Magnetic pressure indicator with sampling ports

Claim 1

A magnetic pressure indicator providing for sampling of fluid without interfering with actuation of the device, comprising a housing and, disposed in combination in the housing, a first magnetic means in one chamber spaced from and arranged to react with a second magnetic means in a second chamber so long as the two magnetic means are within their mutual magnetic fields of force; first bias means to retain the first magnetic means towards or away from the second magnetic means; second bias means to propel the second magnetic means from a first position to an indicating position whenever the spacing distance between the two magnetic means is changed; the first magnetic means being movable in response to changes in pressure, and normally resiliently biased by the first bias means toward or away from the second magnetic means by a predetermined force, and the second magnetic means being normally resiliently biased by the second bias means in a direction away from the first means by a force capable of overcoming the force of magnetic reaction with the first magnetic means whenever the first and second magnetic means are spaced by a predetermined distance; at least two fluid line connections, one connection leading to said first chamber having the first magnetic means and the other connection leading to said first chamber on the other side of the first magnetic means, pressure in said line connections tending to move the first magnetic means in opposite directions; at least one sampling port in fluid flow connection with one of the fluid line connections; and valve means in the housing connected across the fluid flow connection from the sampling port to the other fluid line connection and selectively movable between open and closed positions, normally closing off the port, and accessible from outside the indicator to be activated for movement to an open position for removing a fluid sample via the port.