“Do not handle liquid nitrogen if you have not read all safety standards”
Suggested Guidelines for the Use of Liquid Nitrogen Containers:
For safe handling of liquid nitrogen containers need to have a little care and common sense.
First, it is essential to know some properties of liquid nitrogen. (NL)
- It is extremely cold, at normal atmospheric pressure is 196 ° below zero.
- Produce a large accumulation of gas. One liter of NL, vaporizes about 708 liters of nitrogen gas.
Any of these properties can cause personal injury or damage to other items nearby.
Nitrogen gas is colorless, odorless,
tasteless and … DEADLY!
By reducing the oxygen concentration in the air can cause asphyxiation.
Due to its properties can not be detected by sight, taste and smell, and therefore, can be inhaled like air.
‘s why the NL must be stored and used in well ventilated areas.
as liquid nitrogen “evaporates”, the resulting nitrogen gas displaces the normal air, breathing air with less than 18% oxygen can cause dizziness or fainting … death.
Nitrogen is Invisible:
When liquid nitrogen is exposed to air, the vapor cloud observed is the condensation of water and other elements not nitrogen gas. The gas is invisible, but a few simple precautions and serve to protect.
Cryobiological containers must be filled very slowly to avoid tensions resulting from a sudden temperature change, which is caused by rapid filling thereof.
- Minimum filling time: 30 minutes.
- Containers should always be upright.
Put the container lying can cause leakage or damage, as well as in a horizontal position, is likely to be subject to strong vibrations, resulting in negative impacts on the vacuum insulation system.
Gas Liquid Nitrogen extremely cold one:
NL Handle with extreme care, this contact with the skin can cause serious injuries from freezing of epithelial tissues.
- Try to avoid frozen NL objects come into contact with your skin.
An object can be cooled NL attached to your skin and you try and pull it apart.
The hearing may be damaged when nitrogen droplets (spray) come in direct contact with the cornea.
- Always use tweezers or spoons for removing any container object.
- Protective clothing can reduce risks in the handling of liquid nitrogen.
Insulating gloves or thick leather should be used whenever handling an object that has been in contact with the NL. We recommend the use of gloves mitten type so they can be removed quickly if liquid nitrogen falls within them.
wear glasses to prevent spray damage the eye.
If anyone working with NL suffers dizziness or loss of consciousness, should move it to a completely ventilated and call your doctor.
If you have difficulty aplíquesele rerspirar oxygen.
When breathing stops, apply artificial respiration then oxygen. Keep person warm as possible and quiet until the doctor arrives.
If the person is splashed or exposed to the NL, the affected area should be restored to the body temperature, 37 ° C, as fast as possible.Loosen clothing, belts, bracelets, rings, etc., which may impede blood circulation to the affected area and wash or immerse the affected area in hot water at 42 ° C. No water must be heated above 45 ° C. Protect the affected area from further injury or infection and go to the doctor.
should not massage the affected area, trying to revive the movement and not allowing the affected person smoking and drinking alcohol.
Liquid nitrogen control in Termo:
- Do not cover the mouth of the container tightly.
The containers are designed to operate with little or no internal pressure. Using any pressure controller or valve that prevents gas venting, creates a pressure that can cause damage or even crack the container, including the freezing accumulated in the neck may interfere with proper ventilation. The containers should be periodically checked by qualified personnel to avoid such obstructions.
To safely operate the container should be used only neck cap original or approved accessories for closing the tube neck.
thermo Remove the cap always upright, prevent rubbing against the neck and thus will reduce the premature wear .
- Decanting the liquid nitrogen with caution.
The primary risks NL transfer from one container to another are spilling and splashing. To accomplish avoid these risks is necessary to use special funnels (with mouths partially covered).
Moreover, this form of decanting occurs over time the most important and irreversible damage to the containers, neck breaking, only support between the liner and the outer shell.
Based on the above it is necessary to use the pressurized transfer device that works at a rate of 2 liters per minute.
- Never overfill containers.
Overfilling containers above the specified level will tend to spill from NL, and exposes the neck to produce extra strains shortening the useful life of the container.
- Keep the containers in places, clean, dry and ventilated.
Wash the containers with warm water or with very light detergent solution and then wipe dry.
caustic cleaning items, detergents or chemicals that could cause corrosion should not be used in cleaning them.
- Transport containers carefully.
Closed trucks or vans are not recommended for container transport cryobiological. It requires the use of vehicles ventilated to prevent the accumulation of nitrogen gas.
For transport by car:
- Place them in the back seat, aprovech ‘m a seatbelt to secure.
- Passing said cross belt through the loops of the container.
- Avoid direct sunlight.
- Keeping the windows open side container moved.
- Ensure the thermos upright, moving the seat back until the back of this take contact with the container.
- When transporting more than one container, take the same precauc.iones Pull and prevent contact between them.
For transport in trucks:
- For reasons of obtaining maximum safety for the carrier, it is desirable that the heat is placed in a box (wood or aluminum) fitted lid, lined inside with Styrofoam or foam to absorb impact that this coating vibration or shock.
- The bounding box is secured with straps, as far forward as possible dela cab, as this place is the slightest movement.
- In case of not having a container box, must be placed between the flask and the floor of the vehicle body a piece of foam rubber, as well as between the side where it is secured.
- When transporting more than a thermos, act in the same direction and also put foam between them.
Liquid nitrogen control within the Termo:
1. In order to check the level of NL, cryobiological container models are delivered with plastic meter. Proceed as follows: Remove the lid of the thermos. Carefully place the rule to the bottom of the flask (must be very careful with the over-thickness due to eventual delivery of baskets). Leave Rule 3-4 seconds in the background. Take it out and stirring at room temperature. After the condensation of air humidity indicates the height (in the rule) of the amount of liquid remaining in the container.
2. If by accident the container is totally covered with frost, means that the gap between the walls is broken, and therefore, the nitrogen must evaporate very quickly. If you have products or biological material in the container, they should move to another as quickly as possible. If, however, there is a small plate of frost should be monitored in the following days, the container and the level of nitrogen.
3. In case of detecting a significant and rapid deterioration in the functioning of the container should be put out of service immediately. In no way should act on it, but should consult with the selling agent, who if necessary will contact the manufacturer.
Nitrogen Care Termo down:
When some heat is out of service for not containing, at the time, biological material, proceed as follows to ensure perfect condition:
1. If nitrogen is only loosely, let this evaporate.
2. Remove the cover and the heat begins to take temperature.
Completed the above steps can be observed that the amount of condensate present in the background and inner walls of fear is considerable.
If we put the cover and we kept the heat in these conditions provocaríamos surely pinholes and perforations after it would damage irreversibly.
How to proceed?
1. Remove the canisters inside and placed inside the thermos 300cc 96 º alcohol.
2. Achieve, with soft undulating movements that come in contact with alcohol around inside the thermos.
3. Dump excess alcohol stomach putting the thermos.
4. Once drained placed in a box (always face down) and allow complete drying. Put in this position long enough to leave no moisture.
5. Achieving this, bring the heat to its upright position and replace the cover.
6. The canisters must be washed and dried thoroughly before reintroducing it into the thermos.
If it finds that at the bottom of the flask are many black spots, it is advisable to immediately bring the heat to the authorized service for the purpose of performing a thorough cleaning.
This will prevent stains become perforations aluminum oxide product introduced therein.
SEMEN AND NITROGEN TERMO
Maintaining the temperature of frozen semen:
To perpetuate the maximum fertilizing capacity of frozen semen, the temperature should not exceed -138 ° C.
If the temperature reached 80 ° C, their fertility would be reduced irreversibly.
Semen Transfer to a Thermo Other:
The large surface area and relatively small volume of diluted semen straws content leads to rapid heat exchange.
straws exposure at 20 ° C / 21 ° C (room temperature) produces rapid temperature changes inside.
It has been shown that exposure to 20 ° C for one minute, of 0.25 ml French straws a loss of 81.5% in sperm motility.
It is, moreover obvious that the straw shall not be exposed to ambient temperature for decanted or deposit the semen. Therefore, the packaging of these in gobelets (plastic cylinder) is effective, as it keeps the straws dipped in nitrogen, preventing the temperature rise when carrying the canisters to the mouth of the thermos.
Semen menera conditioning this may be exposed to ambient temperatures of 30 ° C, for a period of one minute, at least, without loss of motility.
Recommendation: The straws should be trasvasadas and distributed to their respective gobelets, since these ensure immersion in liquid nitrogen (-196 ° C).
Repeated exposure during removal of semen in the insemination
As we stated above, each time take the straw into the neck of the flask, sperm fertility may be impaired.
As indicated in Fig. No. 1, the temperature in the flask neck varies depending on where they take the same.
As can be seen, is in this point where the highest temperatures are recorded. The damage caused by repeated exposure (canisters rises to the mouth of the flask) is additive.
damage produced in the first straw to be drawn is less than the damage caused, for example, number 20 in the straw is removed as the temperature is gradually rising, having no time to go back to 196 ° C (see fig. No. 2)
This occurs when the level of nitrogen from a thermos of 32 liter capacity does not exceed 14 cm. (Measured with the plastic ruler). In his first exhibition the straw is exposed to -120 ° C, temperature above critical (-130 ° C).
If to this is added within extraction of 1 to 1.30 minutes between straw and straw, the temperature exposure of the following will even more, and therefore even greater deterioration.
If the level of nitrogen in the flask exceeds 14 cm, the temperature at the bottom of the neck will be below the critical, thus reducing the risk of damage.
The temperature which is reached during exposure is dependent on the neck of the following:
1. Height at which the semen is taken. Do not exceed the extent possible, the lower third of the neck of the flask (-140 ° C to -160 ° C)
2. Exposure time. Do not stay with the canister in the level above, for more than 10 seconds between each shot of straw. If necessary the use of more time, reintroduce the canister to the bottom of the flask, gobelets nitrogen load and raise the straw again to continue the task.
3. Nitrogen level of heat. Maintain above 14 cm. Always remember that lower levels compromise the optimum working temperature on the mouth of the thermos.
4. Range of exhibitions appropriate level of nitrogen, can remain safely in the neck of the flask, until a minute.
Insist inseminator to perform a minimum exposure time and increase the interval between exposures when the nitrogen level is not optimal.
When semen raises its temperature of -196 ° C to -80 ° C, ALTERATION ARISING irreversible.
Vet. Gabriel A. IORIO