Patent Grant
8753564
The present disclosure relates to seal devices used in pneumatic control systems for operating metal processing baths.
This section provides background information related to the present disclosure which is not necessarily prior art.
Known systems used to control operations of metal processing baths such as for aluminum processing can include pneumatic valves and piping used to drive a crust breaking tool to create an aperture by breaking through the hardened upper crust layer formed on the bath. The crust breaking tool is intended to open the aperture to permit addition of additional alumina material to the molten bath of aluminum. When creation of the aperture has been confirmed, pressurized air directs the crust breaking tool to retract from the crust layer. The drawbacks of such systems include the large volumes of pressurized air which are used to control a normal crust breaking operation, and particularly when crust material forms on the crust breaking tool such that bath detection cannot occur, and/or when the crust breaking tool cannot penetrate the crust layer.
In these situations, the crust breaking tool can remain in the bath for an undesirable length of time which can damage the crust breaking tool, or render the detection system inoperative. Also in these situations, the subsequent feeding of new alumina material into the bath can be hindered, or the system may be unable to identify how many feed events have occurred, thus leading to out-of-range conditions in the bath. A further drawback of known control systems is the large volume of high pressure air required significantly increases operating costs of the system due to the size and volume of high pressure air system requirements, power consumption and cost, the operating time of pumps/compressors, and the number of air compressors and air dryers required for operation.
This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.
According to several embodiments of a piston rod and cylinder seal device for an aluminum bath crust breaker, a crust breaker device includes a cylinder defining a piston chamber extending between opposed first and second cylinder heads. A piston is slidably disposed in the piston chamber. A piston rod is connected to the piston. A piston rod spud extends from the piston rod including a shaft receiving bore having a first seal member in the shaft receiving bore. A hollow tubular shaft is connected to the second cylinder head. The shaft is aligned to be slidingly received in the shaft receiving bore and sealed by contact with the first seal member when the piston contacts the second cylinder head.
According to other embodiments, a crust breaker device includes a cylinder defining a piston chamber extending between first and second cylinder heads. The second cylinder head has a spud receiving bore, a pressure passage communicating with the spud receiving bore, and a bore supply/vent passage. A piston is slidably disposed in the piston chamber. A piston rod is connected to the piston having a piston rod spud including a shaft receiving bore. A hollow tubular shaft connected to the second cylinder head in the spud receiving bore has a central passage communicating with the bore supply/vent passage. The shaft is sealingly received in the shaft receiving bore when the piston rod spud is received in the spud receiving bore preventing pressurized air in the bore supply/vent passage from entering the spud receiving bore. The shaft is positioned outside the shaft receiving bore when the piston rod spud is outside the spud receiving bore.
According to further embodiments, a crust breaker system includes a cylinder defining a piston chamber having a cylinder head. The cylinder head has a spud receiving bore, a pressure passage communicating with the spud receiving bore, and a bore supply/vent passage. A piston is slidably disposed in the piston chamber. A piston rod is connected to the piston, the piston rod having a piston rod spud including a shaft receiving bore. A hollow tubular shaft is connected to the cylinder head and positioned in the spud receiving bore. The shaft is sealingly received in the shaft receiving bore of the piston rod spud when the piston rod spud is slidingly received in the spud receiving bore thereby isolating the bore supply/vent passage communicating pressurized air to the shaft from the pressure passage communicating with the spud receiving bore. The shaft is positioned outside of the shaft receiving bore when the piston rod spud is outside of the spud receiving bore. A pneumatic valve system includes a first control valve; and a valve position control line connecting the first control valve to the pressure passage.
Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. For simplification, not all parts are shown in all views of the drawings.
Example embodiments will now be described more fully with reference to the accompanying drawings.
Referring to
Referring to
Piston 24 is connected to a piston rod 26 which can include a crust breaker rod 28 connected to piston rod 26, or forming a free end of piston rod 26. Piston rod 26 extends through first cylinder head 14 and is slidably disposed using a rod bearing/seal 30 such that pressure within piston chamber 20 is contained by rod bearing/seal 30. At an opposite end of piston rod 26 is provided a piston rod spud 32 which is slidingly disposed in a spud receiving bore 34 when the piston 24 contacts second cylinder head 22.
A hollow tubular shaft 36 is connected to second cylinder head 22 and is slidably received within piston rod spud 32 when piston rod spud 32 slidingly enters spud receiving bore 34. A fluid pressure such as pressurized air can be introduced through hollow tubular shaft 36 from a bore supply/vent passage 38 created in second cylinder head 22. A pressure supply/vent port 40 is also provided with second cylinder head 22. Air pressure supplied at pressure supply/vent port 40 can be directed into spud receiving bore 34.
Referring to
It is further noted that an annular passage 53 is provided between piston rod spud 32 and a cushion seal ring 54 which is connected to second cylinder head 22. A sliding clearance is provided between piston rod spud 32 and cushion seal ring 54. Cushion seal ring 54 as known in the art allows pressurized fluid such as pressurized air in second portion 20b of piston chamber 20 to pass from second portion 20b into spud receiving bore 34 as the piston 24 and piston rod spud 32 both travel in the piston return direction “A”. During pressurized operation, annular passage 53 also provides an opposite passageway for compressed or pressurized air to pass between spud receiving bore 34 and into second portion 20b.
Referring to
To displace piston 24 within piston chamber 20, a pressurized fluid such as pressurized air is introduced for example into first portion 20a which acts against a first piston face 64 displacing both piston 24 and piston rod 26 in the piston return direction “A”. This displacement of piston 24 also co-displaces piston rod spud 32 into spud receiving bore 34. When piston rod spud 32 contacts and is sealingly engaged to tubular shaft 36 using first seal member 46, any fluid in central passage 50 and shaft receiving bore 42 is isolated from spud receiving bore 34. Therefore, as piston 24 continues to move in the piston return direction “A”, fluid, such as pressurized air in second portion 20b of piston chamber 20, is compressed between a second piston face 66 and a head face 68 of second cylinder head 22. Pressurized air in shaft receiving bore 42 is therefore displaced via a flow path including central passage 50 and bore supply/vent passage 38. Pressurized air in spud receiving bore 34 is outwardly displaced via a pressure passage 69 in communication with spud receiving bore 34.
Tubular shaft 36 is connected to second cylinder head 22 using a male threaded end 70 of tubular shaft 36 which is threadably engaged in second cylinder head 22 in female threads created in a shaft receiving bore 72. Bore supply/vent passage 38 is open to shaft receiving bore 72 via a connecting passage 74.
Referring to
Referring to
Referring to
Crust breaker system 94 can include a first pressure source 106 which can be aligned by control of a first control valve 108 and a second control valve 110 to direct pressurized air from first pressure source 106 via a first air supply/vent line 112 into first portion 20a of piston chamber 20 to hold piston 24 in the piston first contact position shown. To displace piston 24 in the piston drive direction “B”, first and second control valves 108, 110 can be realigned such that pressurized air from a second pressure source 114 can be directed through an air delivery/vent line 116 and a second air supply/vent line 118 into spud receiving bore 34 to act on second piston face 66 while simultaneously first portion 20a is vented to atmosphere via a path including first air supply/vent line 112 and second control valve 110.
When piston rod spud 32 is fully received within spud receiving bore 34, air delivery/vent line 116 and second air supply/vent line 118 are both vented to atmosphere through second control valve 110. A valve position control line 120 which connects air delivery/vent line 116 to a first operating side of first control valve 108 is also vented to atmosphere at this time. Piston chamber 20 is therefore not pressurized to the full pressure range of first pressure source 106 because the vented valve position control line 120 directs first control valve 108 to isolate first pressure source 106 from piston chamber 20. Pressurized air in a third pressure source 122 maintains this position of first control valve 108 while maintaining a pressure in a pressure transfer line 124 which is connected to bore supply/vent passage 38 in second cylinder head 22. Pressure in pressure transfer line 124 also pressurizes shaft receiving bore 42 but does not provide enough force to overcome the air pressure in first portion 20a of piston chamber 20.
Pneumatic valve system 96 further includes a solenoid operated valve 126 which directs pressure from a fourth pressure source 128 to opposite ends of second control valve 110. By changing the orientation or position of solenoid operated valve 126, second control valve 110 can be positioned to pressurize either the first or second portion 20a, 20b of piston chamber 20. Electronic signals used to coordinate the positioning of solenoid operated valve 126 as well as feedback signals from contact between crust breaker rod 28 and aluminum melt bath 102 are received and/or generated using a control device 129.
Referring to
As second piston face 66 of piston 24 displaces away from a contact position with first conductive biasing member 76, a first switch 130 having first conductive biasing member 76 connected thereto, opens a circuit signaling that piston 24 has left the piston first contact position with head face 68. When first piston face 64 of piston 24 second conductive biasing member 78, a second switch 132, having second conductive biasing member 78 connected thereto closes a circuit signaling that piston 24 is proximate to or has contacted first cylinder head 14, defining a piston second contact position. These circuit signals are received in control device 129.
When crust breaker rod 28 either creates or extends through aperture 98 of crust layer 100 and enters aluminum melt bath 102, a voltage V2 of the aluminum melt bath 102 is sensed and conducted via an electrical path including crust breaker rod 28, piston rod 26, piston 24, conductive seal 60, cylinder 12 to control device 129. When the voltage V2 of aluminum melt bath 102 is detected at control device 129, a signal is transmitted to reposition solenoid operated valve 126, which subsequently repositions second control valve 110. This position change of second control valve 110 isolates pressure from second pressure source 114 and providing a flow path for pressure from first pressure source 106 to re-enter first portion 20a of piston chamber 20. Piston 24 will thereafter return in the piston return direction “A” to the piston first contact position shown in
Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.
The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.
When an element or layer is referred to as being “on,” “engaged to,” “connected to,” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to,” “directly connected to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.
Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,” “lower,” “above,” “upper,” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.
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