Abstract: A device for controlling the quantity of hydraulic fluid returned to a pump from a double-acting lifting cylinder for lifting and lowering a load which moves through a dead point includes a housing, a control piston slidable within the housing and defining two spaces within the housing, each of the spaces being adapted to be connected to a pump. Two further spaces are provided within the housing and adapted to be connected, one to each side of the double-acting lifting cylinder. Each further space is connected with one of the spaces by way of a valve, and each of the valves is operable by means of the control piston. During use, the quantity of hydraulic fluid allowed to return from the lifting cylinder, through one of the further spaces and its associated valve and space, and returned to the pump, is proportional to the displacement of the control piston which depends on the pressure exerted by the pump.

Abstract: A device for feeding fuel to a diesel engine including a fuel storage tank, a feed pump provided in a conduit between the fuel storage tank and the engine, and an injection pump for atomization. The injection pump is provided with a pressure control valve for reducing the excessive pressure to that of the pressure prevailing in the conduits and with a device for measuring the fuel consumption. Means are provided for substantially equalizing the temperature of the fuel in a return conduit and in the feed conduit, and for holding the fuel under excessive pressure in the feed conduit.