GB558460A - Improvements in apparatus for controlling the temperature of a fluid such as the cooling fluid or lubricating oil of an engine - Google Patents

Abstract

558,460. Fluid-pressure servomotor-control systems. NAPIER & SON, Ltd., D., and WALKER, G. E. L: . May 28, 1942, No. 7221. [Class 135] Apparatus for controlling the temperature of a fluid flowing in a circuit such as the cooling fluid or lubricating oil circuits of an internal combustion engine comprises in combination a heat exchanger through which pass both the fluid in the circuit and a. second temperature adjusting fluid, a valve for regulating the flow of this fluid actuated by fluid pressure under the control of an auxiliary valve actuated by a thermo-sensitive element located in the fluid circuit and a floating lever connected at spaced points along its length to the auxiliary valve, the thermosensitive element and a piston moved by hydraulic means when the regulating valve is moved. In the arrangement shown in Fig. 1, the thermosensitive element A is located in the cooling water circuit of an engine B1 which circuit also includes a heat exchanger B<SP>2</SP>. The flow of air through the heat-exchanger is controlled by a hinged valve D actuated by a double-acting piston E<SP>1</SP> working in an oscillating cylinder E. The supply and exhaust of pressure fluid to the cylinder is controlled by a piston valve J connected by a link J<SP>1</SP> to one end of a floating lever O, the other end of which is connected by a rod M<SP>3</SP> to a piston M loaded by a spring M<SP>1</SP> while an intermediate point O<SP>1</SP> is coupled by a rod A<SP>1</SP> with the thermo-sensitive element. As the valve D is moved by the piston E' a second piston N<SP>1</SP> coupled by a rod N<SP>2</SP> to the valve and working in an oscillating cylinder N forces or withdraws liquid from the cylinder L housing the piston M so moving the piston and floating lever to give a follow-up action. Should the piston reach the end of its stroke to the right before the valve D is fully open a projection M<SP>2</SP> unseats a spring- loaded ball valve L<SP>3</SP> to admit additional fluid from the supply conduit K'. Similarly excess movement in the other direction allows fluid to escape to drain through a passage L<SP>2</SP> uncovered by the piston. In the arrangement shown in Fig. 2 the valve D is actuated by a piston E<SP>6</SP> working in cylinder E<SP>5</SP> connected directly to the control valve J by a pipe F<SP>2</SP> and indirectly by a pipe F<SP>3</SP>, cylinder L and restricted passage R. The follow-up piston M housed in the cylinder L is urged towards its mid-position by a pair of springs T, T. The two sides of the piston M are connected through passages L<SP>6</SP>, L<SP>7</SP> fitted with restrictions R, S so that after a regulating operation the springs T, T' can slowly return the piston M to its mid position.