How does an ultra low freezer work


Ultra low freezer: how does it work?

What is an Ultra freezer?

The Ultra freezer is one of the main tools used in research laboratories. The ULT freezer safeguards biological samples important for research being carried out in laboratories, by keeping them at very low temperatures. The operating temperature can range from -45° C to -89° C. Two versions are generally available: vertical cabinet or horizontal unit with access from above. The most common one is the vertical version, as laboratories are increasingly looking to save space to make it easier to move around. The internal storage volume of the low temperature freezer can also differ. It can start from an internal capacity of 200 litres up to a maximum capacity of 800 litres. The Ultra freezer has shelves on the inside where research samples are placed. Each shelf is closed by an internal door so as to maintain the temperature as uniform as possible on the shelves where no sample is removed or placed.

In order to keep the cold stored inside the cabinet, between the external wall and the internal one, there is a pollutant free polyurethane insulation with high insulation coefficient, which keeps the temperature stable for several hours. Another key element to maintaining the freezing status is the seal which is positioned around the entire perimeter of the main access door. The most efficient ones are silicone quadruple-step seals, which guarantee even greater temperature stability. The main entry door, also insulated with polyurethane, guarantees the highest degree of coldness and is blocked by an external closure generally fitted with a safety key. The most practical laboratory freezers are equipped with pivoting wheels at the bottom, in order to make it more practical to move within the laboratory. The most modern freezers are equipped with electronic PLC controllers, and a display that indicates freezing parameters. The entire control system is generally equipped with a back-up battery, which ensures the digital temperature display works even when there is a power failure.

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Here you can see ultra low freezers for sale by FDM.

How does the refrigerator circuit of an ultra freezer work?

The refrigeration systems can be a single high-power compressor hermetically sealed or two cascade compressors. In this second case, there are two refrigeration circuits connected so that the evaporator of one cools the condenser of the other, facilitating the condensation of the compressed gas in the first circuit.

Air-cooled condensers are generally used in laboratory refrigeration systems, consisting of tubular batteries (copper or copper-aluminium) arranged to provide as much surface heat transfer as possible. In Ultra freezers, the circulation of the cooling air is forced by an engine driven fan and the expansion of the refrigerant fluids is obtained by capillary tubes.

Evaporation takes place through steel plate heat exchangers, located inside the chamber, or by means of a coil. In horizontal freezers, the copper or copper-aluminium coil evaporator is placed along the walls and bottom, while in vertical freezers it runs along the walls and at the top. The coil in the room eliminates the problems of efficiency in the heat exchange of freezers with the coil in the insulation cavity.


Coolant fluids used in the ultra low temperature freezers

Refrigerant fluids are selected from gaseous chemical compounds that can easily be liquefied and characterised by certain properties such as high critical temperature and low critical pressure, limited hazard and toxicity. They are indicated by the letter R followed by a number that refer to the molecule’s atoms. Each refrigerant system must be sealed and contain eco-friendly refrigerant HFC gas, free from CFC and HCFC as well as being non-explosive, non-flammable and non-toxic. The most efficient, environmentally friendly refrigerant fluids used in ultra freezers are typically R170, R23 and R290.


Which accessories can Ultra Freezer have?

The accessories generally supplied include: a CO2 and / or LN2 emergency system (both with independent power supply, probe and battery). In addition, in order to track room temperature, freezers are optionally equipped with a weekly charted temperature recorder, which has almost completely been replaced by digital ones. In line with current international standards, the recorder is compulsory for freezers at -45° C and -86° C for the storage of blood products. Other accessories include: various kinds of steel containers, drawers and racks for storage of cryoboxes, microplates, blood bags and test tubes designed for low and very low temperature storage. Handling goods inside the ultra freezers requires you to wear suitable protective headgear, leather gloves to protect your hands and overalls and smocks to protect your body.


Custom environmental test chambers: intro

Your special requirements deserve special solutions. For this purpose FDM has developed its custom division for made custom environmental test chamber. We can develop an environmental test chamber with dedicated volumes, removable doors or exceptional specimens testing are only few examples. We analyzed and developed things like machines for special mechanical tyres testing, climatic chambers filled with path tracks for mice testing and environmental chambers with special filters or lights. Our experience, and technical innovation skills, allow us to realize custom solutions to complicated testing needs for custom testing conditions. For this reasons we can produce custom environmental test chamber according to specific standards.

FDM real value is in the service you need. We are improving every day to give you the best. Confide in the FDM team; We have done custom test chambers for larger companies. Them needs was to improve your materials for make a better product. Check out below some of products that we have already done.

Customized climatic chambers that we had done:

Climatic module for hydraulic press

Easly coupled climatic module with any hydraulic press. With this module you can do hydraulic test press on specific enviromental conditions.

Main features of climatic hydraulic press are:

Temperature range: -30/+80°C

Temperature changes in time: ±0.1…0.5°C

Max Cooling / Heating Speed: +5/-5 °C/min


Light Climatic chamber

Climatic chamber for Keeping Mice, photo-period reproduction with temperature, humidity and light controlled.

Temperature range (° C) 0/+40

Temperature stability (K) ± 1

Humidity range (%) 30/80

Humidity fluctuation (%) ± 2,5



Cyclic Climatic chamber

Robust Cyclic climatic chamber for environmental test

Temperature stability of ±0.1°C

Temperature range –40°/+180°C

Temperature uniformity of ±1,5 °C

Touch Programmer with 1 program and 20 steps


More custom project

Stability testing

Stability testing for validation of pharmaceutical products that meet ICH Q1A

The stability testing is a procedure for products validation that meet different standards. The stability chambers are the best equipments for stability studies, and application of use are: Pharmaceutical Products/Packaging; Medical Products/Packaging; Personal Care Products; Consumer Products and Research. This stability chamber can ricreate an ideal environment with temperature, humidity and illumination that are need for test. Temperature range is 0°C to +70°C, humidity range is 10% RH to ±90% RH and the illumination meet ICH Q1A pharmaceutical stability guidelines for different conditions. The pharmaceutical testing require an controller that install the CFR 21 software that meet FDA 21 CFR part 11 compliant. The stability testing is used also for accelated aging test, in order to speed up its aging process on the differents temperature, humidity and lighting conditions.

Read our page dedicated to material test chamber!

FDM Stability chambers provide a uniform, temperature/ humidity conditioned environment for worry-free operation with a control system that is easy to use and saves time. These chambers are ideal for ICH Q1A pharmaceutical stability testing, shelf life, package testing, accelerated aging, and more. The Constant Touch Screen Controller is compliance with FDA regulation 21 CFR part 11 for ERES (Electronic Records and Electronic Signatures). The controller is designed to simplify chamber operation including data logging, ethernet control and monitoring from any device, alarm notification via email and/or text message, data fi le backup, full system security, audit trail, digital signatures, power recovery options, and more.

Stability testing – strong points:

  • Temperature range 0°…+70°C
  • Temperature stability of ±0.1…0.5°C
  • Control relative Humidity 10% to 90% ±3%
  • Constant controller touch screen with CFR 21 software
  • Data logging with network connection
  • Inner lexan door with differents compartments
  • IQ/OQ certifi cations included
  • GSM Module (optional)
  • Best quality component for a long-term simulation
  • Made in Italy Design and Product

ICH Q1A stability testing

Stability testing structure:

  • External manufactured completely in white plastic coated galvanized steel and internal in stainless steel AISI 304
  • Polyurethane insulation CFC and HCFC free
  • Reversible doors fitted with self-closing hinges with stop opening beyond 90° and replaceable magnetic gaskets
  • Inner lexan door for different compartments
  • Inside with rounded corners
  • Plastic-coated steel grids removable and height adjustable
  • Adjustable steel feet

CFR-21 software

CFR-21 Controller:

  • Colour touchscreen display
  • Peer to peer communications
  • Modbus master/slave
  • Profi bus master
  • 10/100Mbps Ethernet
  • Continuous and sequential control
  • Multi-setpoint programmer
  • Batch control
  • Recipes
  • USB support
  • 21 CFR Part 11 auditor
  • Data logging
  • Open communications
  • Alarm management
  • Multi-language support
  • Heat treatment application editor


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manufacturer of climate chambers

FDM: The manufacturer of climate chambers Leader in Italy

The historic company born in Rome in 1949, is the manufacturer of climate chambers Leader in Italy. FDM stands out for its solid “know-how”, acquired over time, and the commitment and professionalism it provides every day for its customers. FDM offers a range of products useful to scientific and industrial laboratories. The company also has a team of engineers specializing in custom products. Many researchers and big industry rely on our team to make customized solutions ready to perform specific tests they require.

Production of climate chambers for different types of tests

Each scientific or industrial laboratory needs to test a material in different and certain conditions. FDM produces climatic chambers for different types of tests. The growth chambers, useful to accelerate the growth process of plants or insects. Climate chambers for stability testing, useful for performing pharmaceutical tests. Temperature chambers, useful for testing materials under specific temperature conditions. The climate chambers or environmental chambers, which are specific for testing at variable temperatures and humidity conditions. Additionally, FDM produces climatic chambers for materials test, that can be used to determine freeze/thaw resistance on different types of materials.

Made in Italy; Crucial to producing climate chambers

FDM is constantly evolving and looking to improve its products. FDM believes in quality, made in Italy is at the base of our products. The climatic chambers produced are equipped with the best components. They provide greater reliability in the test, and give long life to the climatic chambers. Our mission is to improve test quality in research laboratory by providing timely and reliable machinery for multiple applications.

FDM speaks your language. Being present in Europe and extra UE contries gives us the possibility to support you with your requirements, at you side. Our policy is looking for distributors that, with our training, become expert in FDM equipment and will help you with ordinary and extra ordinary after sale maintenance. We know price is not the only valuable thing that matters. FDM Service and Support is present in: Spain, France, Poland, UK, Germany Benelux, Estonia, Switzerland, Greece, Serbia, Pakistan, Bangladesh, South Korea. Isn’t it enough? Discover our Remote Support by our Engeeering team.

Climatic hydraulic press

climatic hydraulic press

Climatic hydraulic press; Climatic module paired with any press

If you have a hydraulic press, and you need to do test at controlled temperatures and humidity, FDM has already the solution for you. We’ve put ourselves to the test once again, designing a unique machine and that allows the coupling with your current press.

The climatic chamber can be coupled and de-coupled to the press in a simple and fast way . Thanks to the installation of the chamber on rails. In this way, it will be enough to pull out the chamber’s axes and slide backwards the climatic structure. The project was born with the necessity of a customer, who was already in possession of a hydraulic press and wondered us if it was possible to create a climate coupled with it.  So we managed to meet the customer’s economic / qualitative needs by creating a custom machine for unique and efficient testing.


Main features of climatic hydraulic press are:

Temperature range: -30/+80°C

Temperature changes in time: ±0.1…0.5°C

Max Cooling / Heating Speed: +5/-5 °C/min


Other features of climatic hydraulic press:

Temperature and humidity probe are located close the Test sample

RS485 interface port

External elettronic controller with programmer

Controlled Humidity to avoid condensation

External glass door with inner lighting to the climatic

Internal and external structure completely in stainless steel AISI 304

Cable holes both wall sides.

The climatic hydraulic press, can work both with manual and automatic mode through the software already installed on the press with RS485 interface and external electronic controller.


Accelerated aging test


accelerated aging test

Manufacturer of accelerated aging chamber

Studying the effects of time over a product or material has always been quintessential for companies wishing to; determine and analyse the aging process on their products. FDM experts have come together to design an accelerated aging chamber which achieves just this; making sure your product hits the market having withstood all tests, including the test of time.

Offering a range of customisable settings, the FDM High Accelerated aging test puts your material which could be components from a variety of industries under time duress. Watch accelerated aging and test your product. This without having to spend a significant amount of time as was done in the past. With this accelerated corrosion test chamber, you can now run an accelerated weathering tester; which will enable you to witness the effects of time, weathering and corrosion on your product. Few other brands understand the importance of time as F.lli Della Marca do. We recognise how every second is a precious asset in your labs and we work hard to make aging testing sustainable for your finances and resources.

Choose FDM for your highly accelerated stress tests. With our powerful chambers you can now launch durable products your customers will appreciate more as time goes by.

Our Climatic chamber for Accelerated aging, is designed for make best environment for your material samples.

Accelerated aging chamber

Stability chambers

Stability Chambers – how to determine the durability of materials

Slated to be an ideal blend of technology and usage brilliance, Stability chambers is intended to identify the effects of pre-quantified settings on biological, electronic as well as industrial materials. They are manufactured smartly to detect a varied range of humidity levels and fluctuations in temperature. Such chambers are used effectively in finding the minutest of details in a particular product. Considering its usage, stability testing chambers are known to be a useful input in studying about the cells of a living being. With the need to control temperatures, there is always a need for products that are technically advanced.


Also famed as the constant climate chamber, such types of cells include ideating appropriate temperature, and other aspects are measured for their progress. Storing a variety of products require constant temperature adjustments, and no one has enough time to keep on operating the manual temperature control system. This is the reason that temperature and humidity simulation factors of the stability chamber are substantially developed by stability chambers suppliers. Indeed, they are powered to detect specific temperature required by a stored product to keep it safe. With such an excellent feature, these chambers are exquisitely equipped to perform brilliantly.


The road to their excellence does not end here; rather, such types of chambers are found competent in the matter of stability test for perishable products like vegetables. As a part of the testing process, one can identify the level of temperature required by them to survive. Ideally known, chamber encompasses a logger cap that circles a memory chip and a small range transceiver. It is linked to the sensor cap, whose chief function is to gather data and transmit it further. It is essential that before linking the above items, a logger cap must be aligned with the laptop. As the connections are made, it is attached to the sensor cap for initiating the test.

Besides being programmed to verify the temperature fluctuations, the stability chambers have varied usage points. It is quite often seen as a part of the pharmaceutical applications because of the need to store medicines at respective temperatures. As known, every medicine has its temperature level, and pharmaceutical stability chambers 

are considered as a boon for preserving medicinal properties. It is a perfect example of advanced technology that has enabled it to be used prominently in food industry and cosmetics as well.


Stability testing chamber is articulated for the stimulation of complex weather conditions, powered to handle extreme temperatures and humidity levels. Indeed, they are developed to maintain constant temperature chambers conditions for a longer time slot. It’s essential task is to retain the temperature level and ensure that better works are carried out. Also laced with the ability to be as humidity chamber, they are equipped with lighting and carbon-dioxide supplies.  Indeed, the cells positioned in the chambers are intended to provide equal distribution of temperature as well as humidity. The stability chamber manufacturer ensures that mechanisms created by them are exceptionally functional; so that the pharmaceutical companies can store medicines longer.


See also our Stability testing chambers

Plant incubator


Plant incubator

Plant incubator for grow up biologicals process

The new version of Plant incubator is more easy and reliable. Here in FDM we are constantly researching and upgrading our products. The shelf is more adjustable, and the maintenance is faster than ever.

We’ll be present with our new plant incubator at the AgrifoodTech fair in Eindhoven.

Water flooding system


Water flooding system

Water flooding system
This model (CB/S Series + SPS07 option) can provide/equip of a flooding and discharging water system.
It is composed by two vessels both in stainless steel:

Inner Vessel (volume 150 l):

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The maximum water level controller stops the water charging, during the flooding time. Water charged and discharged are both done by the hole at the bottom right of the inner vessel.
The outer vessel is composed of two rooms, one is the water vessel, and the other is the technical room of the water vessel. In this last room is contained the water pump, the discharge electro valve and the water temperature thermostat. This thermostat is set to 23°C from the manufacturer. It controls the water temperature contained in the outer vessel by the regulation of a bar-heating.

This option is compatible with the following standard:

EN 1348
EN 12004

You can equip the water flooding system with this series



ICH compliant illumination for climate chambers

We can produce climate chambers with any light source that is designed to produce an output similar to the D65/ID65 emission standard such as an artificial daylight fluorescent lamp combining visible and ultraviolet (UV) outputs, xenon, or metal halide lamp. D65 is the internationally recognized standard for outdoor daylight as defined in ISO 10977 (1993). ID65 is the equivalent indoor indirect daylight standard. For a light source emitting significant radiation below 320 nm, an appropriate filter(s) may be fitted to eliminate such radiation. This type of illumination is according Option1 of ICH Q1B guidelines.

In addition to ICH compliant illumination, we can produce cool white fluorescent lamp designed to produce an output similar to that specified in ISO 10977 (1993) ; and a near UV fluorescent lamp having a spectral distribution from 320 nm to 400 nm with a maximum energy emission between 350 nm and 370 nm; a significant proportion of UV should is in both bands of 320 to 360 nm and 360 to 400 nm. This type of illumination is according Option2 of ICH Q1B guidelines.

View all models of climatic chambers with illumination here