Portable Liquid Chillers and Environmental Liquid Conditioners from Bemco Inc.

Portable Liquid Chillers

Bemco PCL-III portable fluid conditioners are furnished as free standing caster mounted systems, ready to provide a reliable and precisely controlled flow of temperature conditioned fluid.

To save floor space, these systems are also packaged with larger space simulators and thermal vacuum systems. Bemco’s A6H Standard Space Simulators, described on this Web Site, each include a fully integrated and appropriately sized PCL-III fluid conditioner.

They also make an ideal upgrade to an existing vacuum chamber or bell jar without thermal capability or an older thermal vacuum system or space simulator with obsolete controls, leaking pumps, dangerous circulating fluids, or environmentally unfriendly refrigerants. They are useful for conditioning ground systems that require concentrated heating or cooling. They are easily optimized to work with internal product heat exchangers and conductively coupled heating and cooling plates.

Recommended circulating fluids for use with Bemco PCL-III Liquid Chillers are shown in the chart below.

Manufacturer's	Primary Advantages	Primary Disadvantages	Temperature
Name	As a Circulating Fluid	As a Circulating Fluid	Range Maximum
d-Limonene	Citrus based food grade chemical	Combustible, odor, and residue (1)	-85 C to +150 C
FC77 Flourinert	No residue dielectric fluid	Limited range, environmental (2)	-85 C to +150 C
Galden HT170	No residue dielectric fluid	Very expensive, environmental (2)	-85 C to +150 C
Lexol 408	Common in older systems	Combustible and residue (1)	-55 C to +150 C
Paratherm CR	Synthetic hydrocarbon	Combustible at high temperature	-85 C to +150 C
Coolanol 25	Low volatility dielectric fluid	Residue and high viscosity	-45 C to +125 C (3)
PAO (4)(5)	Low volatility dielectric fluid	Residue and high viscosity	-45 C to +125 C (3)
Downtherm J	Very large systems, fluid cost	Environmental, materials, and handling	-55 C to +150 C
Propylene Glycol	Automobile Antifreeze, 50/50 Water	Low temperature limit and corrosion	-30 C to +120 C

Circulating Fluid Table Notes:

Applies if spilled or if a leak develops in the shroud or base plate under vacuum.
Has potential environmental problems due to long life of the chemical in the atmosphere.
High viscosity at low temperature makes pumping difficult. Recommended range is 10 C higher than shown.
Bemco is the largest volume maker of PAO Chillers for the Aerospace Industry in the United States.
Additional information on Bemco PAO Chillers can be seen here.

Standard Models:

Bemco Mechanically Refrigerated PCL Chiller

Standard PCL-III fluid conditioners use d-Limonene, a product of Florida Chemical Company and a derivative of citrus peel oil. This material has a strong citrus odor, has a GRAS rating (Generally Recognized As Safe) from the US FDA, and is commonly used in modern space simulators and thermal vacuum chambers. Other fluids can be substituted. If another fluid is preferred, consult your Bemco technical representative for a recommendation. Bemco makes custom fluid chillers over the temperature range of -115 C to +200 C. No single fluid covers the entire range. Special fluids, not shown above, many with unique challenges, are available on request.

Fluid circulating systems are furnished with magnetically sealed gear pumps up to about 50 gpm at an external loop pressure drop of 50 psid. Above this flow rate, magnetically sealed centrifugal pumps are offered up to 150 gpm at approximately 20 psid external loop pressure drop. Higher pressure capabilities are available on request. Please note that liquid nitrogen cooling is required below -65 C.

Model	Flow	External	Temperature	Cooling	Cooling
Number	gpm	Load, Watts	Range	Type	Hp
PCL3L-III	3	1500	-55 C to 150 C	LN2	None
PCL3M-III	3	1500	-55 C to 150 C	Mechanical	2 x 2
PCL8L-III	8	4000	-55 C to 150 C	LN2	None
PCL8M-III	8	4000	-55 C to 150 C	Mechanical	6.5 x 6.5
PCL15L-III	15	8000	-55 C to 150 C	LN2	None
PCL15M-III	15	8000	-55 C to 150 C	Mechanical	10 x 10
PCL20L-III	20	10000	-55 C to 150 C	LN2	None
PCL20M-III	20	10000	-55 C to 150 C	Mechanical	15 x 15

The thermal load capacity given is based on an external loop thermal rise of 5 C. The standard circulating fluid is d-Limonine and the standard pump type is Magnetic Gear.

PCL-III's Include:

The third generation PCL-III Portable Liquid Chiller combines the outstanding features developed in over 60 years of manufacturing these systems with modern controls, safer fluids, advanced heat exchangers, and convenient packaging.

Bemco refrigeration systems are all water cooled. They use environmentally friendly refrigerants, industrial grade semi-hermetic compressors, and include automatic hot gas bypass unloading as well as Bemco’s exclusive, high performance coaxial cascade heat exchanger. Heaters are interlocked with a separate heavy duty power contactor and a factory preset high temperature safety control.

All electrical wiring meets the United States National Electric Code. The electrical control panel is hinged for easy access. UL and CSA approved components are used where possible.

Fluid System

The standard Bemco PCL-III fluid circulating system includes a magnetically sealed, positive displacement gear pump capable of producing rated flow at 50 psi between the supply and return connection.

The fluid system includes shutoff valves, a bypass modulating valve to allow system preconditioning, discharge and suction pressure gauges, and a relief valve to protect the system from over pressurization.

The system also has a fluid reservoir with a sight glass to monitor fluid level as well as a nitrogen gas pressurization system to prevent boiling, water condensation, and to allow the fluid to expand and contract with temperature. Discharge and suction pressure switches protect the system. The PCL-III is enclosed in a carbon steel case painted Bemco blue.

Cooling

Mechanically refrigerated systems include a proportionally controlled cascade, two compressor, refrigeration system utilizing modern, environmentally friendly refrigerants to cool the circulating fluid. The system has automatic hot gas bypass and suction cooling unloading as well as Bemco’s exclusive high performance coaxial cascade heat exchanger.

All systems are water cooled, have thermal and current sensors on each compressor, and feature numerous safety and reliability protection systems for dependable operation.

For liquid nitrogen (LN2) cooled systems, fluid temperature is reduced by a proportionally controlled liquid nitrogen injection system and a heat exchanger utilizing both a control solenoid and a series mounted safety solenoid to positively interrupt nitrogen flow in the event of a malfunction. A relief valve and a line strainer are provided for dependable operation. A self-sealing vent system with an attachment coupling for remote piping by others, removes expanded nitrogen from the heat exchanger.

Controls

Each PCL-III includes a microprocessor based programmable 1/4-DIN solid state 256-step ramping temperature controller with a 4-line LCD interface display and a large red LED display.

An RS232 and RS485 interface is standard. The protocol is Modbus™. LabVIEW™ drivers are available.

A Factory Mutual Approved high and low temperature safety control with audible and visual alarm is included at no extra cost.

Mechanical Options

300 Series stainless steel exterior construction. See the first picture on this page for an example.
Micron sized, large desiccant and particulate filters in the return flow with isolation valves, a bypass valve, a differential pressure gauge, and a bypass solenoid to filter the system flow and remove entrained moisture if present. Dual sets are sometimes specified for continuous system operation.
A micron sized filter in the supply flow with isolation valves, a bypass valve, and a differential pressure gauge to remove contaminants in the supply flow.
An automatic pressure regulation bypass valve to maintain discharge pressure at a preset value.
A manual three-way reservoir bypass valve to allow captured gas bubble relief on initial connection to a load.
Automatic flow isolation solenoid valves.
Self sealing quick disconnect fittings.
Automatic flow modulation valves with automatic bypass modulation.
Fluid sampling ports to allow evaluation of fluid quality.
Outdoor fluid enclosures mounted on over-the road truck running gear with inflated tires and Ackermann (the front wheels turn with the yoke) steering.
Field generator sets to allow operation without a source of electricity. Please note that these systems are usually specified with an air cooled refrigeration system.
Dual heat exchanger loops, tanks, one for hot and one for cold with automatic mixing valves to allow a smooth rapid thermal transition between systems for temperature cycling between extremes.

Optional Instruments

24 hour or 7 day, digital indicating, self chart printing, circular recorders for temperature.
Single pen or multi-pen strip chart recorders.
Programmable logic control sequencing of test processes or fluid system sequencing including totally automatic control of all system functions. Systems can include calibration and maintenance screens and graphic representation of the system. Bemco recommends Allen Bradley (ABB) PLC’s and software.
Touch screen HMI’s (Human Machine Interfaces).
RS232, RS485, and Ethernet communication interfaces.
Digital liquid flow meters, either indicating or totalizing, calibrated in gpm.
Flow meters to indicate total system mass flow.
Automatic low and high level sensing and alarm in the fluid reservoir.
Automatic level sensing transducers in the fluid reservoir.
Low and high flow switches with audible and visual alarm and electrical interlocks.
Low and high pressure switches on the system discharge or suction line to protect the test item.
Precision pressure transducers on the fluid discharge and suction lines interlocked with display devices or system process controls.
Graphic display of control switches, system processes, set points, actual values, and status.

Fluid Distribution Panels

Optional fluid distribution panels and fluid control panels are offered to individually distribute, monitor, and protect one or more of your valuable products from higher than required flow or process conditions.

You can also use these units with any other source of temperature controlled fluid including other manufacturer's products. These systems are individually assembled to match the equipment being tested. They can be designed for mounting in standard Electronic Industries Association (EIA) 19” or 24” relay rack consoles or as free standing, wall, table, or floor mounted systems. A separate Web page describes these units. Please click here.

Available Literature Includes:

Bemco PCL and PAO Series, Portable Liquid Chillers and Polyalphaolefin PAO) Liquid Chillers. These units provide a flow of temperature controlled fluid or Polyalphaolefin liquid. Nine standard circulating fluids including d-Limonene, FC77 Flourinert, Galden, Lexol 408, Paratherm CR, Coolanol and PAO. Eight standard model Portable Liquid Chillers and ten standard model PAO Carts. Fluid distribution panels are also discussed. Document is 8 pages, 651 KB download.

The systems described above are our Standard Models. We make custom equipment to your specifications. If you have any questions, need assistance in preparing a specification, or have a technical problem you want help with, we are ready. Our quotations and advice are free.

Environmental Chambers and Space Simulation Systems