FLOW RATE MEASUREMENT DEVICE

A flow rate measurement device measures the flow rate of purge gas in a purge device configured to supply the purge gas to a container including a bottom lid configured to be attached to and detached from a container body. The flow rate measurement device includes: a base on which a flow-rate measurer is mounted; an engaged part provided in the base and configured to be engaged with the bottom lid; and a flow passage through which the purge gas injected from an injection port of the bottom lid is circulated to the flow-rate measurer when the engaged part is engaged with the bottom lid.

TECHNICAL FIELD

This disclosure relates to a flow rate measurement device.

BACKGROUND

A flow rate measurement device configured to measure a flow rate of purge gas in a purge device configured to supply the purge gas to a container is known. For example, Japanese Unexamined Patent Publication No. 2008-159734 discloses a technique for measuring the flow rate of purge gas, which additionally uses a flow rate measurement device (FOUP for measurement) having the same shape as that of a container (FOUP for storage).

In the disclosure described above, the flow rate measurement device is manufactured by, for example, preparing a container used for a purge device, cutting and processing the container, and installing a flow-rate measurer and other equipment on the container. Thus, measuring the flow rate of purge gas involves a problem in that much time and labor are required.

It could therefore be helpful to provide a flow rate measurement device that can easily measure the flow rate of purge gas in a purge device.

SUMMARY

A flow rate measurement device is configured to measure a flow rate of purge gas in a purge device configured to supply the purge gas to a container including a bottom lid configured to be attached to and detached from a container body. The flow rate measurement device includes: a base on which a flow-rate measurer is mounted; an engaged part provided in the base and configured to be engaged with the bottom lid; and a flow passage through which the purge gas injected from an injection port of the bottom lid is circulated to the flow-rate measurer when the engaged part is engaged with the bottom lid.

With this flow rate measurement device, when the engaged part is engaged with the bottom lid, the flow rate of purge gas in the purge device can be measured by effectively utilizing an existing function of the injection port, for example, of the bottom lid. Thus, the flow rate of purge gas in the purge device can be easily measured.

The bottom lid may include a latch and be attached to the container body with the latch, and the engaged part may be engaged with the latch. In this example, the engaged part can be engaged with the bottom lid by effectively utilizing the latch of the bottom lid.

The base may include a frame having a frame shape corresponding to an outer shape of the bottom lid and configured to be stacked on the bottom lid to surround an edge of the bottom lid, and the engaged part may be a hole or a groove, formed in the frame, into which the latch is inserted. In this example, the configuration in which the engaged part is engaged with the bottom lid by effectively utilizing the latch can be concretely implemented.

The frame may have a stepped surface configured to be brought into contact with an upper surface of the bottom lid to restrict upward movement of the bottom lid. In this example, the bottom lid can be prevented from moving upward away from the frame, and thus the engaged part can be easily engaged with the bottom lid.

The flow passage may include an inlet pad configured to be brought into intimate contact with a rim of the injection port on the upper surface of the bottom lid when the engaged part is engaged with the bottom lid. In this example, leakage of purge gas can be prevented, and the flow rate of the purge gas can be reliably measured.

The inlet pad may include a first layer provided on a side closer to the injection port and made of elastic material and a second layer stacked on the first layer and made of gel material. In this example, leakage of purge gas can be further prevented.

The base may have a pressing surface disposed opposite to the bottom lid and configured to press the inlet pad, which is in intimate contact with the rim of the injection port, against the bottom lid when the engaged part is engaged with the bottom lid. In this example, leakage of purge gas can be further prevented.

In the base, at least one of a positioning hole into which a positioning projection provided on the bottom lid is inserted and a positioning projection configured to be inserted into a positioning hole provided in the bottom lid may be formed. In this example, the bottom lid can be positioned with respect to the base.

Our flow rate measurement device thus easily measures the flow rate of purge gas in the purge device.

REFERENCE SIGNS LIST

DETAILED DESCRIPTION

An example will now be described with reference to the drawings. In the description of the drawings, like elements are designated by like reference signs, and duplicate description is omitted. The scale in the drawings does not necessarily coincide with the size of a described object.

A flow rate measurement device measures the flow rate of purge gas in a purge device. The purge device is a device configured to purge the inside of a storage container with purge gas, and is disposed in a purge stocker, for example. First, the purge device and the purge stocker will be described.

As illustrated inFIGS.1and2, a purge stocker1purges the inside of a storage container50with purge gas, and also functions as a repository configured to store a plurality of the storage containers50. Each storage container50is a container such as an SMIF pod or a reticle pod in which an object to be stored such as a semiconductor wafer or a glass substrate is stored. As the purge gas, for example, nitrogen gas or air is used. The purge stocker1is provided in a clean room, for example. The purge stocker1mainly includes a partition3, racks7, a crane9, an overhead hoist transfer (OHT) port21, and a manual port23.

The partition3is a plate covering the purge stocker1. Inside the partition3, a storage area for storing the storage containers50are formed. The racks7are sections in which storage containers50are stored, and are provided in one or a plurality of rows (two rows) in the storage area. Each rack7extends in a certain direction x, and two adjacent racks7,7are disposed parallel to each other to be opposed in a direction y. In each rack7, a plurality of purge shelves7A on which the respective storage containers50are placed to be stored are formed along the certain direction x and the vertical direction z. The purge shelves7A are disposed to be aligned in plurality along the vertical direction z, and are also disposed to be aligned in plurality along the certain direction x.

The crane9is a conveying device configured to bring a storage container50onto and out from a purge shelf7A, and also move a storage container50between a purge shelf7A and each of the OHT port21and the manual port23. The crane9is disposed in an area sandwiched between the opposed racks7,7. The crane9moves on a traveling rail (not illustrated) installed on a floor along the certain direction x in which the racks7extend. The crane9includes a guide rail9A extending in the vertical direction z and a platform9B configured to be movable up and down along the guide rail9A. Conveyance of the storage containers50by the crane9is controlled by a crane controller60. The crane controller60is an electronic control unit including a central processing unit (CPU), a read only memory (ROM), and a random access memory (RAM), for example.

The storage containers50are brought into and out from the purge stocker1through the OHT port21and the manual port23. The OHT port21is a section where a storage container50is transferred between an overhead traveling vehicle (OHT)27, which travels on a traveling rail25installed on a ceiling, and the purge stocker1. The OHT port21includes a conveyor21A configured to convey a storage container50. The manual port23is a section where a storage container50is transferred between an operator and the purge stocker1. The manual port23includes a conveyor23A configured to convey a storage container50.

The storage containers50will be specifically described. Each storage container50includes a container body51and a bottom lid53. In the storage container50, the bottom lid53is attached to and detached from the bottom side of the container body51. The container body51has a rectangular box shape. The bottom lid53has a rectangular plate shape. In the storage container50, a sealed space54is formed by the container body51and the bottom lid53. In the sealed space54, a plurality of semiconductor wafers (not illustrated) are stored.

As illustrated inFIGS.2,3, and4, in both left and right rear end portions of the bottom lid53, injection ports52A are provided. In both left and right front end portions of the bottom lid53, discharge ports52B are provide. Each injection port52A is configured to be connectable to a nozzle, which is not illustrated, provided at a distal end of a supply pipe31of the purge device30. Each discharge port52B is configured to be connectable to a nozzle, which is not illustrated, provided at a distal end of a discharge pipe33of the purge device30. In the injection port52A and the discharge port52B, check valves are provided. The “front” and the “rear” correspond to the near side and the far side of each purge shelf7A, respectively, and the “left” and the “right” correspond to one side and the other side of a horizontal direction orthogonal to the front-and-rear direction, respectively.

The bottom lid53is provided with a latch mechanism58, for example. The latch mechanism58includes latches58A and a cam58B. In the latch mechanism58, when a key (not illustrated) is inserted into insertion holes58C formed in a bottom surface53aof the bottom lid53and this key is turned, the latches58A are moved in and out (brought in and out) by the cam58B. The latches58A are provided on the front side and the rear side of the bottom lid53. The latches58A provided on the front side can protrude forward from the front surface of the bottom lid53, and the latches58A provided on the rear side can protrude backward from the rear surface of the bottom lid53.

The latches58A are fitted into fitting grooves51A provided in the container body51. By this fitting, the bottom lid53is fixed to the container body51. In other words, the bottom lid53is attached to the container body51with the latches58A. On two front corners of the four corners of the bottom lid53, positioning projections59are formed upright. The positioning projections59are protrusions for positioning the bottom lid53with respect to the container body51.

The purge device30will be specifically described. As illustrated inFIG.2, the purge device30is a device configured to supply purge gas to the storage container50placed on the purge shelf7A, and includes supply pipes31, a mass flow controller (MFC)35, a purge gas source37, discharge pipes33, a flowmeter39, and a purge controller40.

The supply pipes31are pipes for supplying purge gas, and are connected to the injection ports52A of the bottom lid53. The MFC35is an instrument configured to measure the mass flow rate of purge gas flowing through the supply pipes31to control the flow rate. The purge gas source37is a tank configured to store purge gas. The discharge pipes33are pipes for discharging purge gas, and are connected to the discharge ports52B of the bottom lid53. The flowmeter39is an instrument configured to measure the flow rate of purge gas flowing through the discharge pipes33. The purge controller40controls various purging processes in the purge device30. The purge controller40is an electronic control unit including a CPU, a ROM, and a RAM, for example.

The following describes the flow rate measurement device according to the example.

As illustrated inFIGS.5and6, a flow rate measurement device100is a device detachably attached to the bottom lid53and configured to measure the flow rate of purge gas in the purge device30by using the bottom lid53. The flow rate measurement device100includes a frame110on which two flow-rate measurers101are mounted, long holes120provided in the frame110, and flow passages130connected to the flow-rate measurers101. The terms “upper” and “lower” correspond to the upper and lower directions in a state of being attached to the bottom lid53.

As illustrated inFIGS.5,6, and7, the frame110is a member having a frame shape corresponding to the outer shape of the bottom lid53. The frame110has a rectangular frame shape. The frame110is formed of thermoplastic resin (such as polyacetal (POM)), for example. The frame110includes as its framework members a front ledge110F, a rear ledge110B, and side ledges110L,110R. The front ledge110F and the rear ledge110B are members extending along the left-and-right direction. The side ledges110L,110R are members extending along the front-and-rear direction. The side ledge110L is continuous with the left ends of the front ledge110F and the rear ledge110B, and the side ledge110R is continuous with the right ends of the front ledge110F and the rear ledge110B. The frame110constitutes the base.

The frame110has overhangs112that are provided on the respective inner portions of the two rear corners to overhang inward. The overhangs112have a plate shape. The overhangs112are disposed opposite to the bottom lid53and located above the injection ports52A when the frame110is stacked on the bottom lid53. The upper surfaces of the overhangs112are continuous with an upper surface110bof the frame110. The lower surfaces of the overhangs112are planar surfaces that extend inward with steps interposed therebetween above the stepped surface111and are parallel to the lower surface110a. The lower surfaces of the overhangs112constitutes pressing surfaces112aconfigured to press inlet pads133against the bottom lid53as described later.

The frame110has positioning holes113into which the positioning projections59provided on the bottom lid53are inserted. The positioning holes113are formed in the two front corners of the four corners of the frame110. The positioning holes113are through holes passing through vertically and each having a cross section corresponding to the shape of the positioning projections59.

On the upper surface110bof the frame110, a plate member114is stacked and fixed. The plate member114supports various instruments mounted on the frame110. The plate member114is formed of a material (such as metal) having a stiffness higher than that of the frame110. The plate member114is disposed to extend over the rear ledge110B and the side ledges110L,110R. On the plate member114, two mass flowmeters101, a battery102, a converter103, and a data logger104are fixed.

Each mass flowmeter101is an instrument configured to measure the flow rate of purge gas. The mass flowmeter101is not limited to a particular one, and various flowmeters may be used. The battery102is a storage battery configured to store electric power to be supplied to the mass flowmeters101and the data logger104. The battery102is not limited to a particular one, and various batteries may be used. The converter103transforms the electric power from the battery102to supply the transformed electric power to the mass flowmeter101and the data logger104. The converter103is a DC-DC converter, for example. The converter103is not limited to a particular one, and various converters may be used. The data logger104is a recorder configured to record results of measurements taken by the mass flowmeter101. The data logger104is not limited to a particular one, and various data loggers may be used.

The long holes120are engaged parts formed in the frame110and configured to be engaged with the latches58A (seeFIG.3) inserted thereinto. In other words, the latches58A are fitted into the long holes120when the frame110is stacked on the bottom lid53. The long holes120are formed in the front ledge110F and the rear ledge110B of the frame110. Each long hole120is a hole, the longitudinal direction of which corresponds to the left-and-right direction, penetrating in the front-and-rear direction. The long holes120have a vertical width corresponding to the vertical width of the latches58A. When the frame110is stacked on the bottom lid53, the long holes120are disposed opposite in the front-and-rear direction to the latches58A not protruding from the bottom lid53. The long holes120are provided, the number of which is the same as or more than that of the latches58A.

The flow passages130allow purge gas injected from the injection ports52A of the bottom lid53to circulate therethrough to the flow-rate measurers101in a state in which the frame110is stacked on the bottom lid53and the long holes120are engaged with the latches58A of the bottom lid53(“engaged state of the frame110”). Each flow passage130includes a vent hole131, a tube132, and the corresponding inlet pad133.

The vent hole131is a through hole formed in the corresponding overhang112. The vent hole131communicates with the corresponding injection port52A of the bottom lid53in the engaged state of the frame110. One end of the tube132is connected to the corresponding flow-rate measurer101. The other end of the tube132is connected to the upper end of the vent hole131.

The inlet pad133is brought into intimate contact with the rim of the injection port52A on the upper surface of the bottom lid53in the engaged state of the frame110(seeFIG.10). The inlet pad133is a ring-shaped member. As illustrated inFIG.8, the inlet pad133is provided on the lower surface of the overhang112to surround the vent hole131when viewed from below. The inlet pad133includes: a first layer133xprovided on a side closer to the injection port52A (lower side) and made of elastic material; and a second layer133yprovided on a side closer to the overhang112(upper side) and made of gel material. The first layer133xand the second layer133yare stacked on one another. The first layer133xis formed of polyurethane rubber, for example. The second layer133yis formed of a gel material containing silicone as a main raw material and having high flexibility.

When the flow rate measurement device100configured as described above is attached to the bottom lid53, for example, an operator positions the flow rate measurement device100above the bottom lid53as illustrated inFIG.9. At this time, the front-and-rear orientation of the flow rate measurement device100is aligned such that the positioning holes113are positioned above the positioning projections59. The latches58A are set in a state of not protruding from the bottom lid53.

Subsequently, the operator stacks the frame110on the bottom lid53such that it surrounds the edges of the bottom lid53as illustrated inFIG.10, and connects the vent holes131to the injection ports52A with the inlet pads133interposed therebetween. At this time, the positioning projections59are inserted into the positioning holes113. The inlet pads133are brought into intimate contact with the rims of the injection ports52A, and the inlet pads133are pressed against the bottom lid53by the pressing surfaces112aof the overhangs112, whereby the inlet pads133are deformed to be compressed vertically.

Subsequently, the operator inserts the key into the insertion holes58C (seeFIG.4) of the bottom lid53and turns the key, thereby causing the cam58B to protrude the latches58A from the bottom lid53as illustrated inFIG.11. By this operation, the latches58A are inserted and fitted into the long holes120. Consequently, the frame110is engaged with the bottom lid53, whereby attachment of the flow rate measurement device100to the bottom lid53is completed.

In the same manner as for each storage container50, the flow rate measurement device100attached to the bottom lid53is brought in and out from the purge shelves7A in a predetermined order by the crane9, and when placed on each purge shelf7A, purge gas is supplied thereto by the purge device30. The flow rate measurement device100attached to the bottom lid53measures the flow rate of the purge gas with the mass flowmeters101, and records the measurement results in the data logger104.

When the flow rate measurement device100is then removed from the bottom lid53, the operator inserts the key into the insertion holes58C of the bottom lid53and turns the key, thereby causing the cam58B to retract the latches58A into the bottom lid53and withdrawing the latches58A from the long holes120to release the engagement. The operator then lifts the flow rate measurement device100upward and pulls out the positioning projections59from the positioning holes113to complete the removal.

With the flow rate measurement device100described above, when the long holes120are engaged with the bottom lid53and the flow rate measurement device100is attached to the bottom lid53, the flow rate of purge gas in the purge device30can be measured by effectively utilizing an existing function of the injection ports52A, for example, of the bottom lid53. Thus, the flow rate of purge gas in the purge device30can be easily measured. The flow rate measurement device100can also be attached to another bottom lid different from the bottom lid53, and thus versatility can be increased.

In the flow rate measurement device100, the long holes120are engaged with the latches58A configured to attach the bottom lid53to the container body51. In this example, the long holes120can be engaged with the bottom lid53by effectively utilizing the latches58A of the bottom lid53. The flow rate measurement device100can be easily attached to the bottom lid53.

In the flow rate measurement device100, the frame110has a frame shape corresponding to the outer shape of the bottom lid53and is stacked on the bottom lid53to surround the edges of the bottom lid53. In the frame110, the long holes120into which the latches58A are inserted are formed. In this example, the configuration in which the long holes120are engaged with the bottom lid53by effectively utilizing the latches can be concretely implemented.

In the flow rate measurement device100, the frame110has the stepped surface111configured to be brought into contact with the upper surface of the bottom lid53to restrict the upward movement of the bottom lid53. In this example, the bottom lid53can be prevented from moving upward away from the frame110, and thus the long holes120can be easily engaged with the bottom lid53.

In the flow rate measurement device100, the flow passages130include the inlet pads133configured to be brought into intimate contact with the rims of the injection ports52A on the upper surface of the bottom lid53when the long holes120are engaged with the bottom lid53. In this example, airtightness between each injection port52A and the corresponding vent hole131can be ensured to prevent leakage of purge gas from between the injection port52A and the vent hole131, and thus the flow rate of purge gas can be reliably measured.

In the flow rate measurement device100, each inlet pad133includes the first layer133xmade of elastic material and the second layer133ymade of gel material. In this example, leakage of purge gas from between the injection port52A and the vent hole131can be further prevented, and thus the flow rate of purge gas can be more reliably measured.

In the flow rate measurement device100, the frame110has the pressing surfaces112aconfigured to press the inlet pads133against the bottom lid53when the long holes120are engaged with the bottom lid53. In this example, leakage of purge gas from between the injection port52A and the vent hole131can be further prevented, and thus the flow rate of purge gas can be more reliably measured.

In the flow rate measurement device100, in the frame110, the positioning holes113into which the positioning projections59provided on the bottom lid53are inserted are formed. In this example, the bottom lid53can be positioned with respect to the frame110.

Although the example has been described above, this disclosure is not limited to the above example. In the above example, various modifications can be made within the scope not departing from this disclosure.

In the above example, the positioning projections59are provided on the bottom lid53, and the positioning holes113are formed in the frame110into which they are inserted. However, instead of or in addition to these, positioning holes may be provided in the bottom lid53, and positioning projections configured to be inserted thereinto may be formed on the frame110.

In the above example, the long holes120are formed as engaged parts. However, the engaged parts are not limited to the long holes120. The engaged parts may be holes having other shapes such as round holes, may be grooves, or may be protrusions. In short, the engaged parts only need to have a configuration in which the engaged parts can be engaged with the bottom lid53. In the above example, the engaged parts are engaged with the latches58A of the bottom lid53, but may be engaged with engaging parts other than the latches58A.

In the above example, the frame110is included as the base. However, the base may have another configuration other than the frame110. The shape of the frame110is not limited to a rectangular frame shape, and may be of various frame shapes. In the above example, each inlet pad133does not have to include a plurality of layers, and may be formed of a single material.

The materials and shapes of the respective configurations in the example and the modifications above are not limited to those described above, and various materials and shapes may be used. Each configuration in the example or the modifications above may be optionally applied to each configuration in other examples or modifications. Some of the respective configurations in the example or the modifications above may be omitted as appropriate within the scope not departing from the scope of this disclosure.