Hoist is a device used for lifting or lowering a load by means of a drum or lift-wheel around which rope or chain wraps. It may be manually operated, electrically or pneumatically driven and may use chain, fiber or wire rope as its lifting medium. The load is attached to the hoist by means of a lifting hook. There are two different kinds of hoist wire rope hoist & chain hoist. Construction sites especially for buildings of more than five floors in height often employ hoists to lift workers and building materials.

Hold back pump is a self-regulating evaporation system for fully automatic and environmentally friendly vacuum distillations. The pump operates without a controller by bringing physical condensation laws into practice. The evaporation pressure is adjusted automatically for any solvent or solvent mixture. The distillation process runs automatically without any interruption no matter how many different solvent fractions are to be distilled. This pump guarantees a fully-automatic process without any manual adjustment or regulation and without time consuming and costly electronic controller.