Clog indicating device in a dust collector

A clog indicating device indicating clogging of a dust collecting filter in a dust collector is disclosed. The dust collector includes on an upper region of its casing an exhaust port opening upward, and a cover member is mounted interspatially above the exhaust port. A colored indicating float is so located as to be movable upward between the exhaust port and the cover member due to pressure of an air exhausted from the exhaust port. Clogging of a dust collecting filter is indicated according to a degree of exposure or a position in an up and down direction of the indicating float between the exhaust port and the cover member.

CROSS REFERENCE TO RELATED APPLICATIONS

The Present application claims priority from Japanese Patent Application No. 2011-209531 of Sakuragi et. al., filed on Sep. 26, 2011, the disclosure of which is hereby incorporated into the present application by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a clog detecting device that indicates clogging of a dust collecting filter in a dust collector for collecting dust laden fluid such as dust laden oil mist (including oil smoke) generated in a machine tool or the like in a shop.

2. Description of Related Art

In a shop doing machine work, machine tools generate dust laden oil mist or the like. If left untreated, the oil mist not only makes working environment of the shop worse by causing bad odor in the shop, intrusion of the dust laden fluid into equipment and its control panels and dirt of walls, but also makes the floor of the shop slippery, which may cause fall of operators.

For this reason the dust laden fluid is required to be collected by a dust collector steadily and efficiently. To this end, such equipment as machine tools generating dust laden oil mist are usually provided with a dust collector that collects dust laden fluid with a dust collecting filter.

As the dust collecting filter collects the dust laden fluid, it is clogged due to collected dust laden fluid, which turns down collection efficiency of the filter and lets uncollected dust laden fluid released in the shop, thus making the working environment worse as described above.

This must be solved by frequent maintenance and inspection of the dust collecting filters, but it is difficult for a busy shop worker to watch the filters all of the time and clean or replace the filters as soon as they are clogged. JP 5-285325 A and so on discloses a device for monitoring clogging of a dust collecting filter in order to cope with such circumstances. The device includes in a suction chamber a pressure sensor for detecting a suction pressure of a blower for dust collection such that a detection signal is fed and clogging of a filter is announced when the suction pressure in the suction chamber surpasses a predetermined pressure.

However, in addition to electric sensing by the pressure sensor, the above conventional clog monitoring device also uses a temperature sensor for monitoring clogging of the filter. Since the device monitors clogging by means of a temperature signal as well as a pressure detection signal, the device has a complicated structure with the sensors and their detection circuits, and costs a lot of money for manufacturing. Further, the device requires maintenance and inspection for the sensors and detection circuits.

There is also known a clog indicating device including a damper pivotally supported at an exhaust port of the dust collector, an index needle mounted on a rotary shaft of the damper such that clogging of a filter is indicated by the index needle when a rotation angle of the damper is reduced.

However, although the index needle is mounted on a lateral of the exhaust port of the dust collector, the needle is very thin and is not easily viewable in a large shop, therefore it is not easy for operators to notice of clogging.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a clog indicating device in a dust collector that has a simple structure and is capable of indicating in an easily viewable fashion. The object of the invention will be achieved by a following clog indicating device in a dust collector:

The clog indicating device for indicating clogging of a dust collecting filter in a dust collector includes a cover member mounted interspatially above an exhaust port of the dust collector which port is located on an upper region of a casing of the dust collector and opening upward, and a colored indicating float that is movable upward between the exhaust port and the cover member due to a pressure of an air exhausted from the exhaust port. Clogging of a dust collecting filter is indicated according to a degree of exposure or a position in an up and down direction of the indicating float between the exhaust port and the cover member.

With this invention, the clog indicating device is easily constructed by locating the indicating float and cover member at the exhaust port of the dust collector, and the clog indicating device is capable of indicating clogging of dust collecting filters in an easily viewable fashion by the colored indicating float, at low cost. Further, since the device of the invention does not require any sensors or detecting circuit, it can be manufactured inexpensively, does not require maintenance and inspection, and rarely goes out of order.

The above clog indicating device may also be so configured that the support shaft is raised vertically at a center of the exhaust port and inserted through a through hole formed at the center of the indicating float to support the indicating float in such a manner that the indicating float is movable in an up and down direction, the cover member is mounted on top of the support shaft, and that the indicating float moves up and down along the support shaft according to a pressure of an air exhausted from the exhaust port.

With this configuration, the indicating float is movable in an up and down direction in a steady fashion according to the degree of clogging of filters with a relatively simple structure. Moreover, since the support shaft penetrates the center of the indicating float such that the indicating float can slide up and down along the support shaft, the indicating float is movable steadily up and down according to clogging of the filters to indicate clogging of the filters.

Furthermore, it is desired that the indicating float is fabricated of foamed synthetic resin or of a hollow synthetic resin body so as to be light. This configuration will make pressure loss in the exhausted air from the dust collector minimum.

DESCRIPTION OF PREFERRED EMBODIMENTS

A preferred embodiment of the present invention is described below with reference to the accompanying drawings. However, the invention is not limited to the embodiments disclosed herein. All modifications within the appended claims and equivalents relative thereto are intended to be encompassed in the scope of the claims.

FIGS. 1 to 4show a dust collector that collects dust laden fluid such as oil mist (including oil smoke), which contains fine dust generated in a machine tool in a machine shop.

Schematically, the dust collector is comprised of a generally rectangular parallelepiped casing1provided with a suction port2on the front. The casing1internally includes a main filter5as a dust collecting filter, a suction chamber3communicating with the suction port2, an aspiration chamber8communicating with the suction chamber3, an aspiration device10mounted on a back side of the casing1such that a fan11is located in the aspiration chamber8, an exhaust chamber17that is located above the suction chamber3and aspiration chamber8and partitioned from the suction chamber3and aspiration chamber8with a partition wall16, and an exhaust port19located on top of the exhaust chamber17. Further, a clog indicating device20is so formed as to protrude upward from the exhaust port19for indicating clogging of the dust collecting filter.

The casing11is formed into a generally rectangular parallelepiped box, and has a suction port cover1aon the front side. The cover1ais detachably secured to the front side with fixing screws and has the suction port2at the center. As shown inFIG. 4, a baffle plate4and a main filter5are located in the suction chamber3communicating with the suction port2. The baffle plate4receives a dust laden fluid taken into the dust collector with its metal louver and collects oil mist, fine dust or the like contained in the fluid as preprocessing. A drain29is connected to a bottom wall of the suction chamber3for letting out dust laden fluid such as oil.

As shown inFIG. 4, the main filter5is comprised of a cartridge box7and a plurality of demister6aand/or dust collecting filter6bset in the cartridge box7in layers. The casing1is provided on both lateral sides with a side cover1b/1cwhich are removably fixed to the lateral side with simple screws, such that the main filter5, i.e., the cartridge box7, the demister6aand filter(s)6btogether, may be easily taken out by removing either one of the side covers1b/1c.

The aspiration chamber8communicating with the suction chamber3is formed into a drum. A drum filter13is mounted around an outer circumference of the aspiration chamber8, which serves as a dust collecting filter. The aspiration chamber8adjoins the suction chamber3, and between the aspiration chamber8and suction chamber3is a partition wall9provided with a round opening. A fan11of the aspiration apparatus10is inserted into the aspiration chamber8from the back side of the casing1. The fan11is fixed to a rotary shaft of the motor12, and the motor12is secured to the backside of the casing1. The aspiration apparatus10runs the fan11and aspirates a dust laden fluid toward the aspiration chamber8from the suction chamber3, and forwards the fluid toward the exhaust chamber17, which is located there above, through the drum filter13arranged around the aspiration chamber8.

As shown inFIG. 4, the drum filter13is comprised of a filter support15which is secured inside the casing1and formed into a tubular net and a flexible sheeted filter, such as a cloth like filter or a nonwoven fabric filter, mounted around the filter support15. The filter support15is mounted on the partition wall9of the aspiration chamber8. The flexible sheeted filter can be easily replaced by removing the side cover1bor1cof the casing1. A fluid aspirated into the aspiration chamber8by running of the fan11of the aspiration apparatus10is forwarded to the exhaust chamber17located outside of the aspiration chamber8, through the drum filter13.

The exhaust chamber17extends from a circumference of the aspiration chamber8to an upper region of the casing1. As shown inFIG. 4, a discharge filter18is located at an upper region of the exhaust chamber17, and an exhaust port cover19ahaving an exhaust port19is located above the discharge filter18. The discharge filter18is formed of a filter element which is capable of collecting fine mist and dust of about 0.3 to 2 μm.

As shown inFIG. 1, the exhaust port19is so formed as to open vertically upward. A dust laden fluid sucked in via the suction port2passes through the main filter5in the suction chamber3, the drum filter13mounted around the aspiration chamber8and the discharge filter18while being freed from oil mist, fine dust and so on, then the filtrated air is exhausted upward via the exhaust port19. Although the discharge filter18illustrated inFIG. 4is a single-layered simple filter, it may alternatively be replaced with a high performance filter which is a multi-layered fine fiber cloth-like filter element.

As the main filter5, drum filter13and discharge filter18get clogged due to collected oil mist and fine dust, the flow rate and pressure of the exhausted gas turn down. Above the exhaust port19, there is mounted a clog indicating device20that indicates clogging of the filters using the decrease of the flow rate and pressure of the exhausted gas along with clogging of the filers.

Referring toFIGS. 5 and 6, the clog indicating device20includes a cover member23that is interspatially mounted above the exhaust port19and a colored indicating float21that is movable upward between the exhaust port19and the cover member23due to a pressure of a gas exhausted from the exhaust port19. Clogging of a dust collecting filter is indicated by the degree of exposure or by the position in an up and down direction of the indicating float21between the cover member23and the exhaust port19.

A support shaft22is raised vertically at the center of the exhaust port19, and the cover member23is mounted on top of the support shaft22for housing the indicating float21. The support shaft22is so configured as to be vertically secured to a metal mesh24arranged inside the exhaust port cover19awith fixing screws or the like, and therefore, the clog indicating device20can be mounted on an existing dust collector as long as the dust collector has an exhaust port that exhausts upward.

The indicating float21is fabricated, by way of example, of foamed synthetic resin or formed into a hollow body from synthetic resin so as to be considerably light. The float21includes at the center a through hole running through vertically such that the support shaft22goes there through and the float21is supported by the support shaft22in an up-and-down movable manner. As best shown inFIG. 6, the support shaft22is provided at its intermediate low region with a holder (washer)25. The holder25holds the indicating float21, which would otherwise slide down under its own weight, at an adequate intermediate exposure position. As best shown inFIG. 4, the holder25is so positioned as to hold the indicating float21at such a position that an adequate gap is formed between the exhaust port19and the indicating float21and the exhaust port19is open and air-releasable even when the float21is at the down end position.

The indicating float21is colored in an appealing color such as red, at least on the outer circumference. In a normal exhaust condition, the float21is pushed up enough to go inside the cover member23, and the float21appears from underneath the cover member23due to decrease of the exhaust flow rate or the like. When there is no exhaust from the exhaust port19, the indicating float21comes down under its own weight and rests on the holder25, above the exhaust port19.

That is, the indicating float21moves vertically in accordance with the flow rate and pressure of the exhaust from the exhaust port19. When the main filter5, drum filter13and/or the discharge filter18is clogged with oil mist and fine dust, the flow rate and pressure of the exhaust from the exhaust port19turn down, and accordingly the indicating float21appears from underneath the cover member23and indicates clogging of the filter(s).

Operation of the clog indicating device in a dust collector thus configured is now described. The dust collector is installed on or adjacent to such a machine tool as a machining center in a machine shop. An exhaust duct communicating with the machine tool is connected to the suction port2. When the dust collector is not actuated and there is no exhaust, the indicating float21is held by the holder25above the exhaust port19.

When the motor12of the aspiration device10is actuated to run the fan11, the dust collector aspirates dust laden fluid to the aspiration chamber8via the suction chamber3and diffuses it in a radial direction, such that the fluid is forwarded to the exhaust chamber17.

More specifically, dust laden fluid containing oil mist (including oil smoke) and fine dust, which the machine tool generates, enters into the suction chamber3via the suction port2, and hits the baffle plate4firstly. At this time liquefied oil as well as larger dust are removed from the fluid and fall down. Then the dust laden fluid passes through the demister6aand dust collecting filter6bof the main filter5, and is freed from oil mist and fine dust.

The fluid is then aspirated into the aspiration chamber8from the suction chamber3, diffused radially due to running of the fan11, and passes through the drum filter13and forwarded to the exhaust chamber17. At this time the drum filter13collects oil mist and finer dust further, and the air freed from oil mist and fine dust in the exhaust chamber17passes through the discharge filter18and is exhausted upward from the exhaust port19. The exhausted air pushes up and lifts the indicting float21from the position above the exhaust port19, and the operating condition of the dust collector is indicated by the way the indicating float21floats.

If the main filter5, drum filter13and discharge filter18of the dust collector have no clog, the exhausted air has sufficient flow rate and pressure to push up the indicating float21to the top end position such that it is housed inside the cover member23and kept in that state as shown inFIG. 6. That is, when the dust collecting filters have no clog and functions normally, the indicating float21is covered by the cover member23and is not visible.

In contrast, when the main filter5, drum filter13and/or discharge filter18are/is clogged, there arises pressure loss in the exhausted air according to the degree of clogging, and the flow rate and pressure of the air exhausted from the exhaust port19turn down. Accordingly the indicating float21having been pushed up inside the cover member23comes down according to the degree of clogging, and the red (or colored) float21appears between the cover member23and the exhaust port19.

Thus, an administrator of the machine shop can build an awareness of clogging of dust collecting filters easily and surely by seeing the degree of emergence of the indicating float21. At recognition of clogging, the administrator can clean or replace the main filter5, drum filter13and so on, and when the filters are thus unclogged, the indicating float21of the clog indicating device20is pushed up again by the exhaust with sufficient flow rate and pressure, and is covered by the cover member23.

As described above, the clog indicating device20has a simple construction with the indicating float21and cover member23located at the exhaust port19of the dust collector, and is capable of indicating clogging of dust collecting filters in an easily viewable fashion by emergence of the indicating float21, at low cost.

Moreover, since the support shaft22is provided to penetrate the center of the columnar indicating float21vertically such that the float21can slide up and down along the support shaft22, the indicating float21is movable in a steady fashion according to the degree of clogging of filters. Further, since the device of the invention does not require any sensors or detecting circuit, it can be manufactured inexpensively, does not require maintenance and inspection, and rarely goes out of order. Furthermore, since the indicating float21is fabricated of foamed synthetic resin or of a hollow synthetic resin body and thus is very light, it will make the pressure loss in the exhausted air from the dust collector minimum, and will have as less adverse effect as possible on the pressure loss in the exhausted air.