Abstract: An air cannon has a pressure vessel, a discharge valve, and a discharge tube assembly. The discharge tube assembly comprises a fluid passageway and a blast guard valve. The discharge valve is capable of opening and closing and allows pressurized gas to be discharged from the pressure vessel into the fluid passageway of the discharge tube assembly only when open. The blast guard valve is capable of opening and closing and obstructs the fluid passageway of the discharge tube assembly when closed. The blast guard valve allows gas to pass through the fluid passageway when open. The discharge valve and the blast guard valve are operatively connected to each other in a manner such that the discharge valve can open only when the blast guard valve is open.

Abstract: An air cannon has a pressure vessel, a discharge valve, and a discharge tube assembly. The discharge tube assembly comprises a fluid passageway and a blast guard valve. The discharge valve is capable of opening and closing and allows pressurized gas to be discharged from the pressure vessel into the fluid passageway of the discharge tube assembly only when open. The blast guard valve is capable of opening and closing and obstructs the fluid passageway of the discharge tube assembly when closed. The blast guard valve allows gas to pass through the fluid passageway when open. The discharge valve and the blast guard valve are operatively connected to each other in a manner such that the discharge valve can open only when the blast guard valve is open.

Abstract: An air cannon has a pressure vessel, a discharge valve, and a discharge tube assembly. The discharge tube assembly comprises a fluid passageway and a blast guard valve. The discharge valve is capable of opening and closing and allows pressurized gas to be discharged from the pressure vessel into the fluid passageway of the discharge tube assembly only when open. The blast guard valve is capable of opening and closing and obstructs the fluid passageway of the discharge tube assembly when closed. The blast guard valve allows gas to pass through the fluid passageway when open. The discharge valve and the blast guard valve are operatively connected to each other in a manner such that the discharge valve can open only when the blast guard valve is open.

Abstract: An improved bulk material conveyor belt scraper comprises a skirt that shields mounting surfaces from the bulk material dust. By shielding the mounting surfaces from bulk material dust, such dust does not interfere with the replacement of the scraper blade. The belt scraper also comprises an improved securing mechanism for attaching belt scrapers to belt scraper mounts. The improved securing mechanism comprises pegs that have an elongate transverse cross-section that more evenly distributes bearing loads between the belt scrapers and their respective mounts. This eliminates local yielding that can cause belt scrapers to become loose over time.

Abstract: An air cannon has a pressure vessel, a discharge valve, and a discharge tube assembly. The discharge tube assembly comprises a fluid passageway and a blast guard valve. The discharge valve is capable of opening and closing and allows pressurized gas to be discharged from the pressure vessel into the fluid passageway of the discharge tube assembly only when open. The blast guard valve is capable of opening and closing and obstructs the fluid passageway of the discharge tube assembly when closed. The blast guard valve allows gas to pass through the fluid passageway when open. The discharge valve and the blast guard valve are operatively connected to each other in a manner such that the discharge valve can open only when the blast guard valve is open.

Abstract: An improved bulk material conveyor belt scraper comprises a skirt that shields mounting surfaces from the bulk material dust. By shielding the mounting surfaces from bulk material dust, such dust does not interfere with the replacement of the scraper blade. The belt scraper also comprises an improved securing mechanism for attaching belt scrapers to belt scraper mounts. The improved securing mechanism comprises pegs that have an elongate transverse cross-section that more evenly distributes bearing loads between the belt scrapers and their respective mounts. This eliminates local yielding that can cause belt scrapers to become loose over time.