JPH07275741A - Centrifugal separator - Google Patents

Abstract

PURPOSE:To automatically and steadily remove the oil contaminant increasing the radiation of a lid as the lid is opened and closed by adding a mechanism to clean the inner surface of the lid at the opening of a vacuum vessel and to improve the precision in temp. control without using an expensive radiation pyrometer or a reflector. CONSTITUTION:A door 8 is opened when the centrifugal separator is used, a rotor contg. a sample is fixed to the rotating shaft of a driving device 3, then the door 8 is closed, and a vacuum vessel 7 is evacuated. The vessel 7 is then returned to the atmospheric pressure, and the sample is recovered. At this time, a gaseous oil remaining in the vessel 7 is condensed due to a sudden change and deposited on the inner surface of the door 8, etc. Further, the dust in the introduced atmosphere is got hold of by the oil. Accordingly, the cleaner 10b of a cleaning mechanism is pushed down by the door 8 against a spring 10d as the door 8 is opened, and the cleaner 10b is pressed on the inner surface of the door 8 by the reactive force. Consequently, the deposit on the door 8 is wiped off.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to heat insulation of a device such as an ultracentrifuge for controlling the temperature of a rotating body rotating in a container by cooling and heating by radiation heat transfer in a vacuum container. .

[0002]

2. Description of the Related Art The conventional ultracentrifuges have problems that they are expensive or have low temperature control accuracy. Each method and problems are shown below.

1) Radiant heat is covered by the cooling or heating ability of the inner container, and the temperature of the object to be temperature-controlled which is directly rotating is measured using a radiation thermometer. Is the temperature measurement accurate even if the radiant heat from the lid of the vacuum vessel directly enters the temperature controlled object?
Adjustment takes time and is expensive. In addition, due to recent freon regulations, cooling is being switched from freon refrigerators to electronic cooling using Peltier elements. This electronic cooling has a characteristic that the heat absorption amount is significantly reduced when the temperature difference between the heat absorption surface and the heat radiation surface is large. Therefore, the heat absorption amount is increased by the heat input from the lid of the vacuum container and the temperature of the cooling surface is increased. It is necessary to strengthen the heat dissipation system for electronic cooling to compensate for the rise in temperature on the cooling surface.
It will be more expensive. 2) As shown in FIG. 4, a thermally insulating reflecting plate is provided between the lid of the vacuum container and the inner container. Most of the reflection plates use a metal surface having a low emissivity for the surface of the vacuum container lid side, and reflect the radiant heat from the vacuum container lid.
In addition, the inner container side has a high emissivity coating and surface modification,
It may be radiatively cooled or heated by the inner container and may also be part of the temperature control surface for the temperature controlled object. Although the effect of radiant heat from the vacuum container lid can be made quite small, as shown in the enlarged view of FIG. 5, the mounting structure for maintaining the heat insulation of the reflection plate is complicated and the vacuum container lid itself becomes thicker, so the above 1) It is not so expensive, but expensive. 3) The external temperature or the temperature of the vacuum container lid is measured, the amount of heat incident on the rotating temperature-controlled object is estimated, and the control temperature of the internal container is corrected. If the emissivity of the vacuum vessel lid is constant, the radiant heat incident on the inner vessel can be almost calculated and calculated. Currently, it is the cheapest method, but as the equipment is used, the evacuation rate of the dirt on the lid of the vacuum container increases, and the radiant heat directly enters the rotating body that is the temperature-controlled object. It causes deterioration of control accuracy. When electronic cooling is adopted, the heat radiation system needs to be strengthened for the same reason as in 1) described above, which is expensive.

[0004]

As described above, in the prior art, it is expensive because a radiation thermometer is used because it is not affected by the radiation of the vacuum vessel lid, or a reflector is used to shield the radiation. Although relatively inexpensive, there was a problem that the temperature control accuracy was low.

An object of the present invention is to improve the temperature control accuracy by suppressing radiant heat input from the lid of the vacuum container without using an expensive radiation thermometer or reflector and to enlarge the heat dissipation system for electronic cooling. It is to provide an inexpensive vacuum container lid that is unnecessary.

[0006]

The problem is radiant heat input from the lid of the vacuum container. The radiant heat is proportional to the quadrature of the temperature difference and directly proportional to the emissivity. Since the temperature difference depends on the operating environment and the control temperature, it cannot be controlled without adding a new device. Therefore, the purpose is to keep the emissivity of the vacuum container lid low. The lid of the vacuum container of the ultracentrifuge is made of metal for both vacuum resistance and protection in case the rotor breaks. If the metal surface is not originally oxidized, the emissivity is sufficiently low at 0.05 to 0.1 depending on the degree of processing. Further, in order to prevent the metal surface from being oxidized, the low emissivity can be maintained by plating the surface with a metal that does not oxidize in a normal environment, and this is also done in the current apparatus. The main cause of high emissivity is dirt on the lid of the vacuum container. The cause of dirt on the vacuum container lid is that the vacuum pump oil, diffusion pump oil, and drive unit lubricating oil vapor that are generated when the vacuum container is evacuated are condensed every time the vacuum is returned to atmospheric pressure using the device. The oil deposited on the inner wall further deposits dust and the like in the air, and the oil itself oxidizes to increase the emissivity.

However, paying attention to the fact that the emissivity of the vacuum container lid is hardly affected by an extremely thin oil film generated by using the device several times, and the oil content of the vacuum container lid is wiped off every time the device is used. It is achieved by adding a mechanism.

[0008]

Since the vacuum container lid of the ultracentrifuge constructed as described above wipes off the oil content on the inner surface of the lid each time it is used, a low emissivity can always be maintained.

[0009]

The present invention will be described below with reference to an embodiment of the present invention. In FIG. 1, the rotating body 1 in which the sample 2 is inserted is rotated at a high speed by the driving device 4 in the inner container or the rotating chamber 3. Since the rotating chamber 3 controls the temperature of the rotating body 1, the temperature can be arbitrarily controlled by the cooling / heating device 5. A protector 6 is provided on the outer circumference of the rotary chamber 3 to prevent scattering of fragments when the rotary body is broken.
There is a vacuum container 7 composed of three members for maintaining a vacuum so that it does not generate heat due to friction with air when it rotates at a high speed, and its opening is covered with a vacuum container lid or a door 8.
The door 8 moves laterally on the door rail 9 as shown in FIG. 2, so that the rotating body 1 and the sample 2 in the rotating chamber 3 can be taken out. The cleaning mechanism 10 according to the present invention is provided between the door rails 9 slightly lower than the door 8. Figure 3
2, the cleaning mechanism 10 has a structure in which when the door 8 is opened, the cleaner 10b made of a material having an oil absorbing property is pressed against the inner surface of the door 8 by the spring 10d. When using the ultracentrifuge here, the user opens the door 8 and attaches the rotating body 1 into which the sample 2 is inserted to the rotary shaft of the drive unit 3, closes the door 8 and closes the inside of the vacuum container 7 with a vacuum pump or the like. Apply vacuum and start operation. At this time, since the pressure inside the vacuum container 7 becomes low, the lubricating oil of the driving device 3 and the oil of the vacuum pump are gasified and flow into the vacuum container 7. The user stops the rotation after operating for a predetermined time, and returns the inside of the vacuum container 7 to the atmospheric pressure in order to recover the rotating body 1 and the sample 2. At this time, the oil gas remaining inside the vacuum container 7 is condensed and liquefied due to a sudden change in atmospheric pressure and adheres to the inner surface of the door 8, the inner surface of the vacuum container 7 and members inside the vacuum container 7 and is also introduced. Dust in the air is trapped in the attached oil. The user opens the door 8 in order to collect the rotating body 1 and the sample 2. At this time, the cleaner 10b of the cleaning mechanism is pushed down by the door 8 and the spring 1 is released.
0d is compressed and the reaction force causes the cleaner 10b to move to the door 8
The oil content and the dust in the air that are pressed against the inner surface of the door 8 and adhered to the inner surface of the door 8 can be absorbed and wiped off, and the emissivity of the inner surface of the door 8 can be kept low.

[0010]

According to the present invention, since oil stains that increase the emissivity of the vacuum container lid of the ultracentrifuge can be constantly removed, a reflector for reducing the radiant heat of the vacuum container lid is unnecessary. . Also, since the emissivity of the vacuum container lid can always maintain a stable low value, the temperature change of the rotor due to direct radiant heat input from the vacuum container lid to the rotor is slight and stable, so it is inexpensive. Temperature measuring means can be used.

[Brief description of drawings]

FIG. 1 is a partial vertical cross-sectional view showing an ultracentrifuge according to the present invention.

FIG. 2 is a partial vertical cross-sectional view showing an ultracentrifuge according to the present invention.

FIG. 3 is an enlarged view showing an oil wiping mechanism according to the present invention.

FIG. 4 is a cross-sectional view showing a vacuum container lid using a reflection plate according to the related art.

FIG. 5 is an enlarged sectional view showing a vacuum container lid using a reflection plate according to a conventional technique.

[Explanation of symbols]

1 is a rotating body, 2 is a sample, 3 is a rotating chamber, 4 is a driving device, 5
Is a heating / cooling device, 6 is a protector, 7 is a vacuum container, 8 is a door, 9 is a door rail, 10 is a cleaning mechanism, and 10 is a cleaning mechanism.
a is a cleaning mechanism holding portion, 10b is a cleaner, 10
c cleaner support member, 10d spring, 11 reflector, 1
Reference numeral 2 is a heat insulating washer, and 13 is a fixing screw.

Claims (1)

[Claims] 1. An apparatus for controlling the temperature of an object placed in the inner container by controlling the temperature of the inner container by having an inner container for cooling or heating in a vacuum container,
In a centrifuge in which a part or the whole of the lid of the opening of the vacuum container for inserting and removing the object directly opposes the cooling and heating surface of the inner container and the temperature-controlled object, inside the lid of the opening of the vacuum container. A centrifuge characterized by having a mechanism for cleaning the surface.