Fischer & Porter Company

Masahiro Kazahaya

Jean-Pascal Valentin

Pierre Maitre

John J Bonner

A laser welding technique for joining two parts together, the parts having contacting faces which define an interfacial region. One part is permeable to a laser beam directed toward and focused on the interfacial region, the face of the other part having light-disruptive characteristics whereby when the beam impinges thereon, multiple internal reflections are produced within the interfacial region which trap the energy of the beam to generate sufficient heat to cause the parts to superficially melt and fuse.

Laser welding technique

A telemetering system wherein a transmitting device responsive to an input signal derived from a sensor representing a metered variable, such as temperature or flow rate, is adapted to generate a corresponding direct-current signal. This signal is conveyed over a two-wire line to a receiving station through a terminal resistor across which a voltage signal is developed corresponding to the incoming current signal. The receiving station includes a DC power supply whose output is fed over the same two-wire line to the transmitting device to provide operating power therefor. In order to enhance the power available to the transmitting device, the current signal generated by the transmitting device lies in a 0% to 100% signal range in which the ratio of direct-current I.sub.o at 0% signal to direct-current I.sub.100 at 100% signal is greater than 1/5 or 0.2. However, the voltage signal developed across the terminal resistor corresponds to the current signal and is converted to yield an output voltage signal in a 0% to 100% range in which the ratio of voltage V.sub.o at 0% signal to voltage V.sub.100 at 100% signal is equal to 1/5 or 0.2, thereby making it possible at the receiving station to operate receivers such as controllers and recorders which respond to an input voltage signal of this type.

Two-wire DC signal telemetering system

A differential pressure-transducer of the capacitive type that includes a drum-shaped insulating body whose flat opposing faces each have a circular back-up nest indented therein covered by an insulating diaphragm to define a cavity. The underside of each diaphragm is metallized as is the base of the related nest to form the electrodes of a variable capacitor whose value depends on the degree and direction of diaphragm deflection. Interconnecting the cavities is a plurality of internal ducts of small diameter that extend between the bases of the nests. Admitted through one of the ducts and filling the cavities is an incompressible dielectric fluid. Hence when an increase in high pressure applied to the face of one diaphragm acts to deflect this diaphragm inwardly, the fluid in the related nest is forced through the ducts into the nest for the low pressure diaphragm which is then deflected outwardly. Because the combined diameter of the ducts is relatively large, the resultant flow path is substantially unrestricted and the time constant of the transducer is short. And even when the diaphragm is deflected inwardly to an extent causing it to abut the base of the related back-up nest and to block one or more of the ducts, the remaining ducts remain free and prevent latching of the diaphragm caused by vacuum effects or surface tension of the fluid.

Differential pressure transducer

An auxiliary channel coupled to a selected loop in a plurality of process control loops included in a direct digital control system, the channel serving to expand the frequency response of the selected loop. The system is provided with a digital computer acting as an electronic controller common to all loops, each loop including a transducer sensing a particular process variable to produce a corresponding analog input signal which is digitized and compared in the computer with a set point signal to yield, after conversion, an analog output signal for operating a final control element in the loop to correct for process variations. The analog input signals from the respective loops are sequentially fed into the computer through a multiplexer at a relatively slow sampling rate whereby the loops are normally responsive only to the low-frequency component in the sampled process variables representing slow changes. The input signal from the selected loop is also fed into the auxiliary channel which includes a filter that passes the high-frequency component in the process variable to an amplifier whose output and the output signal from the selected loop are applied to an adder to produce a composite output signal for operating the final control element in a manner rendering the selected loop responsive to the full range of slow and rapid process variations.

Auxiliary channel for direct digital control system

A pressure transmitter for sensing fluidic pressure to produce an indication that is converted into a signal for transmission to a remote station. The transmitter includes a sensor constituted by a diaphragm which seals a chamber in a meter body subject to fluid pressure, the diaphragm being axially dilated in accordance with the applied pressure. Anchored on the diaphragm is an upstanding force beam which is pushed thereby in the axial direction. A range spring which is offset with respect to the axis of the beam is connected between an intermediate point on the beam and the meter body. The spring acts to constrain axial motion of the beam, whereby when the diaphragm is dilated by fluidic pressure, the beam is caused to deflect to an extent determined thereby. A motion detector is operatively coupled to the upper end of the beam to convert the deflection thereof into a corresponding signal for transmission.

Pressure transmitter

An electronic differential-pressure transmitter responsive to a difference between two pressure values to generate an output signal proportional to differential pressure for transmission to a remote station for acuating indicator or process control equipment. The transmitter is of the open-loop type that includes a pivoted force-beam to the lower end of which is applied an input force dependent on differential pressure, the resultant deflection of the beam being sensed by a motion detector coupled to the upper end thereof to produce the output signal.

Open-loop differential-pressure transmitter

A multiplex telemetering system for transmitting a group of data signals each representing a distinct analog value, over a common channel to a receiving terminal where the data signals are fed into respective sub-channels. The transmitter includes a commutator formed by a series of individually actuatable switches which sequentially supply the data signals to the common channel. At the receiving terminal, the data signals are distributed by a corresponding commutator to the several sub-channels. In order to synchronize the operation of the commutators, an address generator at the receiving terminal cyclically produces a series of multi-bit binary values the number of values in the series equalling the number of switches in each commutator. The series of binary values generated are decoded to produce control voltages for sequentially actuating the receiver commutator switches, the binary values also being translated into an audio signal mixture composed of different frequencies representing the bits of the binary code. The signal mixture produced at the receiving terminal is conveyed over the common channel to the transmitter, the mixture being superimposed on the data signals. The signal mixture is intercepted at the transmitter and the frequencies thereof segregated from each other and restored to a series of binary values which are decoded to produce control voltages for synchronously actuating the transmitter commutator switches.

Growing community of inventors

Southampton, PA, United States of America

Masahiro Kazahaya