Abstract: An improved method of constructing a semiconductor device of the encapsulated type wherein a stack of members including a semiconductor element is encapsulated along with spring means ensuring compressive contact to the element contact areas. Hitherto up to five spring washers were needed to keep total spring deflection to within a value giving a desired compressive force, due to accumulated thickness tolerances of the stack members. In the present invention, a plastically deformable member is included in the stack initially along with a thickness gauge member such that bringing together the encapsulation housing parts round the stack flattens a single included spring washer and deforms the deformable member by a certain extent. This certain extent is such that when the stack is re-assembled without the thickness gauge, the plastically deformable member is now of a thickness to cause the spring to deform by an amount giving a desired compression force in the finished stack.

Abstract: A pneumatic liquid level sensing apparatus for marine tankers has a dip tube which by having air or gas applied to it bubbles into the liquid in a tank and produces a back pressure corresponding to the depth of the tube in the liquid, a pressure responsive valve device responsive to the back pressure relays a signal to a remote indicator and the provision of a balance pipe above the surface of the tanker liquid connected to a balancing input of the valve device enables the output of the valve device to be independent of the value of the air or gas pressure in the tank.

Abstract: A train braking system is provided which operates conventionally to effect braking by a reduction of pressure in a brake pipe and which includes on a car of the train a fluid flow sensor operating in response to a pressure gradient due to flow over a length of the brake pipe in the car or over an interposed restriction in the brake pipe, the fluid flow sensor being sensitive to such flow to operate a valve via which fluid is permitted to be applied to or removed from the brake pipe ahead of the restriction or brake pipe section having regard to the direction of propagation to tend to enhance a pressure change being caused by the flow.

Abstract: A fluid pressure comparison apparatus including a pressure responsive member displaceable by the difference between two pressure sources being compared to vent fluid from one of the sources, when its pressure is greater than the other, through a port whose aperture is varied by the displacement of the pressure responsive member. The flow of vented fluid is measured in one of many possible ways to determine the excess pressure. The measurement may be displayed on an indicator or applied to control associated equipment. Various arrangements embodying the apparatus may be used for flow indication, flow control, leakage detection and indication and as warning or control equipment. The pressure responsive member is shown as a nylon reinforced rubber diaphragm but the nature of the member will depend on the absolute as well as the relative values of the pressures compared.

Abstract: An improvement in the battery charging control circuit of our co-pending Application Serial No. 400,001, and more particularly a new means for detecting the onset of gassing during the charging of a battery, such as lead-acid battery.In the exemplary embodiment described in our co-pending Application Serial No. 400,001, the onset of gassing was assumed to be imminent upon the attainment of a particular battery cell voltage. The present invention provides an improved means for determining the true onset of gassing by recognition of a unique point in the temporal pattern of the differences between successive registered battery voltages as measured during interruptions of charging.