JPS6050485B2 - Filter element for oil mist separation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an oil mist separation filter element for separating and removing oil mist floating in gas from the gas.

The gas discharged from the compressor contains a large amount of oil mist, and a mist separator as shown in FIG. 1, for example, is used to separate and remove this mist.

In the figure, 1 is a container housing the filter element 1, 3 is a gas inlet of the container, and 4 is a gas outlet of the container. The filter element 2 shown in the figure has a hollow cylindrical shape made of an annular fiber-filled layer 6, and its hollow lower end is connected to a disk 5.
The upper end of the hollow part is fixed to the container so as to communicate with the gas outlet 4. Gas entering from the inlet 3 flows from the outer circumference to the inner circumference of the fiber-filled bed 6 in the direction of the arrow. The oil mist in the gas coagulates and grows while passing through the fiber packed bed 6, becomes large oil droplets, separates from the gas, and accumulates in the bottom 7 of the hollow part of the filter element 1. The accumulated oil is removed through an oil drain pipe 8. A throttle 9 is provided in the middle of the drain oil pipe to adjust the amount of drained oil and prevent gas from leaking together with the drained oil. Conventionally, a type of filter element in which a filled layer of glass fibers is held down by perforated plates on both sides has been often used.

Glass fiber is characterized by its low price and high heat resistance. For example, in the case of an air compressor, the discharge temperature of the gas from the compressor can be close to 150°C, and even if the gas temperature is low, the oxidation of the oil attached to the fiber layer under high pressure can sometimes occur. The temperature can reach over 300°C.
Furthermore, even if the gas temperature is low, when the gas blows through the fiber layer, static electricity may be generated due to friction between the gas and the fibers, resulting in sparks. For these reasons, the filler used in the filter element must be non-flammable.

General chemical fibers have poor heat resistance and are not suitable as filter elements, and for this reason glass fibers have often been used. Conventionally used glass fibers had a limited ability to separate oil mist, and the only way to improve the separation ability was to increase the size of the device.

Recently, there has been a strong demand for miniaturization of oil mist separators, and an alternative fibrous material with high separation ability is needed.

An object of the present invention is to improve the separation performance of a filter and to reduce its size.

A feature of the present invention is that ceramic fibers having adsorption properties are used as a filter layer of a filter element for oil mist separation, and woven fabrics are arranged on both interfaces of the ceramic fiber layers.

An embodiment of the present invention will be described below with reference to FIGS. 2 and 3. FIG. 2 shows only the filter element, and in the same figure, reference numeral 10 is a perforated plate wound into a cylindrical shape, and a wire mesh layer 11 is wound around the outer circumferential side of this perforated plate.

Further, a woven fabric 12 is wound several times around the outer circumferential side of the wire mesh layer 11. A ceramic fiber layer 13 is wound around the outer periphery of the multilayer cylinder thus obtained, and the ceramic fiber layer 13 is wrapped around the outer periphery of the multilayer cylinder thus obtained. Aiba layer 1
After wrapping the woven fabric 14 several times around the outer peripheral surface of the perforated plate 1
Hold with 5. The ceramic fiber used here is
It is a silica*8 alumina-based material that has adsorption properties, and is made into fibers using the following manufacturing method. The so-called plowing method involves ejecting a trickle of molten material (silica alumina) into a high-speed air current (steam or air), and splitting and stretching the molten material using the high-speed air current, or the plowing method, in which the molten material is blown onto the side of a rotating disk. The material is dropped and made into fibers by a so-called spinning method that utilizes centrifugal force.

Both ends of the thus wound multi-layered filling layer are held down by lid plates 16 and 17, respectively.

These lid plates 16 and 17 are circular plates with a hollowed out center, and their inner and outer edges 18 and 19 are bent and fitted and fixed to the inside and outside of the multi-layered filling layer.
The method of using the filter element constructed in this way is the same as that shown in FIG. 1, in which the lower end of the hollow portion is closed, the upper end is communicated with the outlet of the container, and the filter element is fixed to the upper end of the container.
Gas containing oil mist flows inward from the outer periphery of the filter element in FIG. 2 in the direction of the arrow.

When the gas passes through the ceramic fiber layer 13, the oil mist in the gas coagulates and grows together to form large oil droplets.
These oil droplets separate from the gas and are removed when the gas exits the hollow part of the filter element.

A filter element using ceramic fibers having the structure shown in Fig. 2 and a filter element using glass fibers having the structural dimensions shown in Fig. When the oil mist separation performance was compared by incorporating each into a mist separator and passing the discharge gas from an oil-cooled compressor, the results shown in the following table were obtained. The numbers in the table are the oil mist concentrations in the gas after passing through the mist separator. In this way, the separation performance of ceramic fibers and fibers is much better than that of glass fibers. The particularly good performance of ceramic fibers is due to their inherent ability to adsorb oil mist.

As mentioned above, ceramic fiber has good properties as a filter material for oil mist separation, but the fiber itself does not have the same toughness as glass fiber.

For this reason, the interface between the fiber layers is pressed with a woven cloth to prevent the ceramic fibers from scattering due to the gas blowing through. Further outside the woven fabric, the packed layer is supported by a perforated plate to prevent it from being deformed by the wind pressure of the gas, but if the woven fabric and the perforated plate are brought into close contact with each other at this time, the following problems occur.

The aperture ratio of the perforated plate is generally about 20% to 30%.
When a woven fabric is brought into close contact with such a perforated plate, the effective portion of the woven fabric through which gas passes is only the portion corresponding to the holes of the perforated plate. Gas cannot pass through the woven fabric that is in close contact with the non-porous portion of the perforated plate. The woven fabric used here is a very fine woven fabric that prevents the passage of fibers with a diameter of several microns. When a mixed fluid of oil and gas passes through a woven fabric whose effective area is only the same as the porosity of the perforated plate, not only does the pressure loss of the gas increase, but the woven fabric also gets clogged quickly. This tendency is particularly remarkable on the downstream side of the packed bed. On the upstream side, the wind pressure causes the woven fabric to be somewhat separated from the perforated plate, so the above problem does not occur as much. The wire mesh layer 11 shown in FIG. 2 is provided to solve this problem.

By placing several layers of wire mesh between the woven fabric and the perforated plate, the woven fabric and the perforated plate are prevented from coming into close contact with each other, allowing gas to flow uniformly throughout the woven fabric, reducing pressure loss and clogging of the filter element. can be reduced. FIG. 3 shows another embodiment of the invention.

In the figure, 20 is a cylindrical container, and 21 and 22 are gas inlets and outlets, respectively. 23 is a perforated disc, 24 is a woven fabric, 27 is a wire mesh layer, and 28 is a perforated disc.

Gas containing oil mist enters from the inlet 21 as shown by the arrow, passes through the packed bed, becomes clean, and exits from the outlet 22 as shown by the arrow. The oil droplets coagulated and grown in the packed bed are discharged from the oil drain port 29. The functions of the perforated disk, woven fabric, ceramic fiber layer, wire mesh layer, etc. in this embodiment are the same as the corresponding elements in FIG. In other words, ceramic fibers with good oil mist separation performance are held down by woven cloth to suppress scattering of the ceramic fibers, and a wire mesh layer is inserted between the woven cloth and the perforated plate that supports the fiber layer on the downstream side. Prevents adhesion with the perforated plate.

As described above, since the present invention uses ceramic fibers as the filter material, it is possible to obtain an oil mist separator with much better separation performance than conventional filters using glass fibers.

This makes it possible to downsize the oil mist separator. In addition, by placing a wire mesh layer between the woven fabric that presses the fiber layer and the perforated plate that supports them as in the example, it is possible to prevent the woven fabric and the perforated plate from coming into close contact with each other, prevent clogging of the woven fabric, and Gas pressure loss can be reduced.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of a hollow cylindrical filter element, Figure 2 is an illustration of a hollow cylindrical filter element.
The figure is an explanatory diagram of one embodiment of the filter element of the present invention,
FIG. 3 is an explanatory diagram of another embodiment of the filter element of the present invention. 10, 15... Perforated plate, 12, 14...
Woven fabric, 13...Ceramic fiber layer.

Claims (1)

[Scope of Claims] 1. In a device that separates and removes oil mist from gas by passing gas containing oil mist through a filter layer, the filter layer has adsorption properties and is woven on both interfaces. A filter element for oil mist separation characterized by being composed of ceramic fibers with cloth arranged on them. 2. In a device that separates and removes oil mist from gas by passing gas containing oil mist through a filter layer, the filter layer is made of a ceramic fiber having adsorption properties and having woven fabric arranged on both boundary surfaces. At the same time, a perforated plate is arranged on the upstream side of the woven fabric located on the upstream side of the gas flow passing through the ceramic fiber layer, and a wire mesh layer is placed on the downstream side of the woven fabric located on the downstream side. A filter element for oil mist separation characterized by perforated plates arranged in order on the downstream side of a wire mesh layer.