Abstract: A safety station for use in a process plant includes one or more leverless limit switches to detect activation of one or more parts of the safety station. The safety station further includes a wireless transmitter coupled to the leverless limit switches to transmit signals associated with the safety station to a base station device, which is communicatively coupled to one or more control and/or monitoring devices.

Abstract: A valve signature diagnosis and leak testing device includes a spool valve operatively connected to a pilot valve, the pilot valve being configured to position the spool valve to one of an open position and a closed position. A blocker valve is fluidly connected to a control fluid outlet of the spool valve. An electrical module is operatively connected to the pilot valve, a supply of control fluid, and the blocker valve, the electrical module being capable of sending pulsed electrical signals to the pilot valve and the blocker valve to selectively position the spool valve and the blocker valve to an open or closed position.

Abstract: An automatic speed searching device for a partial stroke test of a control valve includes a spool valve operatively connected to a pilot valve and a blocker valve. An electrical module is operatively connected to the pilot valve, a supply of control fluid, and the blocker valve. In an open position of the spool valve, a first control fluid inlet is fluidly connected to a first control fluid outlet, and in a closed position of the spool valve the first control fluid outlet is fluidly connected to a second control fluid outlet. A method of determining an optimum stroke speed includes iteratively powering a main and secondary solenoid in the electrical module and updating parameters to move a control element of the control valve until movement of the control element is within a desired range.

Abstract: A poppet valve assembly to control a pneumatic actuator may include a housing having a central bore. A first module may be disposed within the central bore, and the first module may have a first and second poppet valve. A second module may also be disposed within the central bore, and the second module may have a third and fourth poppet valve. A supply of pressurized fluid may be in fluid communication with a plurality of control valves such that pressurized fluid from the control valves opens and closes the poppet valves. The supply of pressurized fluid may also be in fluid communication with the first module and the second module such that the opening and closing of the poppet valves controls the position of the pneumatic actuator.

Abstract: A magnetic target is provided for use with a magnetic proximity switch. The magnetic target includes a cylindrical body tube having an open end that partially defines a bore. A stationary magnet is located within the bore opposite the open end, and a movable magnet is disposed within the bore between the stationary magnet and the open end. An adjusting member is received into the bore, and a contact surface of the adjusting member engages the movable magnet. When the adjusting member is axially displaced, the contact surface causes a corresponding displacement of the movable magnet relative to the stationary magnet, eventually causing the magnetic flux field of each magnet to expand in a radial direction away from the longitudinal axis of each magnet. The stationary magnet and the movable magnet may be either axially-magnetized samarium-cobalt magnets or axially-magnetized neodymium magnets.

Abstract: A magnetically-triggered proximity switch includes a cylindrical switch body and a bias member non-movably secured within the switch body. The proximity switch also includes first and second normally-closed contacts and first and second normally-open contacts. The proximity switch further includes a spherical contact magnet disposed within the switch body, with the contact magnet being movable relative to the bias member from a first switch position and a second switch position. In the first switch position, an attraction to the bias member maintains the contact magnet in contact with the first and second normally-closed contacts, thereby completing a circuit between the first and second normally-closed contacts. In the second switch position, an attraction to a movable target external to the switch body moves the contact magnet into contact with the first and second normally-open contacts, thereby completing a circuit between the first and second normally-open contacts.

Abstract: A magnetically-triggered proximity switch includes a cylindrical switch body and a first magnet non-movably secured within the switch body. The proximity switch also includes a pivoting cross arm. A second magnet may be movably disposed within the switch body, and the second magnet may be rigidly connected to the cross arm. When a magnetic target is not located within a specified range of the second magnet, the first magnet attracts the second magnet, thereby pivoting the cross arm into a first switch position and closing a first circuit. However, when the magnetic target is located within the specified range, the magnetic attraction between the target and the second magnet is greater than between the second magnet and the first magnet. The second magnet is displaced towards the target away from the first magnet, thereby pivoting the cross arm into a second switch position.

Abstract: A magnetic target is provided for use with a magnetic proximity switch. The magnetic target includes a cylindrical body tube having an open end that partially defines a bore. A stationary magnet is located within the bore opposite the open end, and a movable magnet is disposed within the bore between the stationary magnet and the open end. An adjusting member is received into the bore, and a contact surface of the adjusting member engages the movable magnet. When the adjusting member is axially displaced, the contact surface causes a corresponding displacement of the movable magnet relative to the stationary magnet, eventually causing the magnetic flux field of each magnet to expand in a radial direction away from the longitudinal axis of each magnet. The stationary magnet and the movable magnet may be either axially-magnetized samarium-cobalt magnets or axially-magnetized neodymium magnets.

Abstract: A rotary actuator comprises a housing, a shaft, at least one piston, and at least one closed-wound power spring coupled to the shaft. The housing defines a cavity. The shaft is disposed supported within the cavity of the housing and adapted for rotational displacement between a first position and a second position. The at least one piston is supported within the cavity of the housing and operatively coupled to the shaft. The piston is adapted for sliding displacement in association with rotational displacement of the shaft. The at least one closed-wound power spring is disposed within the cavity of the housing and operatively coupled to the shaft. So configured, the closed-wound power spring biases the shaft and the at least one piston into a predetermined relationship.

Abstract: An electronic monitoring circuit to detect unbalanced voltage conditions on a three phase alternating current line employs the charging current to a condenser connected across a full wave rectifier bridge to trigger a multivibrator circuit that controls an output relay in accordance with the multivibrator cycles per cycle of the power line voltage.