Options include: Fluid Flow Meter, Fluid Pressure Meter, Particle Filter, Deionized Water Compatible, Analog Interface, RS-232 interface, Remote Start/Stop Capability, and Flourinert compatible. Please indicate, on the Chiller Quote Request Form, any items you are interested in learning about.

Most compressors are available for 110/120VAC but check with PolyScience customer service for the particular model you are interested in learning about.

This is determined by the fluid and temperature range and operating pressure. We want to be sure that we choose plumbing that is compatible with the fluid to avoid deterioration of the pipes or contamination of the fluid. For example, in a DI water system, we could use plastic pipe or stainless steel; for high temperature requirements, copper pipe or Teflon tubing would be used in place of the lower temperature rated plastics. Some customers require stainless steel for their application because of the products that it comes in contact with.

As you will see in the next question, the pressure determines the type of pump we use. It is also imperative to select the proper size of pump; all pumps are specified with a GPM at some PSI. A one-quarter horsepower pump might be able to put out 10 GPM but not with any pressure. Likewise, a similar sized pump may be able to build up plenty of pressure, yet at a very small flow rate. This is the same as specifying both voltage and current requirements for an electrical appliance.

Choosing the right size chiller adds to the economies of its use. The optimum size needed is based on the amount of heat your application is generating, plus additional power to maintain temperature under varying loads. The PolyScience catalog contains information and a formula to help you select the correct size chiller. In many cases, the manufacturer of the device you are trying to cool will be able to tell you how much cooling (in watts or BTU's) is needed, or we may already know from past experience what is required. If this information is not readily available, contact PolyScience and we will assist you in determining your cooling requirements.

To assist us determining the cooling capacity required, some initial information is helpful to have on hand when calling: - the difference between the incoming and outgoing temperature of the fluid temperature of your instrument , in °C or °F. - the time to fill a one liter or one gallon container - the type of thermal fluid used (even if it's water) and if possible, the specific heat and weight of the fluid Additional information may be required.

To calculate the heat load of your system, use this formula:

Watts = ΔT° x (K) / S

Where:

ΔT = The difference between incoming and outgoing tap water temperatures of your instrument. Measure carefully using the same thermometer for both locations. You may measure in Celsius or Fahrenheit.

S = The number of seconds to fill a one liter container.

K = Conversion constant for density and specific heat of water, and the ratio to convert units measured into Watts per hour for Celsius or Fahrenheit. (Measured in: Celsius = 4,186, Fahrenheit = 2,326)

Additional Considerations:
• If ambient temperature of the cooling location is above 20°C, add 1% to the calculated wattage for each 0.5°C over 20°C.
• If operating at 50Hz, add 20% to the calculated wattage.
• If line voltage is consistently below rated voltage, or if you work at high altitude, add 10% to the calculated wattage.
• Future growth cooling needs or variability of heat output of existing unit.

Alex Red is available to assist in calculating chiller size for your application.

Temperature accuracy is determined by how close the indicated display agrees with an accurately calibrated standard thermometer. Temperature stability is the indication of how the temperature at a point in the system varies with time. The design of the chiller's circulation system, location of sensors and Cool Command™ technology make the thermal fluids and therefore the stability quite consistent.

Chillers are often rated in BTU/hr or Kilowatts (kW hr) or Watts. These are power specifications that refer to the amount of energy used over a period of time. 1 BTU/HR is the same as 3413 kW hr. On large systems with high BTU/hr ratings, the capacity is referred to in "tons". 1 ton is the same as 12,000 BTU/hr. Heat is also rated in kilowatts (kW). Maximum Watts of heat removal is determined by adding known watts of heat to the fluid system.

The temperature range, temperature stability, cooling capacity and pumping specifications are determined under controlled conditions. These include an ambient temperature of 20°C, 50% relative humidity, no external load attached, and where within range, distilled water is the fluid medium. For low temperature measurements lower than +5°C, we use Dynalene HC50™, or 50% ethylene glycol-water mixture. Your ambient and application conditions may vary from our standard conditions; therefore the results may be somewhat different than published specifications.

The two types available on PolyScience circulators are a pressure (simplex) pump and a pressure/suction (duplex) pump. The simplex pressure pump is typically used to push controlled temperature fluid through tubing, into the closed loop, and back into the reservoir. There is positive pressure throughout the circulating system. With a duplex pressure/suction pump, the pump produces pressure to the external closed loop application, and the liquid is returned to the circulator by the suction side of the pump. This duplex pump is suitable for maintaining liquid level in an open bath because it can return fluid to the circulator.

To achieve the desired temperature and desired rate of change. Often a system is required to go to an extreme temperature; however, it may not matter that it arrives at that point very quickly. In this case, a cooling capacity can be specified at a more conservative level, allowing for a lower power unit which may take up less space, less energy, and would be less costly.

Use of a remote probe permits the point of control to be switched from inside of a programmable circulator reservoir to the remote application. Because the temperature is now sensed at the point of need rather than inside of the reservoir, there is compensation for heat loss or gain between the circulator and the remote control point. These changes can result from varying room temperature, length of tubing, and changes at the point of application. Remote sensing allows for quicker response resulting in greater accuracy and stability where it is most necessary.

Basic steps for optimum results include the following: Keep the reservoir covered with the lid provided; insulate and minimize the length of tubing connecting the circulator with your application; increase flow by using the maximum diameter tubing possible; set the pump speed for best mixing; use a remote probe if you have a programmable controller.

No. PolyScience specifications are very conservative and you should see no variation in stability at settings within the published working range. Keep in mind that once a setpoint has been established; adequate time must be allowed for the temperature to stabilize. Depending on the reservoir size and where the new setpoint is compared to a cold or room temperature start, the time to stabilize could be substantial. Also, time to stabilize your external application must be considered.

As indicated previously, PolyScience specifications are determined under standard conditions of 20°C and 50% relative humidity. If these conditions are greatly exceeded, the circulator must work harder to maintain a stable temperature. Therefore, under extreme conditions, the control stability may be reduced. If the circulator is not in an air conditioned environment, locate it away from direct sunlight or other external heating sources such as heat and air conditioning vents, that may contribute to unwanted, variable temperature control. When selecting a unit for use in a non air conditioned area above 20°C, add 1% to the heat removal requirement for every 0.5°C over 20°C.

It is possible, but not recommended for consistency. A refrigerated circulator is preferable. Controlling fluid temperature close to varying ambient temperatures requires a consistent source of cooling, preferably refrigeration, in order to have the controller work properly. A tap water cooling coil in a heating circulator reservoir usually does not provide enough dependable cooling. The cooling must overcome external conditions such as fluctuating room temperature or internal conditions such as friction heating of the bath fluid caused by the mechanical action of the pump. Friction heating from the pump and fluid, plus transfer of heat from the motor to the pump impeller can cause the bath fluid to gradually rise 3 - 15°C over time. Depending on the type of pump, the temperature rise, even without the heater on, is sometimes much more. That is why PolyScience heating circulators are rated at the low end of their temperature range as ambient +5°C. Because of the temperature variability of cooling tap water, this specification is listed without the use of a cooling coil. The type of bath fluid, effectiveness of bath insulation and use of a bath lid also are important considerations when trying to control near ambient. For best results, a refrigerated circulator should be used when working close to ambient temperatures, even as high as 35°C. PolyScience circulators feature pump speed control to allow for operation closer to ambient through reduced friction heating.

There are four choices of circulator controllers. They are Programmable, Digital, Standard and Analog. The first three are microprocessor based, Proportional Integral Derivative (PID) controllers offering high levels of stability, digital set and read display, and varying levels of operating convenience, price and features. The Analog controller is an economical proportional controller requiring manual setting of the control point and thermometer readout. All controllers have a redundant safety backup. Greater detail can be found in the PolyScience catalog or contact PolyScience for help in selecting the appropriate model for your application.

The circulators models with a reservoir have 1/4" MPT internally threaded inlet and outlet for easy attachment to external equipment. Male inlet and outlet adapters for 3/8, 1/4, and 3/16 in tubing are supplied when units are shipped, along with a reservoir cover, one 2 Ft. length of insulated Buna N tubing, 6 ft. cord with standard grounded US plug on 120V models and European plug on 240V models. Additional accessories include a remote probe in 10, 25 and 50 ft lengths for the programmable models, Digital to analog communication adapter, PolyTemp Software, cooling coils, Tubing for high temperature up to 300°C, low temperature insulated tubing, Clamps, tubing, glass thermometer, Hollow plastic floating balls for insulating open baths, algaecide and bath cleaner.

The instrument or apparatus that is connected to the chiller usually mandates this and specifies this in gallons-per-minute (GPM) or liters-per-minute (LPM). This is typically a minimum value required to deliver the desired heat transfer. A higher flow rate is generally acceptable. If there is a pressure requirement, use care to determine the flow at the desired pressure.

Yes. The patented control techniques incorporated into the PolyScience circulators provide for seamless transitions between cooling to heating. Our refrigerated and heated combination units are specified with high precision over a wide temperature range.

In many cases, the manufacturer of the device you are trying to cool will be able to tell you how much cooling (in watts or BTU's) is needed. If this is not available, contact PolyScience for help. We may already know from past experience what is required, or we can help you calculate your needs for either a circulator or chiller.

To calculate the heat load of your system, use this formula:

Watts = ΔT° x (K) / S

Where:

ΔT = The difference between incoming and outgoing tap water temperatures of your instrument. Measure carefully using the same thermometer for both locations. You may measure in Celsius or Fahrenheit.

S = The number of seconds to fill a one liter container.

K = Conversion constant for density and specific heat of water, and the ratio to convert units measured into Watts per hour for Celsius or Fahrenheit. (Measured in: Celsius = 4,186, Fahrenheit = 2,326)

Additional Considerations:
• If ambient temperature of the cooling location is above 20°C, add 1% to the calculated wattage for each 0.5°C over 20°C.
• If operating at 50Hz, add 20% to the calculated wattage.
• If line voltage is consistently below rated voltage, or if you work at high altitude, add 10% to the calculated wattage.
• Future growth cooling needs or variability of heat output of existing unit.

Alex Red is available to assist in calculating chiller size for your application.

Cool Command™ is unique technology developed by PolyScience which combines microprocessor based controlling with pulse-width modulating valve refrigerant metering to provide the exact amount of cooling needed for your application. This results in more precise control, optimum cooling, and longer compressor life. Models equipped with the Cool Command system can provide cooling effects within the entire operating range of the unit. This means that a more rapid cool down from high temperatures is possible. Cool Command™

Temperature accuracy is determined by how close the indicated display agrees with an accurately calibrated standard thermometer. Temperature stability is the indication of how the temperature at a point in the reservoir varies with time or maximum deviation from average mean temperature for 1 hour @ 50°C, using water.

Circulators are often rated in Watts and BTU/hr. This is a power specification that refers to the amount of heat removed or added over a period of time. Note: Watt x 3.41 = BTUs/Hr.

The temperature range, temperature stability, cooling capacity and pumping specifications are determined under controlled conditions. These include an ambient temperature of 20°C, 50% relative humidity, Circulator lid on, no external load attached, and where, within range, distilled water is the fluid medium. For temperature measurements below +5C, we use Dynalene HC50™, or 50% ethylene glycol-water mixture. Silicone high temperature fluids are used above 100°C. Your ambient temperature and application conditions may vary from our standard conditions; therefore the results may be somewhat different than published specifications. All specifications are based on actual measurements, not averages as done by some manufacturers.

No. ALP pipettes are disposable pipettes, i.e. single use pipettes.
They must be destroyed after use, according to your disposal procedures.
Polystyrene is not autoclavable !

ALP pipettes are made out in crystal polystyrene.
Please check polystyrene resistance chart.

Sterile pipettes are guaranteed non cytotoxic, non haemolytic, non pyrogenic.

Yes. ALP pipettes are guaranteed non cytotoxic.

Accuracy is min. 98% at full volume.

All our sterile pipettes are Gamma irradiated (a "γ" label turns red during irradiation).