Abstract: The valve assembly 20 has two housing halves 22 which are bolted together to form a housing 24 for two resilient valve liners 26 with coaxial through passages 28 for the flow of fluids through the assembly. A metal gate 30 selectively blocks the through passages 28. Each valve liner 26 has a radially extending flange 32 in which is embedded a frustoconical metal spring 34 which biases the flanges against the gate 30 and retains a seal about the gate in a valve closed configuration. The assembly has a split seat formed by two seat inserts 36 retained in the housing halves 22 beneath the valve liners 26. The seat inserts 36 are open to the bottom of the housing 24 and permit debris to be ejected from the valve assembly 20. The spring may be formed to have ends which are not connected and positioned by inserting a locator tab on the exterior flange of the liner into a corresponding depression in the valve housing.

Abstract: The valve assembly 20 has two housing halves 22 which are bolted together to form a housing 24 for two resilient valve liners 26 with coaxial through passages 28 for the flow of fluids through the assembly. A metal gate 30 travels vertically within the housing 24 to selectively block the through passages 28. Each valve liner 26 has a radially extending flange 32 in which is embedded a frustoconical metal spring 34 which biases the flanges against the gate 30 and retains a seal about the gate in a valve closed configuration. The assembly has a split seat formed by two seat inserts 36 retained in the housing halves 22 beneath the valve liners 26. The seat inserts 36 are open to the bottom of the housing 24 and permit debris to be ejected from the valve assembly 20. An alternative embodiment valve assembly has a wave spring which applies a force through an embedded ring to bias the valve liners against the gate.

Abstract: Centrifugal pumps suffer from wear of the annular seal (1) between the impeller (2) and the casing or side liner (3), due to the returning flow of the rejoining fluid (9). The present invention ameliorates this problem by having the clearance of the annular seal (10, 11) at least adjacent the inlet (6) of the impeller (2) sloping, in the direction of the main fluid flow (7) into the impeller inlet (6), at an angle of between 0.degree. and 60.degree. to the axis of rotation of the impeller (2).

Abstract: An erosion and corrosion resistant ferrochromium alloy comprising the following composition, in wt. %, 34-50 chromium, 1.5-2.5 carbon, up to 5 manganese, up to 5 silicon, up to 5 molybdenum, up to 10 nickel, up to 5 copper, up to 1% of each of one or more micro-alloying elements selected from the group consisting of titanium, zirconium, niobium, boron, vanadium and tungsten, and balance, iron and incidental impurities.The alloy has a microstructure comprising eutectic chromium carbides in a matrix comprising one or more of ferrite, retained austenite and martensite, as herein defined. Optionally, the microstructure further comprises one of primary chromium carbides, primary ferrite or primary austenite in the matrix.

Abstract: A centrifugal slurry pump casing which reduces localized wear behind the cutwater caused when the pump operates at less than the best efficiency point flow rate. By reducing the throat area (13) of the casing (12) in the region of the cutwater (14) to 30-70% of the discharge neck (17) at the discharge flange (18), recirculation and vortexing due to slurry re-entering the volute is substantially reduced.