RU2103622C1 - Cryogenic device for prolonged storage of bioproducts - Google Patents

Abstract

FIELD: cryogenic engineering. SUBSTANCE: cryogenic device includes reservoirs-storages with tight covers; they are connected with common intermediate dispensing reservoir. Device includes cryogenic gas machine which is started automatically, automatic system for raising the pressure and dispensing the cryogenic fluid to reservoirs-storage according to indications of sensors fitted in each of them. EFFECT: enhanced efficiency. 1 dwg

Description

 The invention relates to cryogenic technology, namely the use of low temperatures for long-term (long-term) storage of biological materials.

 Known technical solutions for the freezing and storage of biological objects in the environment of a liquid cryoagent or its vapor. These devices use Dewar vessels that communicate with each other, in one of which the stored material is placed, and the second is a reserve consumable capacity for cryogenic liquid, from where it enters the first vessel as the cryoagent evaporates [1]. In an improved embodiment, the installation for cryopreservation of biological products [2] contains a container for liquefied gas connected by pipelines to its supply with chambers for the processed material, and there are cryoagent level sensors and a control unit for filling the chambers.

 Even more advanced technological thermostating systems are known, where the condensation of the vapor generated during the evaporation of a cryogenic liquid occurs due to the throttling of part of the liquid flow [3].

 Closest to the proposed invention (prototype) is a cryogenic device for storing biological products, consisting of a number of Dewar vessels connected by an overflow pipe through an intermediate cryogenic tank with a compensating vessel for a liquid cryoagent and having a system for maintaining a given level of liquefied gas according to the readings of level gauges [4 ].

 The disadvantage of most of the considered devices is that they are open-type systems requiring periodic refueling. Their work is associated with the irretrievable losses of the gradually evaporating cryoagent and the accumulation (in the case of using liquid nitrogen) of oxygen in the liquid phase, which is unacceptable under the conditions of storage of organic materials. To avoid the latter, it is necessary to periodically warm the system, associated with the complete discharge of liquid from the storage, extraction and transfer of storage objects to temporary thermostats. All this significantly increases overhead and can lead to damage and death of stored samples.

 This solution is aimed at solving the technical problem of improving the reliability of the device, creating a closed biometrics storage system capable of long-term operation in an autonomous mode, independent of external supplies of a cryoagent equipped with an automatic control system. This is ensured by the fact that the storage tanks are equipped with hermetically sealed lids, and the gas discharge lines of them are connected to the receiver-receiver and the working cavity of the automatically switched on cryogenic gas machine, the drain line of which is brought into the intermediate distributing container located under it, equipped with automatic pressure lifting systems and individual distribution of cryogenic fluid to storage tanks.

 The drawing schematically shows a cryogenic device for long-term storage of biological products.

 The cryogenic device contains storage tanks 1 and 2 of biological products equipped with hermetically sealed lids, an intermediate dispensing tank 3, a gas receiver 4, a cryogenic gas machine 5, a heat exchanger fluidizer 6, an evaporator 7, electrovalves 8, 9, 10 and 11, a sensor 12 pressure indicators 13 and 14 levels. The receiver 4, tanks 1 and 2, and liquefier 6 are connected by a gas pipeline 15. The fluidizer 6 is connected to the tank 3, which is located lower in level, by the cryogenic pipe 16. The tank 3 is connected by the cryogenic pipe 17 to the storage tanks 1 and 2. (The number of these tanks maybe more). The cryogenic gas machine 18, used for the initial filling of the dispensing vessel 3, through the air separation distillation column 19 and the valve 20 communicates with the expansion vessel 21, which, in turn, is connected by an cryogenic pipe 22 to the intermediate dispensing vessel 3. The compensation vessel 21 is provided an evaporator 23 and a fluid supply valve 24. A valve 25 is provided in the cryogenic pipe 22. A pressure sensor 12, a cryogenic gas machine 5, valves 8, 9, 10 and 11 and level gauges 13 and 14 are connected to the control system ( not shown), which contains the algorithm of work described below.

 The system operates as follows.

 The cryogenic gas machine 18 serves as the initial source of liquid nitrogen to the expansion vessel 21. It liquefies the air coming from the room atmosphere into the air separation distillation column 19. From the column 19, liquid nitrogen is discharged into the expansion vessel 21 through an open valve 20, and then after filling it, into the supply container 3. To do this, the valve 20 closes, the valve 24 opens, the pressure in the vessel 21 rises and the liquid nitrogen is transferred to the supply container 3. After the end of the transmission, the valves 24 and 25 are closed they are. These operations are carried out in manual mode.

 In the initial state, tanks 1, 2 and 3 are charged with liquid nitrogen to the maximum level, valves 9, 10 and 11 are closed, valve 8 is open.

 As liquid nitrogen evaporates in the tanks 1, 2 and 3, the pressure in the receiver 4 rises, which is detected by the sensor 12. If the pressure in the receiver and in the tanks 1, 2 and 3 reaches the maximum value set in the control system, the control system includes a cryogenic gas machine 5, the condensation of nitrogen begins in the fluidizer 6, liquid nitrogen flows into the tank 3. After reducing the pressure to a predetermined minimum value, the control system turns off the machine 5.

 In the event that the level of liquid nitrogen in the tank 1 (or 2) decreases to the minimum acceptable level fixed by the level indicator 13 (or 14), the control system includes a machine 5, which fluidizes nitrogen gas from the receiver 4 to reduce the pressure in the receiver to a minimum value, then machine 5 turns off, valve 8 closes, valve 9 and valve 11 on tank 1 open (or valve 10 on tank 2), liquid nitrogen enters the evaporator 7, when it evaporates, the pressure in tank 3 increases, liquid nitrogen is transferred from tank 3 to capacity 1 (or 2) until the maximum permissible level is reached, fixed by the level gauge 13 (or 14), then valves 9 and 11 are closed, valve 8 is opened.

 The proposed device has the following advantages.

 During operation of cryogenic equipment, periodic heating of biological storage facilities is not required to remove liquid oxygen that accumulates in ordinary cryogenic storage facilities using nitrogen as a cooling medium. This is due to the fact that during storage all of the nitrogen that has evaporated from the storage facilities is liquefied in a cryogenic refrigeration cycle and returned back to the tank. As a result of this, there is no need to constantly replenish biological storage facilities with new portions of liquid nitrogen containing liquid oxygen in the form of an impurity, the concentration of which increases as the liquid nitrogen evaporates from the vessel and can reach a dangerous value after some time.

 Since storage tanks do not require periodic heating, there is no need to move the biosamples stored in them from a heated vessel to another for temporary storage, and accordingly there is no danger of uncontrolled heating and contamination of samples. In this regard, the storage facilities do not have the means to ensure biological purity, laborious work is not carried out to transfer biosamples from one vessel to another, during which there is a risk of spoilage.

 The device has increased reliability in terms of stability of supply of liquid nitrogen (that is, there is no danger for it to suddenly stop the supply of liquid nitrogen by the supplier), since such supply after the initial filling of cryogenic equipment is not required.

 The reliability of the device is also increased, compared with a conventional cryogenic biorepository, due to the availability of a reserve source of liquid nitrogen (based on the installation for receiving liquid nitrogen), which, in case of failure of the main equipment, ensures the maintenance of the required temperature level of storage.

Claims (1)

 A cryogenic device for long-term storage of bio-products, consisting of a group of storage tanks, including a compensating vessel, an intermediate dispensing tank and a cryo-liquid distribution system, characterized in that the storage tanks are equipped with hermetically sealed lids, and the gas discharge lines from them are connected to the receiver reservoir and the working cavity of the automatically switched on cryogenic gas machine, the drain line of which is brought into the intermediate dispensing tank located below it, equipped with a car aticheskimi pressure lifting systems and individual distribution of cryogenic liquid storage tanks.