The Singer Company

Edward J Mateja

George Obermann

Wilbert E Beller

James M Thornbery

A flow rate sensor includes a diaphragm operated switch coupled to a Venturi in a flow conduit. The apparatus includes a housing having a diaphragm defining a chamber. The chamber has a first port connected to the Venturi and a second vent port. A valve connected between the first port and the diaphragm is spring loaded so that the first port is normally open. In the absence of fluid flow, the Venturi pressure is zero under the diaphragm and the diaphragm is at rest in an up position so that the valve is open. With fluid flow through the Venturi, vacuum will build under the diaphragm so that the diaphragm will travel down until the valve closes the first port. With the valve closed, pressure under the diaphragm will increase due to flow through the vent port and the diaphragm will move up. The valve will remain closed until the diaphragm up stroke is equal to the valve stem lost motion. The valve will then open and the process will cycle so that the diaphragm oscillates at a rate that bears a relationship to the square of the fluid flow rate through the Venturi. A sensor coupled to the diaphragm produces a pulsating digital signal, from which signal the flow rate may be calculated.

Digital fluid flow rate sensor

The timing (program) cam is driven at timing speed through a gear train which includes a clutch. When a delayed start is desired the timing cam must be positioned at the start of a cycle so a lever sensing the cam position will move a tiltable jackshaft to an active position in which the worm gear on the shaft can be engaged by a manually set ratchet segment while a cam moving with the segment de-clutches the timing speed drive. The worm gear rotation drives the ratchet back to zero at which time the clutch is engaged and normal timing begins. The number of ratchet teeth engaged with the worm gear determines the length of the time delay.

Timer with delayed start capability

The rotating program drum of the timer operates the timer switches in a predetermined sequence. One or more timer switches can be disabled to omit the function of the switch. Means are rotatably mounted in the frame to move a passive switch blade away from the active blade so the active blade cannot contact the passive blade. In two embodiments the disabling means operates on a switch at the end of the program drum while a third embodiment can operate on any of the switches operated by the drum.

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Hillside, IL, United States of America

Edward J Mateja