Tanks hermetic

Ampoules that have been sealed by fusion must be tested to ensure that a hermetic seal was obtained. The leaker test is performed by immersing the ampoules in a dye solution, such as 1% methylene blue, and applying at least 25 in. (64 cm) of vacuum for a minimum of 15 minutes. The vacuum on the tank is then released as rapidly as possible to put maximum stress on weak seals. Next, the ampoules are washed. Defective ampoules will contain blue solution. 

Fig. 12 tandem high-pressure canned-motor centrifugal pump of semi-hermetic specification with a compensation tank... 

Four auxiliary tanks can be coupled to and operated from the Vinyector s control panel. The tanks can hold solutions for deacidification, bleaching, or rinsing. This system, designed for small workshops with a few technicians, is obviously a slow one for this reason the Center uses only the basic leaf caster. An additional feature of the machine, again for small workshops, is that its chamber can be sealed hermetically and used for fumigation with, for example, commercial mixtures of ethylene oxide and carbon dioxide. 

The deodorized coconut oil flows down to the drop tank and holding chamber of the distilling column. Residence time in the deodorizer ranges from 1.5 h to 2 h. The oil from the column is withdrawn by a hermetically sealed and heat-resistant pump and conveyed to the economizer, which preheats the incoming deodorizer feedstock. The oil is cooled down to 50°C, at which temperature citric acid is added. Citric acid enhances the stability of oil by immobilizing iron and copper, which are pro-oxidants. (Note The deodorization step is omitted in the production of Cochin oil.)... 

This particular brand is hermetically sealed, which was an important consideration because of the switch s proximity to the tank. Also, the snap action switches in this model were potted (sealed). This in itself does not provide an appropriate level of safety, but since the system uses a low current, low voltage signal, we considered the switch to be adequate for our needs and safety concerns. Of course we cannot advise the use of such equipment. Any switches used in a system must meet the standards of your area AHJ. 

An alternative design which has the advantage of reduced periodic maintenance of the oil or liquid is the sealed type. The main tank is designed not to breath and is provided with a gas or vapour space between the top surface of the liquid and the underside of the tank lid. The lid is bolted onto the tank using a gas tight gasket, to form a hermetic seal. 

Self-cleaning clarifiers, in which the solids are discharged at intervals while the centrifuge is operating at full-speed (Fig. 20.12). They are available for both wort and beer clarification with throughputs of up to 600 hl/hr (370 brl/hr). The same machines used for beer recovery from fermenters and tank bottoms operate at up to 40 hl/hr (25 brl/hr). Many of these machines used for beer treatment are hermetically sealed so that neither carbon dioxide is lost nor oxygen taken up. 

Cast iron or steel pumps are recommended and can either be centrifugal, hermetic or those operating with solvent resistant mechanical seals. All vessels and intake lines, marked at the delivery point, should be clearly labelled with the name of the solvent. Regular, recorded inspection should be undertaken to ensure the integrity of the storage tank, pipes and pumps. 

Several principles of inert gas systems for tanks exist but the system adapted to the winery must be well designed. In particular, the installations mnst be perfectly airtight. Maintaining a slight overpressure is recommended in order to monitor for possible leaks. This method is essentially applicable to perfectly hermetic tanks. 

Installations have been specially designed for wine storage using inert gas. Metal tanks are connected together by gas lines, but the tanks can be isolated and individually maintained at a slight overpressure (100-200 mbar). This overpressure attests to the hermeticity of the tanks. It is verified by the manometer reading. 

Today, most red wines are fermented in tanks that can be closed when the carbon dioxide release rate falls below a certain level. The complete protection from air permits maceration times to be prolonged, almost as long as desired. The tank can be hermetically sealed by a water-filled tank vent (Figure 12.5) or simply closed by placing a cover on the tank hatch. In the latter case, the CO2 which covers the upper part of the tank disappears over time and the protection is not permanent. The tank should therefore be completely filled with wine or a slight pumping-over operation should be carried out twice a day to immerse the aerobic germs. 

Fig. 12.5. Hermetic water-tiUed tank vent allowing the release of CO2 from tank during fermentation without air entering...

A hermetic lid at the top of the tank. A water-filled tank vent (Figure 12.5) makes the tank completely airtight, while allowing the liquid to expand. 

After fermentation, pumping-over operations should be discontinued in hermetic, closed tanks to avoid oxygen exposure. In open tanks, pumping-over operations are continued. Extended macerations in partially filled tanks require a short pumping-over operation twice per day to immerse aerobic germs. 

In the traditional, quality-orientated European vineyards, the drawn-off wine was collected in small wooden barrels. The wooden fermentors were not hermetic enough to protect wine from contact with air. Concrete and stainless steel tanks have been recommended since their development, for wine storage during the completion phase of fermentation. This completion phase precedes barrel aging. The tanks must of course be completely full and perfectly airtight. 

The fuel tank is then emptied and again filled to 50% of its nominal volume. After being warmed to 40°C, the tank is hermetically sealed and the pressure in the tank is thus kept constant. During the subsequent test time of eight weeks, the maximum average fuel loss must not exceed 20 g/24 h of the test time [515]. 

The variable inductance probe consists of a doubly wound coil in a ceramic form [22]. The coil is inserted into a pipe well inside the tank and, as the liquid-metal level rises, the inductance of the coil changes. The change of inductance is detected in a bridge circuit, with the degree of unbalance being a measure of the level. This method has the advantage, especially important in handling radioactive fluids, that the system is hermetically sealed at all times. 

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