Seal assembly and method for providing a seal in a rotary kiln

A rotary kiln having a kiln chamber, rotating members, stationary members, and a seal assembly which provides a fluid-tight seal between the rotating members and the stationary members, comprising:

• a first chamber defined in part by rotating members and in part by stationary members,
• first seal means disposed between a rotating member and a stationary member for preventing fluid communication to the first chamber from the kiln chamber;
• a second chamber defined in part by rotating members and by stationary members and disposed so that the first chamber prevents direct fluid communication between the second chamber and the kiln chamber;
• second seal means disposed between a rotating member and a stationary member for preventing fluid communication between the first chamber and the second chamber;
• and
• third seal means disposed between a rotating member and a stationary member for preventing fluid communication between the second chamber and the atmosphere;
• so that should one of the seal means malfunction, the first chamber will not directly communicate with the atmosphere.

In a rotary kiln having a kiln chamber defined by rotating members and by stationary members, and being operated at a positive pressure, the method of providing a fluid-tight seal between the rotating members and the stationary members so as to prevent a loss of pressure from the kiln chamber, comprising:

• providing a first chamber which communicates with said kiln chamber via a first seal which only allows fluid flow from the first chamber to the kiln chamber;
• injecting a fluid into said first chamber at a pressure sufficient to cause the injected fluid to pass through said first seal so as to prevent kiln fluids from entering the first chamber;
• providing a second chamber separated from said first chamber by a second seal, and disposed such that said second chamber prevents direct contact between the second seal and the atmosphere, thereby preventing the first chamber from directly communicating with the atmosphere in the event of the second seal malfunctioning;
• and
• maintaining said second chamber at a pressure equal to or greater than the pressure within the first chamber.

In rotary kiln having a kiln chamber defined by rotating members and by stationary members, and said kiln chamber being operated at a positive pressure, the method of providing a fluid-tight seal between the rotating members and the stationary members, comprising:

• providing a first annular chamber defined in part by a rotating member and in part by a stationary member;
• providing said first annular chamber with two seals each disposed at the two junctions of the rotating member and the stationary member so as to complete the definition of said first annular chamber, the first of said two seals restricting the flow of fluid from said kiln chamber into said first chamber;
• continuously injecting a fluid into said first chamber so that the fluid pressure within said chamber is sufficient to cause said fluid to flow from said first chamber through said first seal and into said kiln chamber;
• providing a second annular chamber defined by a stationary member, a rotating member, the second of said two fluid seals, and a third seal, said second seal disposed between the rotating member and the stationary member and preventing fluid communication between the first chamber and the second chamber, and said third seal disposed between said rotating member and said stationary member and preventing fluid communication between the second chamber and the atmosphere;
• injecting a fluid into said second chamber so that the second chamber is maintained at a pressure equal to or greater than the pressure within the first chamber so as to prevent fluid flow from the first chamber into the second chamber;
• and
• venting said injected fluid from said second chamber.

In a rotary kiln having a kiln chamber defined by rotating members and by stationary members and being operated at a positive pressure, the method of providing a fluid tight seal between the rotating members and the stationary members comprising:

• providing an annular isolating chamber which directly communicates with the kiln chamber via passage means for only allowing fluid flow from the isolating chamber into the kiln chamber;
• injecting a fluid into said isolating chamber at a pressure sufficiently greater than the pressure within the kiln chamber so that the injected fluid will pass through said passage means from the isolating chamber into the kiln chamber to prevent kiln fluids from entering the isolating chamber;
• providing an annular seal chamber defined by a rotating, outwardly-facing, U-shaped annular rim, integral with said kiln, said rim having two opposing rim surfaces, and further defined by a stationary annular bellows chamber;
• separating the isolating chamber and sealing chamber with a seal disposed between the bellows chamber and one of said opposing rim surfaces;
• and
• injecting a fluid into said seal chamber so that its pressure is equal to or greater than the pressure within said isolating chamber so as to prevent fluid flow from the isolating chamber to the seal chamber, and
• venting said injecting fluid from said seal chamber so as to withdraw heat from said seal chamber.

A rotary kiln having rotating members, stationary members, a kiln chamber, and a seal assembly for providing a fluid-tight seal between the rotating members and the stationary members, comprising:

• a rotating kiln having an integral, rotating, outwardly-facing, U-shaped, annular rim providing two opposing rim surfaces;
• a stationary bellows assembly comprising two concentric expandable bellows sealingly attached to two opposed end sealing members so as to define a fluid-tight annular bellows chamber;
• said bellows assembly being disposed between the two opposing rim surfaces of the annular rim so as to define a seal chamber between the inner concentric bellow and the inside of the U-shaped rim;
• sealing means for providing a fluid-tight seal between the rotating opposing rim surfaces and the stationary members, wherein the sealing means prevents fluid communication between the interior of the seal chamber and the exterior of the seal chamber;
• and
• pressuring means for maintaining the bellows chamber at a pressure which sufficiently biases the end sealing members outwardly so as to maintain an effective seal between the end sealing members, the sealing means, and the rim surfaces.

A rotary kiln having a kiln chamber, rotating members, stationary members, and a seal assembly which provides a fluid-tight seal between the rotating members and the stationary members, comprising:

• a first chamber defined in part by rotating members and in part by stationary members;
• first seal means for restricting the kiln fluids from passing from the kiln chamber into the first chamber, and for allowing fluid to pass from the first chamber into the kiln chamber;
• a second chamber defined in part by rotating members and in part by stationary members, and being disposed so that the first chamber prevents direct fluid communication between the second chamber and the kiln chamber;
• and
• second seal means for providing a fluid-tight seal between the rotating members and the stationary members of the rotary kiln and for preventing fluid communication between the first chamber and the second chamber and between the second chamber and the atmosphere.