Extremely Fast Conditioning Times

The Textile Conditioning unit is specifically designed to rapidly bring textile samples to the standard condition of 21°C and 65% RH. Depending on the weight of the sample, this system will bring samples to equilibrium within 1 to 3 minutes.

PGC's humidity generating systems are unique. By utilizing the "two-temperature" method of control, PGC is able to create an unrivaled stable environment (see chart below).

PGC considers all three parameters necessary for attaining a specific specification (control constancy, chamber uniformity, sensor accuracy), thus providing the specified tolerance of ±1°C and ±2% RH, but sensor accuracy and chamber uniformity must be added to this figure.

This system is constructed with durable, corrosion resistant stainless steel. Low watt density heaters and various safety cutouts are included.

A highly precise, digital hygrometer (temperature compensated) provides state-of-the-art accuracy while a user-friendly SmartPad provides optimum control. Their controller also features 60-segment programming, high/low (or deviation) alarms, and a serial communications port.

Low Thermal EMF Relays Reduce Thermocoupling

Coto Technology's 3500 and 3600 series Low Thermal EMF Reed Relays reduce thermocoupling and provide for true voltage measurements at very low signal levels. The 3500 & 3600 series Reed Relays address the problem of stray voltages introducing errors into the signal path when measuring low level signals (tens to hundreds of microvolts). Typically, as temperature increases, stray voltages are generated by "thermocouples" in the circuit, resulting from the dissimilar materials of a relay. Coto's low thermal relays incorporate a patented thermal chip, which provides thermal equilibrium while maintaining electrical isolation. This helps to compensate for the effects of thermal gradients, which cause EMF voltages. Coto's low thermal relays are available with maximum thermal EMF ratings between 0.5 V and 10 V and are 100% production tested. Other available features include: Switching voltages up to 1000VDC; dry- or mercury-wetted reed switches; up to 3-form-A switch configuration; control voltage of 5 or 12 VDC; and an optional electrostatic shield. In addition, Coto's low thermal relays have fast switching times (.07mS for turn-on and 0.1mS for turn-off) allowing for a high sample rate when monitoring several processes. The 3501-05-910 Low Thermal Relays are priced at $4.18 in quantities of 1000. Coto Technology also has a complete line of Solid State Relays (the G2 series) which inherently have thermal EMF ratings of less than 0.2 V. Contact your local sales representative or Coto Technology for additional details and assistance with specific applications.

Wetted inert components are surrounded by structurally rigid materials such as PFA-clad aluminum KYNAR®. The resultant design represents a unique combination of a rugged, mechanically rigid frame and the chemically inert wetted parts. Flow meters are also resistant to external, ambient corrosives. For the protection of personnel, each flow meter is supplied with a safety shield. Rotameters are supplied with or without built-in needle valves and are panel mountable by means of KYNAR® panel nuts.

PRINCIPLES OF OPERATION:

A cylindrical float freely moving inside a tapered flow tube comprises the flow measurement element of PTFE - PFA flow meters. The translucent PFA flow tube is installed vertically in-line in the liquid stream. As flow takes place, the float is propelled up inside the flow tube. The area between the float and the inside diameter of the flow tube gradually increases with the increasing flow. Correspondingly, the pressure lifting the float decreases until the weight of the float and its buoyant force come to equilibrium. At this point, the top of the float is lined up with a scale graduation on the flow tube denoting a discrete rate of flow.

SPECIFICATIONS:

• SCALES 0 to 10 markings
• STANDARD ACCURACY ±5% FS MAXIMUM OPERATING PRESSURE 100 psig (6.7 bars)
• MAXIMUM OPERATING TEMPERATURE 250°F (121°C)
• LEAK INTEGRITY individually leak tested and certified to a rating of 1 x 10-7 sccs of helium

MATERIALS OF CONSTRUCTION:

• FLOW TUBES PTFE, PFA FLOATS PTFE FRONT SHIELD polycarbonate
• WETTED PARTS PFA (flow tubes) and PTFE (end fittings and floats) and PCTFE (guide rods)
• CONNECTIONS 1/4 inch FNPT to 3/4 inch FNPT based on model selected

The 72 Series flow control servovalves are throttle valves for 3 and preferably 4-way applications. They are a high performance, two-stage design that covers the range of rated flows from 25 to 60 gpm at 1000 psi valve drop. The output stage is a closed center, fourway sliding spool. The pilot stage is a symmetrical double nozzle and flapper, driven by a double air gap, dry torque motor. Mechanical feedback of spool position is provided by a cantilever spring. The valve design is simple and rugged for dependable, long life operation.

Technical Data:

• Port Pattern: ISO 10372 - 06 - 05 -0 – 92
• Rated Flow (@ 1000 psi [70 bar] pressure drop): 25 gpm [100 l/min] to 60 gpm [227 l/min]
• Operating Pressure: 3000 psi [210 bar] 3000
• Step Response: (@ 3000 psi [210 bar] for 100% stroke): 10 - 32 ms

These valves are suitable for electrohydraulic position, speed, pressure or force control systems with high dynamic response requirements.

Principle of operation An electrical command signal (flow rate set point) is applied to the torque motor coils, and creates a magnetic force, which acts on the ends of the pilot stage armature. This causes a deflection of armature/flapper assembly within the flexure tube. Deflection of the flapper restricts fluid flow through one nozzle, which is carried through to one spool end, displacing the spool.

Movement of the spool opens the supply pressure port (P) to one control port, while simultaneously opening the tank port (T) to the other control port. The spool motion also applies a force to the cantilever spring, creating a restoring torque on the armature/flapper assembly. Once the restoring torque becomes equal to the torque from the magnetic forces, the armature/flapper assembly moves back to the neutral position, and the spool is held open in a state of equilibrium until the command signal changes to a new level.

In summary, the spool position is proportional to the input current and with constant pressure drop across the valve, flow to the load is proportional to the spool position.

Conductive Technologies, Inc. manufactures custom flexible heaters to match your specifications.Printed flexible heaters are constructed using several elements including positive-temperature-coefficient (PTC) materials for delivering heat. Such constructions can be designed to operate in a steady-state or limiting modes. In the latter mode the final temperature is bounded by the limiting resistance of the PTC material. Temperatures up to 80^oC can be achieved by allowing the heater to draw a small amount of current at a fixed potential. At the start of the heating the current draw is typically a few microamperes, but as the heater approaches equilibrium, the current requirement is diminished to a level that is necessary to maintain the limiting temperature.

This stand alone system consists of a HygroLab 3 microprocessor based indicator, a probe for the measurement of product samples, accessories and HW3 software. In AwQuick Mode,the system gives accelerated water activity measurement typically in 5 minutes. In the AwE Mode: conventional water activity measurement with automatic detection of equilibrium.

The system includes 2 sizes of sample holders and disposable sample cups, humidity calibration standards. It is a stand alone system for bench top use. It can also be used with the HW3 software for the capture of end values, etc. The HygroLab 3 indicator accepts a large choice of probes, suitable for the direct measurement of products in bulk and other applications.