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Sensors, monitors, controls for pressure only: product lines reviewed.

Sensors, Monitors, Controls FOR PRESSURE ONLY


Offers a complete line of pressure transducers and transmitters for industrial monitoring. Pressure ranges from 3 to 5000 psi are available, along with a variety of input/output configurations. Millivolt, voltage, frequency and 4-20 mA outputs are available on standard products. Complete media isolation is achieved on company's Model 88 series transmitter with stainless-steel wetted parts.


Manufactures pressure transmitters for ranges from 0 to 40 in. [H.sub.2O] to 0 to 3000 psi. Process connections as small as 1/2 in. npt are available, as are anti-flanges in various sizes.


Offers a complete line of melt-pressure transducers for standard or special applications in extrusion or injection molding processing. Products include:

* PT420 high-accuracy pressure transducer for critical pressure and temperature measurements, +/-5% accuracy in ranges to 30,000 psi, rigid- or flexible-stem configurations, and integral thermocouple model.

* PT460 economical pressure transducer with reliable, cost-effective pressure measurement, +/- 1.0% accuracy in ranges from 500 to 30,000 psi, rigid- or flexible-stem configurations, and integral thermocouple model.

* PT460 amplified-output pressure transducer for long-distance transmission without noise interference; easier interface with PLCs or computer-based extruder control systems and 4-20 mA, 2-wire; 0-5 VDC, 4-wire; 1-6 VDC, 3-wire; 0-10 VDC, 4-wire; or 1-11 VDC, 3-wire outputs.

* PT240 process industry pressure transmitters for high-temperature applications, including synthetic fiber spinning and melt extrusion; Factory Mutual approved for Class 1, Division 1, Groups B, C and D hazardous areas; flange-mount or threaded-mount; and 4-20 mA and voltage outputs.

* PT460XL enhanced-performance pressure transducers with extra-thick sensing diaphragm for improved corrosion resistance, high accuracy up to 30,000 psi and 750 F, and zero shift due to temperature change.

* PT130 hydraulic-pressure transducer which detects shot-to-shot variations and irregularities during feeding, measures injection ram and clamp, encompasses contoured sensing diaphragm for greater accuracy, repeatability and fatigue strength, and has 3 mV/V, 5V, 10V or 4-20 mA outputs.

* PT465XL nozzle-pressure transducer with flexible armored cable for longer life, ability to measure actual melt pressure within an injection molding machine or hot runner, 8-mil-thick flush diaphragm, and accurate measurements up to 30,000 psi and 750 F.

* PT449 direct-cavity pressure transducer, which mounts flush within the cavity, displays high-accuracy up to 400 F mold and 600 F melt temperatures.

* Indirect cavity-pressure transducers measure pressure from behind an ejector pin or sensing pin, install easily in space-restricted areas, with ranges from 0-50 to 0-2200 lb and up to 450 F.

* Mechanical/electronic melt-pressure gauges provide reliable, local indication on plastic/rubber extruders, easy-to-read gauges, and resistance to vibration.


Manufactures (in the U.S.) Model 818 PID melt-pressure controller for extrusion market. Controller accepts a 350-ohm, strain-gauge input and incorporates its own transducer power supply. Front panel features an auto/manual station and high-visibility dual displays for simultaneous viewing of measured value and setpoint. A simple front-panel procedure calibrates the input transducer. Digital or analog communications are available, in addition to two-alarm outputs. Separate rate limits can be applied to both setpoint and output signals. Instrument is fully configurable to facilitate implementation by OEM and end-user.


Offers a full line of plastic-melt pressure transducers/transmitters. Transducers feature a blend of integrated circuit and mechanical design technology. Filled transducers provide 0.5% FSO accuracy and a diaphragm that is 25-50% heavier than usual. Units have completely encapsulated electronics and an all-welded stainless-steel housing with permanent identification on an etched stainless nameplate. For more demanding applications the ruggedized models 136, 137, 138 and 139 provide a heavier diaphragm.


Manufactures transducers and instrumentation. Pressure-transducer instruments are available in accuracies of 0.5% or 1.0% and have stem lengths in either 6 or 12 in. and pressure ranges from 1000 to 20,000 psi. Options offered include metric-thread dimensions, corrosion- and abrasion-resistant diaphragms, and waterproof wiring.

Analog- and digital-pressure indicators are available with "D" option, which is used for triggering an alarm relay. Standard voltage outputs are: 0-1, 2, 5 and 10 v d-c. Optional 4-20 mA output is available on all indicators.


For extrusion throughput stabilization by closed-loop feedback control of pressure at the die, company offers a line of microprocessor-based pressure controllers. Mounted in a convenient plug-in 1/4 DIN module they feature read-out of pressure on large LED numerals, plus separate LCD display to allow any calibration and mode changes, and are available in both single-channel and differential-pressure control forms. Differential-pressure control is particularly useful in the control of melt pumps, where it can greatly increase metering accuracy, and is also useful for control of continuous screen changers.


Company's Industrial Automation & Controls Div. offers a full line of ST 3000 Smart Pressure Transmitters, which are available for process applications where flow, liquid level, gauge pressure and absolute pressure, and even vacuum must be precisely measured and controlled.

With a Smart Field Communicator (SFC), the ST 3000 can be remotely configured, re-ranged, diagnosed and can display process values. A 400:1 turndown ratio allows one model ST 3000 to be used for many applications. In its analog mode, the ST 3000 is accurate to +0.1% of span. In its DE (digitally enhanced) mode, the ST 3000 is accurate to +0.75% of span or +0.15% of reading, whichever is smaller.


New Terwin 1100 series pressure transmitters from Terwin Instruments Ltd. of England are designed for plastic, rubber and food extrusion. They have a two-wire 4-20 mA output and incorporate company's proprietary force-rod transducers, which are constructed entirely of stainless steel and use no mercury or other toxic substances. Temperature stability is claimed to be better than 0.005% per 1/2 F. Pressure ranges are available from 500 to 30,000 psi and temperature's capability to 842 F. All have abrasion-resistant diaphragms, come in a range of stem lengths, and reportedly conform to NEMA 12 standards for protection against moisture and dust.

IN USA markets Terwin's complete line of extruder pressure/temperature instrumentation.


Manufactures high-temperature melt-pressure transducers for the extrusion process. A complete instrumentation line is also offered to monitor and alarm the on-line pressure. Company also manufactures self-contained pressure gauges for extruders to replace grease gauges. High-level outputs (4-20 mA, 0-5 v d-c, 0-10 v d-c) are available on all melt pressure transducers.


A broad line of pressure transducers from Wika of West Germany is being introduced in the U.S. by a new subsidiary, International Pressure Products ([IP.sup.2]). The stainless-steel transducer offer absolute, vacuum, and gauge ranges from 0-5 psi up to 0-15,000 psi, with outputs of either 4-20 mA or 0-5 v d-c, and overall accuracy of 0.25% full scale. Sensors are of the piezo-resistive type. The amplifier and other sensitive components are encased in silicone gel for protection against contamination and vibration.

NPT process connections or flush-diaphragm versions are standard for hydraulic, pneumatic, or viscous-fluid pressure measurements (e.g., for tank-level sensing), though the company does not offer products for direct melt-pressure sensing. [IP.sup.2] stocks more than 3500 transducers, allowing same-day shipment.


Company reportedly manufactures the only piezoelectric (quartz) transducer for measuring cavity pressure in a thermoset and thermoplastic injection molding process, and is said to have the smallest in-cavity sensing device (2.5mm).

Company offers both direct and indirect measuring systems. Mold temperatures are sensed with a J-style thermocouple. Transducers that measure bar strain ensure even clamp loading and prevent tie-bar breakage.

In addition to transducers, company carries a full line of electronic-charge amplifiers to interface transducers to injection molding machine controls. Charge amplifiers can be used to control the molding machine or to give 0-10 v outputs for monitoring and data acquisition.

Company also intends to market software for SPC and a piezoresistive unit for measuring extruder melt pressure.


See Gentran.


Company's Super TJE pressure transducer employs a "square-bridge" design whose input and output resistance is made to equal 350 ohms +/- 1.5%. An outer-shell design enables unit to achieve superior stability (0.0015% per degrees F temperature compensation) and is calibrated in a separate production facility to ensure superior accuracy, temperature compensation, and reliability.

Available in gauge or absolute types and in ranges from 30 to 3000 psi, the Super TJE utilizes select electronics to insure 0.05% accuracy and has a welded stainless-steel construction to ensure long life. Units provide an unamplified output signal of 3 mv/v and optional internal electronic amplified signal of 0-5 v d-c or 4-20 mA and has a 1.7 in. diam. and is 3.25 in. long with amplifier.


Company's Data Acquisition & Control Systems (DACS) Division manufactures its 500 series comprising dataloggers, data acquisition, process control, and hot-runner control products. Company specializes in electric heater control and also in circulating fluid control for heating or cooling. Process information can be easily evaluated in the company's software. System sizes vary from stand-alone 8-channel systems, to 96-channel hot-runner systems, to 1000-channel multidrop distributed systems. Most industrial temperature sensors, transducers, transmitters, or conditioned signals can be fed directly into the 500 series units. Scale, offset, high, low, process high, process low, deviation, and band conditions and alarms can all be set from the front panel or a remote computer.


Offers a broad range of stainless-steel and brass pressure gauges for plastics processing.

* Process gauges, accurate to 0.5% of full scale; 4-, 6- and 8-in. diam; copper alloy, brass, and stainless wetted parts; 1/4-in. or 1/2-in. npt bottom or lower back connection.

* Industrial gauges; 1% F.S.; 3-, 4-, 6- and 8-in. diam.

* Severe duty; liquid fillable; 1% F.S.; 2 1/2- and 4-in. diam.

* Small gauges; 1 1/2 in. and 2 in.; stainless-steel case with brass or stainless-steel internals.

* Small gauges; 2 in. and 2 1/2 in.; all stainless steel with one-piece polycarbonate screw-on bezel and lens.

* Low-pressure gauges; 4- and 6-in. diam.; capsule or bellows element; provide combination of ranges from 10 in. [H.sub.2O] to 120 in. [H.sub.2O]; 1/4 in. NPT bottom or lower back connection.

Company also offers duplex, receiver, precision, differential-pressure, and transmitter gauges.


See IN USA, Inc.


See International Pressure Products.
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Title Annotation:1990-1991 Manufacturing Handbook and Buyers' Guide
Publication:Plastics Technology
Date:Jul 15, 1990
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