Abstract: A centrifugal pump comprises an impeller which rotates at the center of a volute casing. The open side of the casing is closed by means of a wear plate which is fixed relative to the casing and which has a central inlet opening. The impeller includes a rear plate and a plurality of curved blades radiating from an open central portion of the rear plate. An annular plate is fixed to the outermost edges of the blades at the inlet side of the impeller. A cylindrical sleeve extends in an axial direction from near the inner edge of the annular plate through the opening in the wear plate. The annular plate and sleeve protect the edge of the wear plate and impede grit and sand entering between the annular plate and around the opening and the wear plate causing wear when the pump is used to pump slurry containing grit or sand.

Abstract: An overspeed safety braking device comprising an input shaft, the speed of which is to be braked when it exceeds a limit value, a rotary friction brake having a fixed part and a rotary part, the input shaft being permanently coupled for rotation with the rotating part of the rotary friction brake, a control device for applying the brake, and centrifugal activated structure comprising a braking member which rotates with the input shaft when the speed is below the limit value, a weight pivotally mounted on the braking member and biasing spring coupled to the weight and arranged to bias the weight toward the axis of rotation of the shaft when the speed is below the limit value and away from the axis of rotation when the speed is above the limit value.

Abstract: Compounds of the general formula ##STR1## wherein each of R.sup.1 and R.sup.2 independently represents a hydrogen atom or an optionally substituted alkyl, cycloalkyl or aryl group, or R.sup.1 and R.sup.2 together represent an optionally substituted alkylene group;each of X and Y independently represents one of the groups CR.sup.6 R.sup.7, C=O, C=N--Z, CH--NH.sub.2 ##STR2## in which n is 2 or 3;R.sup.6 represents a hydrogen atom, an optionally substituted alkyl or aryl group or a group of formula --OA in which A represents a hydrogen atom, a heterocyclyl group, an acyl group derived from a carboxylic or a substituted carbamic acid, or a group CR.sup.10 R.sup.11 R.sup.12 ;R.sup.7 represents a hydrogen atom or an optionally substituted alkyl or aryl group;Z represents a hydroxy, alkoxy, acyloxy, amino, alkylamino or dialkylamino group;R.sup.3 represents a hydrogen atom or an optionally substituted alkyl group;each of R.sup.4 and R.sup.

Abstract: Certain 3-phenylmethoxytetrahydropyrans, useful as herbicides.

Abstract: Novel tetrahydrofuran derivatives which are compounds of the general formula I or the N-oxides or salts thereof ##STR1## wherein each of R.sup.1 and R.sup.2 independently represents a hydrogen atom, a halogen atom, or an optionally-substituted alkyl, cycloalkyl or aryl group, or R.sup.1 and R.sup.2 together represent an optionally-substituted alkylene group; each of R.sup.3, R.sup.4, R.sup.5 and R.sup.6, any two or more of which may be the same or different, represents a hydrogen atom, a halogen atom, a mono- or di- alkylamino group or an optionally substituted alkyl, alkoxy, alkylthio or aryl group, or R.sup.3 and R.sup.5 have one of these meanings and R.sup.4 and R.sup.6 together represent a carbon-carbon bond; R.sup.7 represents a hydrogen atom or an optionally-substituted alkyl group; each of R.sup.8 and R.sup.

Abstract: Novel tetrahydrofuran derivatives which are compounds of the general formula I or the N-oxides or salts thereof ##STR1## wherein each of R.sup.1 and R.sup.2 independently represents a hydrogen atom, a halogen atom, or an optionally-substituted alkyl, cycloalkyl or aryl group, or R.sup.1 and R.sup.2 together represent an optionally-substituted alkylene group; each of R.sup.3, R.sup.4, R.sup.5 and R.sup.6, any two or more of which may be the same or different, represents a hydrogen atom, a halogen atom, a mono- or di- alkylamino group or an optionally substituted alkyl, alkoxy, alkylthio or aryl group, or R.sup.3 and R.sup.5 have one of these meanings and R.sup.4 and R.sup.6 together represent a carbon-carbon bond; R.sup.7 represents a hydrogen atom or an optionally-substituted alkyl group; each of R.sup.8 and R.sup.

Abstract: The method of casting a representation of a photograph that includes forming an etched plate through a half-toned screen of the photograph, making a mold cavity of the plate, making a wax impression of the rubber mold with the wax impression not completely copying the rubber mold, forming a casting of the wax impression, coloring the surface of the casting and sanding and burnishing the surface to remove the coloring from the high areas to produce a cast surface having tonal and height contrasts.

Abstract: Certain benzyloxymethyltetrahydrofuran derivatives are useful as herbicides.

Abstract: Compounds of the formula ##STR1## wherein R.sub.1 is alkyl; R.sub.2 is alkyl, aryl or aralkyl; R.sub.3 is hydrogen or alkyl or R.sub.2 and R.sub.3 together is polymethylene; and R.sub.4 is 2,6-dihalobenzyl are useful as herbicides.

Abstract: Certain novel trihydric alcohol derivatives, useful as herbicides and fungicides.

Abstract: Certain benzyloxymethyltetrahydrofuran derivatives are useful as herbicides.