new products Edited by TED MILLER.

News from the Firms Strainstall Ltd., 90a High Street, Cowes, Isle of

Wight, have undertaken extensive strain tests on Europe’s biggest passenger carrying catamaran, M.V. Suerita, for the purpose of a Board of Trade certificate. Some 200 strain gauges were fitted to the twin hulls and sandbags simulated the all-up carrying load of 180 passengers in tests on the Thames near Greenwich. The owners, Catamaran Cruisers Ltd., intend to run the 60 feet long, diesel powered vessel capable of a speed of 12 knots between Greenwich and Hampton Court during the summer.

Automation Industries U.K., 20-22 High Street, Camberley, Surrey, announce the establishment of a Non - Destructive Testing Laboratory at Houston Road, Livingston, West Lothian, Scotland. A full com- merclal laboratory non-destructive testing service will be offered, including automatic ultrasonic testing, to industrial and commercial users whose needs do not warrant the purchase of equipment and training of personnel, or where volume of work overloads their own testing facilities.

Electro Mechanisms Ltd., 21 8-221 Bedford Avenue, Slough, Bucks., announce the following appointments: Mr. F. A. Ramage, Executive Director (Technical Sales), Mr. 0. J. Pilling, Executive Director (Engin- eering), and Mr. R. W. G. Pickard, Technical Sales Manager.

A New Stress Gauge Several instruments measure stress rather than strain

within a body. In a new approach an embedded cell adjusts its modulus automatically to match that of the host material and the pressure exerted is measured. The stress sensing head need not be thin and plate- like as usual but can have several sensitive axes to form a stress rosette.

A prototype with one sensitive axis has been con- structed and successfully tested at low stress values (up to 50 lbf/in2). Much higher values can be used, and extension to a multi-axis instrument is quite possible. The N.R.D.C. have taken out patents but further development depends on the answer to the question “Is there a need to measure stress as op-

posed to strain?” The inventor would be pleased to hear from persons interested in this work. J. R. GIBBS, PORTSMOUTH COLLEGE OF TECHNOLOGY, ANGLESEA ROAD, PORTSMOUTH, HANTS.

Electronic Thermometers New Braun Electronic instruments offer a con-

venient means of checking temperatures in the range a o 0 C to +4oO0c.

A hand-held probe is placed in contact with the part to be checked and the temperature is read off a clear, multi-range meter. The meter unit is fully tran- sistorised, battery operated and weighs only 11 02s. Additional probes are available and provision is made on all meters for connection to recorders. DE LA RUE FRIGISTOR LTD., CANAL ESTATE, STATION ROAD, LANGLEY, BUCKS. Phone: Slough 41218.

Bridge Completion Unit Strainstall have introduced a 5-channel strain-gauge

bridge completion unit to interface strain gauge circuit with galvanometers, recorders and other equipment. Input arrangements cover single-active or half-bridge circuits, connections being simply made by spring- loaded front panel terminals.

A ten-turn control on each channel provides stepless calibration and allows zeroing or backing off. Cali- bration is direct-reading with a full range of &-lo00 microstrain. A 3 position sensitivity switch enables optimum deflection to be obtained from differing strain levels. Internal protection prevents galvano- meter burn-out from faulty gauge stations.

The complete instrument, which is un-powered, measures 7) x33 x2) in. and costs €140. STRAINSTALL LTD., 9 0 ~ HIGH STREET, COWES, ISLE OF WIGHT. Phone: Cowes 2219/2360.

High Speed Multi-Channel Pen Recorders A new range of Linear Corder high speed pen re-

corders is announced by Environmental Equipments Ltd. Manufactured in Japan these solid state bench mounting recorders with integral amplifiers are avail- able in 2 to 12 channel versions. A floating-input mode allows direct measurement of signals at a high potential from earth and the instrument has a high sensitivity and high input impedance. Rectilinear recording is achieved by a unique design of pen movement eliminating ‘arc error’.

Frequency response is flat from d.c. to 80 Hz with a

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recording amplitude of 40 mm or from d.c. to 30 Hz with a recording amplitude of 80 mm. Other standard features include a timer pen and switched calibrated ranges covering spans of 5 mV to 500 ‘V with zero point adjustable over full scale and 9 chart speeds. ENVIRONMENTAL EQUIPMENTS LIMITED, DENTON ROAD, WOKINGHAM, BERKS. Phone: West Forest 4922.

Galvanometer As a further development, S.E. Laboratories has

introduced a new galvanometer for use in conjunction with their SE.4000 universal amplifying system and range of U.V. oscillographs. With its sensitivity of 2 mA/cm. into an internal impedance of 70 ohm and a flat frequency response from d.c. to 1600 Hz the galvanometer is ideally suited to give the maximum response from a 10 kHz carrier system to theSE. 4000 amplifiers. S.E. TRONICS, S.E. LABORATORIES LTD., 606 NORTH FELTHAM TRADING ESTATE, FELTHAM, MIDDLESEX. Phone: 01-890-1 166.

Galvanometer Drive Amplifier Model SE. 4510 d.c. amplifier is a single ended

floating solid state amplifier containing a regulated power supply for operation from 110-250 V, 50/60 Hz supplies. Although primarily designed to drive high- frequency galvanometers, the unit may also be used as an inexpensive wide-band amplifier to fulfil many d.c. instrumentation requirements.

Features include vernier, stepped gain control and zero shift control. Each channel is a self-contained unit, complete with connector suitable for bench use. Al- ternatively, up to 8 channels may be accommodated in the 3) in. rack carrier Series 4030 for standard 19 in rack, or bench mounting. S.E. LABORATORIES (ENGINEERING) LTD., NORTH FEL- THAM TRADING ESTATE, FELTHAM, MIDDLESEX. Phone:

High Stability Strain Gauge Pressure 01 -890-1 166.

Transducer Type RV22 pressure transducers cover a number of

pressure ranges from 0- I5 psi to 0- I500 psi. All models are temperature compensated and provide a high stability output with low hysteresis and 0- I repeat- ability. Variants include a model with built-in I.C. amplifier and stabiliser giving 2 V d.c. output, a high temperature model for continuous operation at 200°C and a fully waterproof model for complete immersion.

Prices range from E54 and delivery of most standard and high output models is from stock. COUTANT TRANSDUCERS, 47/49 MILFORD ROAD, READING, BERKS. Phone: Reading 40166.

Micro Miniature Pressure Transducer The new Kulite CP Series pressure sensors use a

monolithic integrated circuit Wheatstone bridge directly formed on a silicon diaphragm and provide substantial size and weight reduction, high output, low power dissi- pation, increase in natural frequency and reduction in pressure sensitive area. The CPL-070 Series of about * in. external diameter and 1 . 8 ~ 1 0 - 3 sq. in. pressure sensitive area is the smallest pressure sensor in existence and has pressure ranges of 4 psi up to 200 psi for static and dynamic pressure measurements.

The standard CPL-070 transducer has a reference tube emerging from the back and measures gauge pressure when this tube is left open to the atmosphere, differential pressures when it is connected to a pressure source (dry, clean, non-conductive gas), and absolute pressure when the reference pressure is a.vacuum. For biomedical applications it can be’supplied in a catheter with anticoagulant rubber tubing. ELECTRO MECHANISMS LTD., 21 8/221 BEDFORD AVENUE TRADING ESTATE, SLOUGH, BUCKS. Phone : Slough 27242.

DC Inductive Displacement Transducer By operation of a linear differential variable trans-

former (L.V.D.T.) at or near zero phase frequency, the effects of temperature can be compensated and a zero phase shift in the secondary achieved. With electronic circuitry in the transducer housing the basic ax. excited L.V.D.T. can be used in d.c. circuits with the same simplicity as the resistance potentiometer.

The Schaevitz d.c. L.V.D.T. made in the U.K. under licence provides all the d.c./a.c. conversion electronics within the transducer housing. Temperature-stable solid-state circuitry converts d.c. power into a.c. ex- citation, and an amplifier demodulator provides a filtered d.c. output of f5V for driving d.c. instru- mentation. The new Schaevitz Engineering DC-A L.V.D.T. has an output impedance smaller than 100 ohm, a dynamic range up to 500 Hz on the low dis- placement ranges, and k 10 V d.c. output for full scale displacement of the core. ELECTRO MECHANISMS LTD., 21 8/221 BEDFORD AVENUE TRADING ESTATE, SLOUGH, BUCKS. Phone : Slough 27242.

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