ports can be chosen to match the number of specimens by closing some of the ports -- within the limits of the minimum gas flow requirements. The entry and exit ports provide for all circulation of circulating gas between the vibration testing compartment (or more specifically the product compartment) and the heat exchange compartment. No additional openings, vents or perforations are provided in partition 3 for circulation of gas. [00038] To avoid over pressurization of the enclosure above ambient pressure, an over pressure vent (not shown) can be provided in the vibration testing compartment, typically in the product compartment for releasing gas from the system. The vent is provided a pressure responsive valve, such as a flapper valve, that opens in response to above ambient pressure in the enclosure and closes when
the overpressure is released. The vent conveys excess gas out of the system and preferably to a location external to any building housing the system. The vent is preferably provided with a muffler, typically a fiber glass muffler, to provide sound absorption. Over pressurization of the enclosure can occur when liquid nitrogen is sprayed into the heat exchange compartment to provide for cooling. [00039] It will be appreciated that a heat exchange system of this invention can include more than one fan and more than one entry port and can be adapted for use in combination with multiple vibration testing systems. [00040] In operation, gas (typically air) is drawn from space 14 through inlet port 10, into fan 6 where it is accelerated by the fan and blown past heating elements 7, injectors 8 and evaporator 9. The air is heated by passing over elements 7 or cooled by the evaporation of liquid nitrogen or by the refrigeration evaporator, as appropriate, and exits the heat exchanger through outlet ports 11 and 12. The air flows through the flexible hoses and across the specimens thereby transferring heat to or from the specimens. Then, the air diffuses into space 14 and is drawn back into the exchanger to repeat the described gas circulation cycle.
[00041] A major advantage of the heat exchanger system of this invention is the use of inlet ports and outlet ports in which the entry aperture of the port is larger than the exit aperture of the port to provide for efficient gas flow through the ports. The ports comprise a wall which extends between the entry and exit apertures forming a duct for passage of gas. In preferred embodiments, the inlet and outlet ports are bell-shaped or conical in shape. In alternative embodiments the inlet and outlet ports are cone shaped. The walls of the inlet and outlet ports preferably present a smoothly curving surface which facilitates rather than impedes or inhibits gas passage through the port.
[00042] Inlet and outlet ports are arranged in such a way that relatively calm, i.e., low-turbulence, gas (e.g., air) is drawn into the larger entry ends of the ports and accelerated as it passes through the generally decreasing cross-sectional area of the duct of the ports (to the exit aperture). Exemplary ports are illustrated in more detail in Figures 3A and 3B. Figure 3A shows the bell shapes of port 10, inverted, and of ports 11 and 12. Figure 3B shows an alternate conical shape of port 10, inverted, and ports 11 and 12. The larger diameter, entry apertures of
the ports are indicated in Figs. 1 , 3A-B, and 5B by the numerals 1 OA, 11A and 12A. The smaller, exit apertures are indicated in Figs. 1 , 3A-B and 5B by the numerals 10B, 11B and 12B. The conical port shown in Fig. 3B can have multiple sections: for example, three sections comprising a first conical section 21 , a second conical section 22 and straight section 23, as shown, or a simpler version comprising only the first section adapted and connected directly to the straight section.
[00043] Ports as shown in Figs. 4A-D, having bell-shaped or conical duct shapes have air flow entry losses of about 5%-7% of velocity pressure, while ports with sharp (e.g., right angle) entry corners, as in Figs. 4E-F have entry losses of 50% for flanged pipes and 90% for unflanged pipes (See: Cincinnati Fan Catalog (Engineering Data) #ENG-203, page 10). Although the ports of Figs. 3A are shown with smooth bell curves, only slightly increased losses can be obtained with one simple cone or two sequential cones as shown in Fig.3B. And, as in the case of ports 1 1 (Figure 2), truncating a portion of the entry portion of ports placed near or against the walls of the exchanger produces minimal increases in entry losses.
[00044] Heat exchange systems of this invention can be used for heating, cooling, or both heating and cooling dependent upon the choice of elements 7, 8 and 9 included in the device. In a specific embodiment, the heat exchange system comprises all of elements 7, 8 and 9 and can be used for heating, cooling, or both heating or cooling by activating and deactivating, as appropriate, the heating and cooling elements. The heating elements can, for example, be electrical resistive types and the cooling elements can, for example, be refrigeration coils or, preferably, injectors for liquid nitrogen (or other appropriate coolant) or both. By suddenly switching between heating and cooling, or vice versa, the exchanger can provide thermal shocks to the specimens, either statically or dynamically while the specimens are being vibrated. In preferred embodiments, heating coils are used in which the loops of the coil are sufficiently separated to allow efficient gas (e.g., air) circulation to the coil and efficient heat transfer from the coil to the circulating gas.
For greater efficiency, although slower in response, the heating and cooling functions can be provided by a heat pump utilizing the previously described evaporator 9 alternately as a condenser [24] for heating and as an evaporator 9 for cooling.
Figures 5A and 5B illustrate an alternative vibration test system of this invention having an enclosure 100 comprising a heat exchange compartment 1 , a product compartment 2a, a vibration actuator compartment 2b and a utility compartment (27). The components of the heat exchange compartment, product compartment and vibration actuator compartment are analogous to those illustrated in Figures 1 and 2 and discussed above. As in Figures 1 and 2, a partition (30) is provided which is forms inlet ports 10 and outlet ports 11.
[00045] In the illustrated system, the partition 30 between the heat exchange compartment and the product compartment comprises a top 61 and a bottom 62 partition wall forming a chamber into which acoustic absorber 63 can be introduced. As illustrated in Figure 5B, the top partition wall contains inlet port exit apertures 10b and outlet port entry apertures 11a. The bottom partition wall 62 contains inlet port entry apertures 10a and outlet port exit apertures 11 b. When an acoustic absorber is provided in the partition chamber, the bottom partition wall additional contains a plurality of apertures (not shown) to allow sound to enter into the absorber. Again in this embodiment, the inlet and outlet ports are the only means provided for gas circulation between the heat exchange compartment and the vibrations testing compartment.
[00046] The top wall 61 forming the partition can be substantially flat across its surface. Alternatively, as illustrated, for example, in dashed lines, top wall 61 may be curved upward at the exit aperture of the inlet port to facilitate delivery of circulating gas to fan 6. In another alternative, which is not specifically illustrated in the figure, the exit aperture of the inlet port can be flared to facilitate curving or expansion of the exiting gas along the fan. In all cases, it is preferred that any structure in the top or bottom walls of the partition presents a smoothly curving surface to gas flow to facilitate efficient gas circulation.
[00047] The heat exchange compartment is optionally, but preferably provided with smoothly curving baffles 60 which further facilitate efficient gas circulation between the heat exchange compartment and the product compartment. These baffles may be provided in one or more of the corners formed between the walls and ceiling of the compartment or may be formed along the entire length of the intersection between the walls and the ceiling of the compartment. The enclosure is optionally provided with a door and/or access panels as discussed above. The enclosure may be formed by mounting the heat exchange compartment on the product compartment and providing a seal (41).
[00048] The utility compartment 27 is formed by walls 29, ceiling 28 and thermally insulated ceiling 5 of the heat exchange compartment 5. The utility compartment houses the fan motor as well as required electrical connections and can further contain supply lines for liquid nitrogen. The utility compartment optionally contains a fan to remove heat from the compartment generated by the motor or generated in the heat exchange compartment. It is particularly beneficial to remove heat from the fan shaft and more particularly from the bearing in that shaft. One or more fans can be provided to circulate gas (typically ambient outside air) through the compartment. Other means for removing heat from the compartment and particularly from the fan shaft can be provided, for example, the shaft can be provided with a heat slinger device. Typically one or more air in-takes or vents are provided in the utility compartment.
[00049] As described above, the product compartment can be provided with a vent and appropriate pressure responsive valve to avoid over pressurization of the enclosure.
[00050] Figure 6 illustrates a preferred wall configuration for use in any of the walls, ceilings, floors, doors, and access panels of the enclosure. The multiple layer configuration comprises an inner skin (51) and an outer skin (57). The inner skin is preferably stainless steel and the outer skin can be any appropriate material having sufficient mechanical strength to form the wall, including, but not limited to stainless steel, carbon steel, or fiber glass sheets. The wall configuration is provided with at least one and preferably two layers (52 and 54) of acoustic
absorber material (this material will also provide for thermal insulation). A preferred acoustic absorber material is fiber glass. When two layers are provided the layers are separated by a barrier layer 53 which in a specific embodiment is limp vinyl. In a specific embodiment, a first inner absorber layer (52) is thinner than a second outer (54) absorber layer and the densities of the absorber materials) employed may be different. In a specific embodiment, the outer absorber layer en has a higher density than the inner absorber layer. Additionally, a decoupling layer (55) which is for example a layer of foam is provided separated from absorber layer 52 or 54 by a second barrier layer 53. Additionally, a vibration damping layer can be provided 56 adjacent to and outward from the decoupling layer. The use of this wall configuration in any of the walls, ceiling, floor, doors or panels of the enclosure provides for significantly reduced noise emission from the vibration testing system.
[00051] In a specific embodiment of Figure 6 in which fiber glass is employed as the absorbing layers (52 and 54), a thinner inner layer (1 inch thick of 3lb/square foot fiberglass) is combined with a thicker outer layer (2 inch thick of 6 Ib/square inch fiber glass).
[00052] Figure 7 illustrates a preferred window configuration for use in the optional window of the enclosure. This window configuration provides for decreased noise emission from the system and can further provide improved thermal insulation at the window. The window preferably comprises multiple layers of glass (45 or 47) each separated by a spacing compartment (46 or 48).
[00053] As illustrated in Figure 7, an outer glass pane 45 and a plurality of inner glass panes 47 form the multiple layer window. Each of the inner glass panes is separated by a spacing compartment 48 (three glass panes are exemplified) and the outer glass pane (45) is separated from the outermost of the plurality of inner glass panes by a spacing compartment (46). Typically the outer glass pane is plate glass or a laminated glass (such as is used in car windshields) and the outer glass pane is thicker than the inner glass panes. Further the spacing compartment (46) between the outer glass and the plurality of inner glass panes is
typically thicker and preferably much thicker (for example from 5 to 10 times thicker) than the spacing compartment that separates the inner glass panes (48).
[00054] In a specific embodiment the outer glass pane (45) is plate glass or laminated glass that is % inch or greater in thickness, and a plurality of inner glass panes that are between % inch and 1/8 inch in thickness, each inner glass pane separated by a spacing of Vz inch or less or more preferably 3/8 inch or less and the plurality of inner glass panes separated from the outer glass plane by a spacing of, 1 to 4 inches and more specifically from 2-3 inches.
[00055] The spacing compartments in the windows are filled with a gas selected from dry nitrogen or argon (or dry air) or the spacing compartments are evacuated. If one or more of the spacing of the window are to be evacuated, a valve can be provided into the compartment for selective application of a vacuum pump (or other source of vacuum) to provide evacuation. A similar valve can be provided to introduce a desired gaseous atmosphere to the compartment.
[00056] Technical terms employed herein are intended to have there broadest art-recognized meaning that is consistent with the entire description herein and the context of the use of such terms herein.
[00057] The invention further provides methods for combined vibrational and thermal testing of specimens or products employing a vibration test enclosure with heat exchange system of this invention in combination with a vibrational testing system. In particular, the methods of this invention provide for combined vibrational and thermal shock testing. In specific embodiments, the methods herein employ a vibrational test system of U.S. patent 5,979,242 which may be implemented with a variety of vibrational actuators. U.S. provisional application 60/803,491 , filed May 30, 2007 entitled 'Heat Exchanger for Vibration Test System," is incorporated by reference herein in its entirety.
[00058] When a Markush group or other grouping is used herein, all individual members of the group and all combinations and possible subcombinations of the group are intended to be individually included in the disclosure. Every combination of components described or exemplified herein can be used to practice the invention, unless otherwise stated. One of ordinary skill in the art will appreciate
that methods, device elements, and materials other than those specifically exemplified can be employed in the practice of the invention without resort to undue experimentation. All art-known functional equivalents, of any such methods, device elements, and materials are intended to be included in this invention. Whenever a range is given in the specification, for example, a temperature range, a frequency range, a time range, or a composition range, all intermediate ranges and all subranges, as well as, all individual values included in the ranges given are intended to be included in the disclosure. Any one or more individual members of a range or group disclosed herein can be excluded from a claim of this invention. The invention illustratively described herein may be practiced in the absence of any element or elements, limitation or limitations which is not specifically disclosed herein.
[00059] As used herein, "comprising" is synonymous with "including," "containing," or "characterized by," and is inclusive or open-ended and does not exclude additional, unrecited elements or method steps. As used herein, "consisting of excludes any element, step, or ingredient not specified in the claim element. As used herein, "consisting essentially of does not exclude materials or steps that do not materially affect the basic and novel characteristics of the claim. Any recitation herein of the term "comprising", particularly in a description of components of a composition or in a description of elements of a device, can be exchanged with "consisting essentially of or "consisting of.
[00060] Although the description herein contains many specificities, these should not be construed as limiting the scope of the invention, but as merely providing illustrations of some of the embodiments of the invention. Each reference cited herein is hereby incorporated by reference in its entirety. However, if any inconsistency arises between a cited reference and the present disclosure, the present disclosure takes precedent. Some references provided herein are incorporated by reference to provide details concerning the state of the art prior to the filing of this application; other references may be cited to provide additional or alternative device elements, additional or alternative materials, and additional or alternative methods of analysis or application of the invention. All patents and publications mentioned in the specification are indicative of the levels of skill of
those skilled in the art to which the invention pertains. References cited herein are incorporated by reference herein in their entirety to indicate the state of the art as of their publication or filing date and it is intended that this information can be employed herein, if needed, to exclude specific embodiments that are in the prior art. One of ordinary skill in the art will appreciate that device elements, as well as materials, shapes and dimensions of device elements, as well as methods other than those specifically exemplified can be employed in the practice of the invention without resort to undue experimentation. All art-known functional equivalents, of any such materials and methods are intended to be included in this invention. The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention that in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. Thus, it should be understood that although the present invention has been specifically disclosed by preferred embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention.