Orifice member, and differential-pressure flow meter and flow-regulating apparatus using the same

Provided are an orifice member, and a differential-pressure flow meter and a flow-regulating device using the orifice member, that allow purging to be carried out easily when changing the fluid to be circulated, that are less likely to cause contamination and leaching of impurities to the circulated fluid, and that can be easily produced. The flow-regulating device includes a first pressure-measuring device (object to be connected to) that is connected to one end of the orifice member, and a second pressure-measuring device (object to be connected to) that is connected to the other end of the orifice member, and a flow-regulating valve that is connected to the downstream side of the differential-pressure flow meter, which includes the above-mentioned units. In the orifice member, a tube portion, one end of which is connected to the first pressure-measuring device and other end of which is connected to the second pressure-measuring device and whose internal part forms a channel connecting the first and second pressure-measuring devices, and an orifice provided inside the tube portion are integrated.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a National Phase Application based upon and claiming the benefit of priority to PCT/JP2006/310641, filed on May 29, 2006, which is based upon and claims the benefit of priority to Japanese Patent Application No. 2005-163691, filed Jun. 3, 2005, the contents of both of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to an external orifice member used for a fluid transportation channel in, for example, fluid transportation piping used in various industrial fields, including chemical plants, semiconductor production, food production, and biotechnology, and relates to a differential-pressure flow meter and flow-regulating apparatus using the same.

BACKGROUND ART

An orifice member is used as a component of, for example, a differential-pressure flow meter or a flow-regulating device installed in a fluid transportation channel. A known example of such an orifice member is an orifice device described below in Patent Document 1.

This orifice device is formed by inserting an orifice inside a tube that has joints at both ends. The space between the tube and the orifice is sealed with, for example, an O-ring.

DISCLOSURE OF INVENTION

However, in this orifice device, since the tube and the orifice are provided as separate members, a joint is formed between the tube and the orifice. This joint may cause accumulation of fluid. Thus, to handle fluid such as extremely pure fluid, such as chemicals used in semiconductor production, sufficient purging is required when changing the fluid being circulated so that contamination of the newly circulated fluid does not occur.

Moreover, the tube and the orifice can be made of materials that are less likely to cause contamination and leaching of impurities. However, the O-ring used to seal the tube and the orifice is limited to materials that maintain the sealing performance.

Therefore, there is a possibility of impurities from the O-ring leaching into the fluid circulated through the orifice device. Depending on the properties of the circulated fluid and the degree of purity required for the fluid, in some cases, this orifice member cannot be used.

Furthermore, in this orifice device, since the tube and the orifice are separate members, assembly of the orifice device becomes complicated.

The present invention has been conceived in light of the problems described above. Accordingly, it is an object of the present invention to provide an orifice member, as well as a differential-pressure flow meter and a flow-regulating device using the orifice member, wherein a purging operation carried out when changing the circulated fluid is simplified, contamination and leaching of impurities into the circulated fluid is less likely to occur, and manufacturing is easy.

To solve the above-described problems, the present invention provides the following solutions.

A first aspect of the present invention provides an orifice member including a tube portion whose ends are each connected to an object and whose inner section forms a channel connecting the objects; and an orifice provided inside the tube portion, wherein the tube portion and the orifice are integrated.

The orifice member having such a structure is used as an orifice by connecting both ends of the tube portion to objects such as pipelines or various devices. The connection structure between the tube portion and the objects may be a standard connection structure.

With this orifice member, the tube portion and the orifice are integrated (in other words, the tube portion and the orifice are provided as single member), and there is no joint, which may cause accumulation of fluid, between the tube portion and the orifice.

Therefore, in the orifice member, when the fluid circulated through the channel is changed, the remaining fluid in the channel is reliably pushed out by the fluid newly supplied to the channel, and the fluid in the channel can be quickly changed.

Furthermore, in the orifice member, since the tube portion and the orifice are integrated, only a small number of components is required, production is easy, and a member, such as an O-ring, that may cause contamination of the channel does not have to be provided.

Such an orifice member can be manufactured by injection molding using a mold or by machining (cutting etc.).

In this orifice member, on at least one of the ends of the tube portion, a nut through which the end of the tube portion is passed and a sleeve inserted into the end of the tube portion and forming a large-diameter portion by widening the section near the end of the tube portion outwards in the radial direction may be provided, and, on the inner circumferential surface of the nut, a female threaded portion and an engagement protrusion may provided, the engagement protrusion engaging with the large-diameter portion and protruding from the center area in the longitudinal direction of the tube portion, farther inward in the radial direction than the female threaded portion.

In the orifice member having such a structure, the end of the orifice which is passed through the nut (hereinafter, referred to as the “connection end”) is connected to the object to be connected to, which has a male threaded portion formed on the outer circumferential surface of the connection end for connecting to the tube portion.

The connection end of the tube portion is inserted into the nut whose inner circumferential surface includes the engagement protrusion. Then, the sleeve is inserted into the connection end to form, near the end, the large-diameter portion that engages with the engagement protrusion.

In the orifice member, by engaging the nut through which the tube portion is passed with the male threaded portion of the connection end of the object and tightening the nut while the connection end of the tube portion is facing the connection end of the object, the connection end of the tube portion moves relatively close to the connection end of the object. When the nut is sufficiently tightened, the connection end of the tube portion and the connection end of the object are fixed in an airtight, liquid-tight manner.

By loosening the nut, the connection end of the tube portion and the connection end of the object are freed.

In other words, in this orifice member, connection and disconnection with the object can be easily carried out by moving the nut.

In this orifice member, the sleeve may be an engagement portion that is shaped to engage with the connection end of the object.

In such a case, the connection end of the tube portion and the connection end of the object can be satisfactorily connected.

The orifice member according to the present invention, instead of having a structure as described above in which the sleeve is inserted into the connection end of the tube portion, for example, may have a structure in which, on at least one of the ends of the tube portion, a nut through which the end of the tube portion is passed is provided; the end of the tube portion passing through the nut comprises a large-diameter portion having flexibility, having a diameter larger than other sections, and internally receiving a connection end of the object; and on the inner circumferential surface of the nut, a female threaded portion and an engagement protrusion are provided, the engagement protrusion engaging with the large-diameter portion and protruding from the center area in the longitudinal direction of the tube portion, farther inward in the radial direction than the female threaded portion.

The orifice member having such a structure is connected to the object whose tube-portion-connecting end forms an insertion portion that is inserted into the connection end of the tube portion and whose outer circumferential surface near the tube-portion-connecting end is provided with a male threaded portion.

At least one of the ends of the tube portion is flexible and is inserted into the nut having the engagement protrusion on inner circumferential surface. The section near the end inserted into the nut of the tube portion has diameter larger than other sections. This large-diameter portion engages with the engagement protrusion formed on the inner circumferential surface of the nut by internally receiving the insertion portion of the object and by its deformation being restricted.

Therefore, by engaging the nut through which the tube portion is passed with the male threaded portion of the connection end of the object and tightening the nut while the connection end of the tube portion is facing the connection end of the object and the insertion portion of the object is inserted into the large-diameter portion of the tube portion, the connection end of the tube portion moves, together with the nut, relatively close to the connection end of the object. When the nut is sufficiently tightened, the connection end of the tube portion and the connection end of the object are fixed in an airtight, liquid-tight manner.

By loosening the nut, the connection end of the tube portion and the connection end of the object are freed.

In other words, in this orifice member, connection and disconnection of the object can be easily carried out by moving the nut.

The orifice member according to the present invention, instead of having a structure as described above in which the sleeve or the connection end of the object is inserted into the connection end of the tube portion, for example, may have a structure in which, on at least one of the ends of the tube portion, a nut through which the end of the tube portion is passed is provided; the end of the tube portion passing through the nut is rigid and a large-diameter portion is provided on the outer circumferential surface; and on the inner circumferential surface of the nut, a female threaded portion and an engagement protrusion are provided, the engagement protrusion engaging with the large-diameter portion and protruding from the center area in the longitudinal direction of the tube portion, farther inward in the radial direction than the female threaded portion.

The connection end of the tube portion of the orifice member having such a structure is connected to the object whose outer circumferential surface at the tube-portion-connecting end is provided with a male threaded portion.

The connection end of the tube portion is inserted into the nut having the engagement protrusion on the inner circumferential surface, the section near the connection end inserted into the nut is rigid, and the large-diameter portion is formed on the outer circumferential surface of the section near the connection end.

Therefore, by engaging the nut through which the tube portion is passed with the male threaded portion of the connection end of the object and tightening the nut while the connection end of the tube portion is facing the connection end of the object, the connection end of the tube portion moves, together with the nut, relatively close to the connection end of the object. Then, when the nut is sufficiently tightened, the connection end of the tube portion and the connection end of the object are fixed in an airtight, liquid-tight manner.

By loosening the nut, the connection end of the tube portion and the connection end of the object are freed.

In other words, in this orifice member, connection and disconnection of the object can be easily carried out by moving the nut.

With this orifice member, it is preferable to form at least one of the large-diameter portion of the tube portion and the engagement protrusion of the nut in a shape that allows the nut to easily pass over the large-diameter portion when the end of the tube portion is inserted into the nut and that reliably transmits the tightening force of the nut to the large-diameter portion.

For example, when the large-diameter portion of the tube portion satisfies the above-described condition, it is preferable that the large-diameter portion be formed in a shape such that the diameter at the connection end gradually decreases toward the connection end, and the center area in the longitudinal direction of the tube portion has a surface substantially orthogonal to the axis.

When the engagement protrusion of the nut satisfies the above-described conditions, it is preferable that the engagement protrusion be formed in a shape such that the side having the female threaded portion in the axial direction of the nut has a surface substantially orthogonal to the axis, and the diameter of the side opposite to the female threaded portion in the axial direction of the nut gradually decreases away from the female threaded portion in the axial direction.

The orifice member according to the present invention, instead of having a structure as described above in which the nut is provided on the tube portion, for example, may have a structure in which at least one of the ends of the tube portion is rigid and comprises an engagement portion engaging the tube portion with a tube-portion-connecting end of the object, and a male threaded portion is provided on the outer circumferential surface of the engagement portion.

The engagement portion of the tube portion of the orifice member having such a structure is connected to the tube-portion-connecting end of the object having a connection structure that is the same as the connection structure of the above-described orifice member connecting with the object (when the connection end of the object is a flexible large-diameter portion, the end of the engagement portion of the tube portion has an insertion portion that is inserted into the large-diameter portion of the object).

In other words, in this orifice member, by engaging the nut through which the tube portion is passed with the male threaded portion of the connection end of the object and tightening the nut while the connection end of the tube portion is facing the connection end of the object, the connection end of the tube portion moves, together with the nut, relatively close to connection end of the object. Then, when the nut is sufficiently tightened, the connection end of the tube portion and the connection end of the object are fixed in an airtight, liquid-tight manner.

By loosening the nut, the connection end of the tube portion and the connection end of the object are freed.

In other words, in this orifice member, connection and disconnection with the object can be easily carried out by moving the nut.

In the above-described orifice member whose connection end of the tube portion is rigid, the end of the tube portion forms an engagement portion having a shape for engaging with the tube-portion-connecting end of the object.

In such a case, the connection end of the tube portion and the connection end of the object can be satisfactorily connected.

A second aspect of the present invention provides a differential-pressure flow meter including the orifice member according to the present invention, a first pressure-measuring device being connected to one end of the tube portion of the orifice member, and a second pressure-measuring device being connected to the other end of the tube portion of the orifice member.

In the differential-pressure flow meter having such a structure, an orifice member that does not have a joint, which may cause accumulation of fluid, is used between the tube portion and the orifice. Therefore, when the fluid circulated through the channel is changed, the remaining fluid in the channel is reliably pushed out by the fluid newly supplied to the channel, and the fluid in the channel can be quickly changed.

Furthermore, in the orifice member, since the tube portion and the orifice are integrated, only a small number of components is required, production is easy, and a member, such as an O-ring, that may cause contamination of the channel does not have to be provided.

A third aspect of the present invention provides a flow-regulating device including a differential-pressure flow meter using the orifice member according to the present invention, and a flow-regulating valve connected to the upstream or downstream side of the differential-pressure flow meter.

In the flow-regulating device having such a structure, an orifice member of the differential-pressure flow meter does not have a joint, which may cause accumulation of fluid, between the tube portion and the orifice. Therefore, when the fluid circulated through the channel is changed, the remaining fluid in the channel is reliably pushed out by the fluid newly supplied to the channel, and the fluid in the channel can be quickly changed.

Furthermore, in the orifice member, since the tube portion and the orifice are integrated, only a small number of components is required, production is easy, and a member, such as an O-ring, that may cause contamination of the channel does not have to be provided.

With the orifice member, as well as the differential-pressure flow meter and the flow-regulating device using the orifice member, according to the present invention, purging can be carried out easily and reliably when changing the fluid to be circulated, production is easy because the number of components is small, and contamination of the circulated fluid is less likely to occur because members, such as O-rings, that may cause contamination do not have to be disposed inside the channel.

BEST MODE FOR CARRYING OUT THE INVENTION

First Embodiment

A first embodiment of a flow-regulating device according to the present invention will be described below with reference to the drawings.

As shown inFIG. 1, a flow-regulating device10according to this embodiment is provided in a fluid transportation pipe W used in various industrial fields, including chemical plants, semiconductor production, food production, and biotechnology, and is used to regulate the flow of fluid supplied by back-pressure from the upstream side to the downstream side through the fluid transportation pipe W.

According to this embodiment, the flow-regulating device10is used for a fluid transportation pipe that transports fluid at a back-pressure of about 50 k to 500 k [Pa] by applying pressure, by pumping with a fluid-transporting pump, or by means for applying potential energy.

The flow-regulating device10includes an orifice member11, a first pressure-measuring device12that is connected to the upstream side of the orifice member11to measure the fluid pressure at this position, a second pressure-measuring device13that is connected to the downstream side of the orifice member11to measure the fluid pressure at this position, and a flow-regulating valve14that is connected to the upstream side of the first pressure-measuring device12or the downstream side of the second pressure-measuring device13to control the flow volume of the fluid supplied from upstream to downstream.

The orifice member11, the first pressure-measuring device12, and the second pressure-measuring device13, together with a control device17described below, form a differential-pressure flow meter15for measuring the flow rate of fluid passing through the flow-regulating device10.

Here, for the differential-pressure flow meter, if P1 represents in fluid pressure upstream of the orifice, P2 represents the fluid pressure downstream of the orifice, and Q represents the flow rate of the fluid supplied to the orifice, the following Equation (1) holds:
Q=k√(P1−P2)  (1)
The proportionality coefficient k in Equation (1) is a constant depending on the shape or hole-diameter of the orifice and is determined by actual measurements.

According to this embodiment, the flow-regulating valve14is connected to the downstream side of the second pressure-measuring device13. In this way, sufficiently great back-pressure can be applied to the first and second pressure-measuring devices12and13to stabilize the properties of the first and second pressure-measuring devices12and13, and the measurement accuracy of the first and second pressure-measuring devices12and13is less likely to be affected even when there is a pressure change in the fluid supplied to the flow-regulating device10.

Moreover, according to this embodiment, a pressure-regulating valve16for suppressing pressure change of the fluid supplied to the first pressure-measuring device12so as to maintain a predetermined pressure is provided on the upstream side of the first pressure-measuring device12.

In this way, the measurement accuracy of the first and second pressure-measuring devices12and13is less likely to be affected even when there is a pressure change in the fluid supplied to the flow-regulating device10due to disturbance caused by, for example, other pipe systems connected in parallel with the fluid transportation pipe W whose flow rate is to be regulated.

Here, the pressure-regulating valve16may be configured such that pressure regulation is carried out by manual operation conducted by an operator. In such a case, to facilitate the regulation of the pressure-regulating valve16by the operator, it is preferable to provide, on the first pressure-measuring device12, a display device that allows visual confirmation of a measurement value (i.e., pressure of the fluid sent out from the pressure-regulating valve16). The display device may be an analog meter that displays a measurement value by the position of a needle or a digital meter that displays the measurement value as a numeric value.

The pressure-regulating valve16may be an automatic valve, such as an air-operated valve using pneumatic pressure (electropneumatic regulator). When an air-operated valve is used as the pressure-regulating valve16, it is not only possible to regulate the pressure of the fluid supplied to the first pressure-measuring device12but it is also possible to regulate the flow rate.

The flow-regulating valve14is configured with, for example, a throttle mechanism having a needle-valve structure and a throttle-adjusting device for adjusting the needle position of the throttle mechanism. The throttle-adjusting device includes, for example, a motor and a conversion mechanism (for example, a screw-nut system) for converting the rotation of the rotary shaft of the motor into displacement of a needle.

According to this embodiment, in the flow-regulating valve14, a stepping motor whose rotary shaft rotation can be controlled in a highly accurate manner is used as the motor for the throttle-adjusting device. In this way, the needle position can be controlled in a highly accurate manner (i.e., the amount of throttle of the throttle mechanism can be controlled in a highly accurate manner).

The operation of this stepping motor is controlled by the control device17. More specifically, the stepping motor rotates its rotary shaft by an angle proportional to the number of pulses in a drive signal sent from the control device17.

The control device17controls the degree of opening of the flow-regulating valve14such that the difference between the measurement values or output voltages of the first pressure-measuring device12and the second pressure-measuring device13become a predetermined value set in advance. More specifically, when the difference of the output values or the difference of the output voltages of the pressure-measuring devices are lower than a target value set in advance, the degree of opening of the flow-regulating valve14is increased to increase the flow rate, whereas, when the difference of the output values or the difference of the output voltages of the pressure-measuring devices are higher than the target value, the degree of opening of the flow-regulating valve14is decreased to decrease the flow rate.

According to this embodiment, the control device17controls the flow-regulating valve14by using a PID control method, which has excellent control accuracy and response.

Here, the control device17may determine the flow rate of the fluid passing through the flow-regulating device10on the basis of the difference of the measurement values or output voltages of the first pressure-measuring device12and the second pressure-measuring device13and may control the degree of opening of the flow-regulating valve14such that the difference is eliminated.

As shown inFIG. 2, in the orifice member11, a tube portion21, one end of which is connected to the first pressure-measuring device12and other end of which is connected to the second pressure-measuring device13and whose internal part forms a channel connecting the first and second pressure-measuring devices12and13, and an orifice22provided inside the tube portion21are integrated.

The orifice member11is formed of a material that is less likely to cause contamination of the fluid circulated through the inner channel and less likely to be affected by the fluid, for example, PFA (a copolymer of tetrafluoroethylene and perfluoroalkoxy vinyl ether).

In this embodiment, the orifice member11has a substantially cylindrical shape in which only a center portion21aalong the longitudinal direction of the tube portion21is solid. The center portion21ain the longitudinal direction has a narrow hole21bthat connects one end to another end in the longitudinal direction and that is formed concentrically with the axis of the tube portion21. This center portion21ain the longitudinal direction forms the orifice22.

In other words, in the orifice member11, the tube portion21and the orifice22are integrated, and there is no joint between the tube portion21and orifice22, which may cause accumulation of fluid.

Therefore, in the orifice member11, when the fluid circulated through the channel is changed, the remaining fluid in the channel is reliably pushed out by the fluid newly supplied to the channel, and the fluid in the channel can be quickly changed.

Furthermore, in the orifice member11, since the tube portion21and the orifice22are integrated, only a small number of components is required, production is easy, and a member, such as an O-ring, that may cause contamination of the channel does not have to be provided.

Such an orifice member11can be manufactured by injection molding using a mold or by machining (cutting etc.).

The inner surface of the tube portion21and the inner surface of the narrow hole21bare connected by a tapered surface21cwhose diameter decreases from an edge, in the longitudinal direction, of the tube portion21toward the center in the longitudinal direction. In other words, an inclined surface following the flow of the fluid in the tube portion21is provided between the inner surface of the tube portion21and the inner surface of the narrow hole21b, and thus the fluid that reaches the center portion21ain the longitudinal direction in the tube portion21is smoothly guided to the narrow hole21b, and the fluid that passes through the narrow hole21bis smoothly pushed downstream. Consequently, fluid is less likely to accumulate at the boundary of the orifice22and the tube portion21.

At each end of the tube portion21, a nut26for inserting the end of the tube portion21and a sleeve27that is inserted into the end of the tube portion21and that forms a large-diameter portion21dat the end of the tube portion21by widening the section near the end of the tube portion21outwards in the radial direction are provided.

On the nut26, a female threaded portion26ais provided on the inner circumferential surface, and an engagement protrusion26bthat protrudes inward in the radial direction of the nut26and engages with the large-diameter portion21dis provided closer to the center portion21ain the longitudinal direction of the tube portion21than the female threaded portion26a. According to this embodiment, the engagement protrusion26bis an internal flange that is formed around the entire circumference of the nut26.

The sleeve27is a substantially cylindrical member whose internal section forms the channel and is inserted into the tube portion21with one end thereof protruding from the end of the tube portion21.

In the sleeve27, the end protruding from the end of the tube portion21(hereinafter this end is referred to as the “protruding end”) is an engagement portion28that is shaped to engage with the connection ends of the first and second pressure-measuring devices12and13. According to this embodiment, the engagement portion28includes a substantially ring-shaped contact surface28athat surrounds the open end of the channel of the sleeve27and that is in surface contact with an end surface of the connection end of the first and second pressure-measuring device12or13and a cylindrical portion28bthat protrudes farther than the contact surface28aand surrounds the contact surface28a.

At the end of the sleeve27inserted in the tube portion21, a large-diameter portion27athat widens the tube portion21outwards in the radial direction is provided.

As shown inFIG. 2, the first pressure-measuring device12includes a housing31that forms a channel whose inner section connects the fluid transportation pipe W and the orifice member11and a main body of the measuring device (not shown) for measuring the fluid pressure in the housing31.

Here, the second pressure-measuring device13has substantially the same structure as the first pressure-measuring device12, except that the flow-regulating valve14is connected instead of the fluid transportation pipe W. Therefore, only the structure of the first pressure-measuring device12will be described, and a detailed description of the second pressure-measuring device13is omitted.

The housing31includes a substantially ring-shaped contact surface31athat is provided on the connection end of the inner channel, connecting to the orifice member11, and that surrounds the open end of the channel to be in surface contact with the contact surface28aof the sleeve27of the orifice member11; a cylindrical portion31bthat protrudes farther than the contact surface31aand surrounds the contact surface31a; and a ring-shaped depressed portion31cthat is interposed between the contact surface31aand the cylindrical portion31band into which the cylindrical portion28bof the orifice member11is inserted.

On the outer circumferential surface of the cylindrical portion31b, a male threaded portion31dthat is screwed into the female threaded portion26aof the nut26of the orifice member11is formed.

Here, a typical connection structure can be used as the connection structure for the housing31and the fluid transportation pipe W (in the case of the second pressure-measuring device13, the connection structure with the flow-regulating valve14).

In the orifice member11of the flow-regulating device10having such a structure, while one end of the tube portion21in the longitudinal direction is facing the connection end of the channel of the first pressure-measuring device12, the nut26through which this end is passed is engaged with the male threaded portion31dprovided on the cylindrical portion31bof the housing31of the first pressure-measuring device12, and the nut26is tightened. In this way, the engagement portion28of the sleeve27protruding from this end moves relatively close to the housing31, together with the nut26. When the nut26is sufficiently tightened, as shown inFIG. 3, the contact surface28aforming the engagement portion28of the sleeve27and the contact surface31aof the housing31are pushed towards each other while being in surface contact, and the cylindrical portion28bforming the engagement portion28of the sleeve27is inserted into the depressed portion31cof the housing31. In this way, the engagement portion28and the housing31are fixed in an airtight, liquid-tight manner.

By loosening the nut26, the fixed engagement portion28and the housing31are freed.

The connection and disconnection operations of the orifice member11and the second pressure-measuring device13are the same as the connection and disconnection operations of the orifice member11and the first pressure-measuring device12.

In other words, in the orifice member11of the flow-regulating device10, connection and disconnection with the pressure-measuring devices can be easily carried out by moving the nut26.

According to this embodiment, the sleeve27is structured to include the engagement portion28. However, the embodiment is not limited thereto, and instead of the sleeve27, a ring-shaped sleeve37that does not include an engagement portion28may be inserted farther than the end of the tube portion21to form a large-diameter portion21din the tube portion21, as shown inFIGS. 4 and 5.

In such a case, the engagement portion28is formed by the end of the tube portion21(however, the cylindrical portion28bis not provided, and the end of the tube portion21functions as the contact surface28a). Moreover, each of the first pressure-measuring device12and the second pressure-measuring device13includes, instead of the housing31, a housing38that has a structure in which the depressed portion31cis eliminated from the housing31.

Second Embodiment

A second embodiment of a flow-regulating device according to the present invention will be described below with reference toFIGS. 6 and 7.

As shown inFIG. 6, a flow-regulating device40according to this embodiment is mainly characterized in that, instead of the orifice member11, the first pressure-measuring device12, and the second pressure-measuring device13of the flow-regulating device10according to the first embodiment, an orifice member41, a first pressure-measuring device42, and a second pressure-measuring device43having connection structures, for connecting to each other, that are different from those in the flow-regulating device10are provided.

Hereinafter, members that are the same or similar to those according to the first embodiment are represented by the same reference numerals, and detailed descriptions thereof are omitted.

As shown inFIG. 7, the orifice member41is mainly characterized in that, instead of the tube portion51and the sleeve27of the orifice member11according to the first embodiment, a tube portion51is provided, being structured such that each end inserted into the nut26is a large-diameter portion46internally receiving a connection end, described below, of the first pressure-measuring device42or the second pressure-measuring device43by being flexible and wider than other parts, and the engagement protrusion26bof the nut26engages with the this large-diameter portion46.

Here, since the end of the tube portion51is flexible and deformable, it can be easily passed through the nut26.

The first pressure-measuring device42is mainly characterized in that the contact surface31aand the depressed portion31cin the first pressure-measuring device12according to the first embodiment are not provided, and an insertion portion42athat is inserted into the large-diameter portion46of the tube portion51is provided at the tip of the cylindrical portion31b.

The second pressure-measuring device43has substantially the same structure as the first pressure-measuring device42, except that the flow-regulating valve14is connected instead of the fluid transportation pipe W; and, thus, detailed descriptions thereof are omitted.

In the flow-regulating device40having the above-described structure, the ends of the tube portion51of the orifice member41face the insertion portions42aof the first pressure-measuring device42and the second pressure-measuring device43, and the insertion portions42aare inserted into the large-diameter portions46of the tube portion51. By internally receiving the insertion portions42a, deformation is restricted so that the large-diameter portions46engage with the engagement protrusion26bprovided on the inner circumferential surface of the nut26.

With the insertion portion42ainserted into the large-diameter portion46, the nut26through which the tube portion51is passed is engaged with a male threaded portions31dformed on the cylindrical portions31bof the first pressure-measuring device42or the second pressure-measuring device43, and the nut26is tightened. In this way, the large-diameter portion46of the tube portion51moves relatively closer to the cylindrical portions31b, together with the nut26. With the nut26sufficiently tightened, the large-diameter portion46of the tube portion51and the insertion portion42aare fixed in an airtight, liquid-tight manner.

In contrast, by loosening the nut26, the end of the tube portion51and the connection end of each pressure-measuring device42,43are freed.

In other words, the orifice member41can be easily connected to or disconnected from each pressure-measuring device42,43by moving the nut26.

Third Embodiment

A third embodiment of a flow-regulating device according to the present invention will be described below with reference toFIGS. 8 and 9.

A flow-regulating device60according to this embodiment is mainly characterized in that, instead of the orifice member11of the flow-regulating device10according to the first embodiment, an orifice member61having different connection structures for the first and second pressure-measuring devices12and13is provided.

Hereinafter, members that are the same or similar to those according to the first embodiment are represented by the same reference numerals, and detailed descriptions thereof are omitted.

The orifice member61is mainly characterized in that, instead of the tube portion21and the sleeves27in the orifice member11according to the first embodiment, a tube portion71is provided, being structured such that each end is inserted into the nut26is rigid and a large-diameter portion66is formed on the outer circumferential surface of the end, and that the engagement protrusion26bof the nut26engages with the large-diameter portion66.

Moreover, similar to the sleeve27according to the first embodiment, at the end of the tube portion71, a contact surface28aand a cylindrical portion28bthat form an engagement portion28are integrated.

Here, in the orifice member61, it is preferable to form at least the large-diameter portion66of the tube portion71or the engagement protrusion26bof the nut26in a shape that allows the nut26to easily pass over the large-diameter portion66when the end of the tube portion71is inserted into the nut26and that reliably transmits the tightening force of the nut26to the large-diameter portion66.

According to this embodiment, the large-diameter portion66of the tube portion71is formed in a shape such that the diameter of the end area of the tube portion71gradually decreases toward the end, and the center area in the longitudinal direction of the tube portion71has a surface substantially orthogonal to the axis.

In the engagement protrusion26bof the nut26, the side of the female threaded portion26ain the axial direction of the nut26has a surface substantially orthogonal to the axis, and the diameter of the side opposite to the female threaded portion26ain the axial direction of the nut26gradually decreases away from the female threaded portion26ain the axial direction.

In the flow-regulating device60having such a structure, the orifice member61is connected to the first and second pressure-measuring devices12and13through the same process as that used for the orifice member11in the flow-regulating device10according to the first embodiment. The connection structures of the orifice member61and the first and second pressure-measuring devices12and13are the same as the connection structures of the orifice member11and the first and second pressure-measuring devices12and13according to the first embodiment.

According to this embodiment, a tube portion71having the cylindrical portions28bprovided at the end as single members has been described. However, the tube portion71is not limited thereto, and, as shown inFIG. 10, a tube portion76not having the cylindrical portions28bmay be used.

In this case, each of the housings31of the first and second pressure-measuring devices12and13is structured without the depressed portion31c, as shown inFIG. 11.

Fourth Embodiment

A fourth embodiment of flow-regulating devices according to the present invention will be described below with reference toFIG. 12.

A flow-regulating device80according to this embodiment is mainly characterized in that, instead of the orifice member11, the first pressure-measuring device12, and the second pressure-measuring device13in the flow-regulating device10according to the first embodiment, an orifice member81, a first pressure-measuring device82, and a second pressure-measuring device83having connection structures, for connecting to each other, that are different from those in the flow-regulating device10are provided.

The orifice member81is mainly characterized in that, the structure of the connection portions connecting to the first and second pressure-measuring devices12and13in the orifice member11according to the first embodiment is changed to the structure of the connection portions of the first and second pressure-measuring devices12and13connecting to the orifice member11.

More specifically, the orifice member81is the same as the orifice member11according to the first embodiment, except that the nut26and the sleeve27are not provided and, instead of the tube portion21, a tube portion91having the structure shown inFIG. 12is provided.

The tube portion91is the same as the tube portion21according to the first embodiment, except that both ends are rigid, and each end includes a substantially ring-shaped contact surface31athat surrounds the open end of the channel, a cylindrical portion31bthat protrudes in the axial direction farther than the contact surface31aand that surrounds the contact surface31a, and a ring-shaped depressed portion31cthat is provided between the contact surface31aand the cylindrical portion31b. Here, on the outer circumferential surface of the cylindrical portion31b, a male threaded portion31dis formed.

The first pressure-measuring device82and the second pressure-measuring device83are the same as the first pressure-measuring device12and the second pressure-measuring device13, respectively, according to the first embodiment, except that, instead of the contact surface31a, the cylindrical portion31b, the depressed portion31c, and the male threaded portion31d, a tube portion96led out from the housing, a nut26though which the end of the tube portion96is passed, and a sleeve27that is inserted into the end of the tube portion96and that forms a large-diameter portion21dat the end of the tube portion96by widening the section near the end of the tube portion96outwards in the radial direction are provided.

Here, similar to the first embodiment, the sleeve27includes an engagement portion28that is formed of a substantially ring-shaped contact surface28athat surrounds the open end of the channel of the sleeve27and is in surface contact with the end surface of a connection end of the first and second pressure-measuring devices12and13, and a cylindrical portion28bthat protrudes father than the contact surface28aand surrounds the contact surface28a.

The orifice member81, the first pressure-measuring device82, and the second pressure-measuring device83of the flow-regulating device80, having the above-described structure, are connected by the same connection method as the connection method of the orifice member11, the first pressure-measuring device12, and the second pressure-measuring device13of the flow-regulating device10according to the first embodiment (but, the male and female connection structures are reversed).

According to this embodiment, as shown inFIG. 13, the orifice member81may include, instead of the tube portion91, a tube portion98having a structure in which the depressed portion31cis eliminated from the tube portion91.

In this case, on each of the first and second pressure-measuring devices82and83, a large-diameter portion21dis formed on the tube portion96by inserting a ring-shaped sleeve37, which does not have the engagement portion28, farther than the end of the tube portion96. The engagement portion28is formed by the end of the tube portion96(but the cylindrical portion28bis not provided and the end of the tube portion96functions as a contact surface28a).

According to this embodiment, the orifice member81may include, instead of the tube portion91, a tube portion99having a structure in which, in the tube portion91, the contact surface31aand the depressed portion31care not provided and an insertion portion42ato be inserted into a large-diameter portion46of the tube portion96is provided at the tip of the cylindrical portion31b.

In this case, in each of the first and second pressure-measuring devices82and83, the sleeve37is not provided, and, instead of the tube portion96, a tube portion100is provided, wherein the tube portion100has the same structure as the tube portion96, except that the end is a large-diameter portion46that has flexibility, has a diameter larger than other portions, and internally accepts, which is described below, of the tube portion91of the orifice member81, and except that the engagement protrusion26bof the nut26is engaged with the large-diameter portion46.

Here, since the end of the tube portion100is flexible and deformable, it can be easily passed through the nut26.

In this embodiment, cases in which the connection structures at the ends of an orifice member are male and female structures have been described. However, the connection structures are not limited thereto, and one end of the orifice member may be a male connection structure and the other end may be a female connection structure.