JPS63199978A - Mass flow controller - Google Patents

Abstract

PURPOSE:To miniaturize a device as well as to make highly accurate flow control attainable, by installing a valve body to be controlled for its opening and closing by a sensor part and a piezostack, between an inlet and an outlet of fluid. CONSTITUTION:In an interval between the fluid inlet 3 and the fluid outlet 4 formed in a substrate 1, there are provided with a sensor part 11 and a valve body 21 being controlled for its opening and closing by a valve body driving part 31 consisting of a piezostack. With this constitution, since this valve body driving part 31 is miniaturizable, a mass flow controller can be made yet smaller in size as a whole. In addition, time for occurrence of a strain of the piezostack is very short so that responsiveness is improved and, what is more, opening of the valve body 21 is accurately adjustable, thus flow control ranging from minute flow to large flow can be done at high speed and high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a new and useful mass flow controller.

[Conventional technology]

Conventionally, in mass flow controllers, as shown in Japanese Patent Publication No. 59-28794, for example, a thermal expansion member is thermally expanded, and the displacement of the thermal expansion member at that time is used to drive a valve body to open and close. There is something I did.

[Problem that the invention seeks to solve]

However, according to this prior art, it takes a certain amount of time for the thermal expansion member to thermally expand by a predetermined amount, so the responsiveness is not so good and the control accuracy for opening and closing the valve body is not high. Further, the driving force to the valve body is not very large, and if it is attempted to increase it, the thermal expansion member becomes large and the mass flow controller itself becomes large.

The present invention has been made with the above-mentioned considerations in mind, and its purpose is to provide a mass flow controller that is compact but capable of high-speed and highly accurate flow control from minute flow rates to large flow rates. It is about providing.

[Means for solving problems]

In order to achieve the above object, the fluid control device of the present invention includes a sensor section in which a measuring element for measuring fluid flow rate and a bypass section are connected in parallel between a fluid inlet and a fluid outlet formed in a base body. , and a valve body for controlling the fluid flow rate;
The opening and closing of the valve body is controlled by the strain force of the piezo stack.

[Effect]

According to the above configuration, since the valve body is pressed and driven by the strain force of the piezo stack, the valve body driving portion can be downsized, and therefore the entire mass flow controller can be made smaller.

Since the time required for strain to occur in the piezo stack is extremely short, the response speed is improved, and the opening degree of the valve body can be set with high accuracy. Furthermore, since the distortion of the piezo stack occurs instantaneously and is large, the pressurizing force on the valve body is large, making it possible to perform high-speed and highly accurate flow control from minute flow rates to large flow rates, achieving the above objectives. can do.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a mass flow controller as a so-called normally open type fluid control device, and 1 is a base body. 2 is a valve seat block provided between a fluid port 3 formed in the base body 1 and a fluid outlet 4; 5 is a valve seat; and 5a is a valve port. A flow passage 7 is provided in the base portion 6 of the valve seat block-2.
8 have been established. Reference numerals 9.10 and 10 designate a fluid introduction joint and a fluid discharge joint that are detachably provided at the fluid outlet 3 and the fluid outlet 4, respectively.

11 is a sensor section provided on the upstream side of the valve seat 5, and when the fluid that has passed through the measurement channel population 12 passes through the measurement element 13,
The flow rate is configured to be measured. 14 is the measurement channel outlet, 15.16 is the fixing nut, 17.18.1
9 is a sealing material such as an O-ring. 20 is a bypass section.

21 is a valve body that adjusts the opening degree of the valve port 5a, and its body 22
It is held by a highly elastic bellows 24 so that it can move vertically within the valve block 23, and also so as to form a slight gap G between it and the valve seat 5 under normal conditions. 25, 26, 27, and 28 are sealing materials such as O-rings.

Reference numeral 29 is a cylindrical cover that is erected on the base 1 and is screwed to the valve block 23. 30 is a fixing member. A valve body driving section 31 made of a piezo stack is provided inside and above the cover unit 29. This valve body drive section 31 is
For example, as disclosed in Japanese Patent Application No. 59-249860, a diameter of 10 w1 to 50 m, plated on both the upper and lower sides,
Thickness 0-1m to 0.5m (7) Piezoelectric element, excellent conductivity diameter 10fl to 5Qmm, thickness 0.051 to 0.2
m thin metal plates are alternately laminated one by one (the number of laminated piezoelectric elements is, for example, 100 to 200), each of the metal thin plates is connected every other by a positive electrode lead wire and a negative electrode lead wire, and each lead It is constructed by connecting a lead wire for voltage application to the wire.

For example, a DC5
When a voltage of 00V is applied, each piezoelectric element undergoes a strain of about 60J111 to 100n in the stacking direction, thereby displacing its output portion 32 downward.

33 is a driving force transmission member interposed between the valve body 21 and the valve body drive section 31. This driving force transmission member 33
As shown in the figure, the tongue pieces 35.3 are formed by bending the upper part of the cylindrical body part 34 inward and are independent from each other.
5. 36.36 is a bent part. , 37.
37 is a protrusion formed on the upper surface of the tongue portion 35.35 close to the bent portion 36.36 side. 38.38 is the tongue part ゛35
．． This is the free end of No. 35. The driving force transmitting member 33 is placed so that the lower end of the body 34 is in contact with the seat 23a of the valve block 23.

Thus, the output section 32 of the valve body drive section 31 is connected to the protrusion 37.37.
When the downward pressing blade is applied, the tongue portion 3535
acts as a lever with the bent portion 36.36 as a fulcrum, and therefore the free ends 3B, 38 of the tongue portion 35.35 are amplified by the leverage and are displaced downward (see FIG. 3).

Materials for the driving force transmission member 33 include highly elastic stainless steel, spring steel, plastic, and the like. The bent portions 36 and 36 are provided with sufficient elasticity, and the tongue portions 3
5.35 is preferably formed slightly thick so as not to easily bend.

Note that the shape of the driving force transmitting member 33 is not limited to that shown in FIG. 2; for example, as shown in FIG.・・・
* may be provided radially, or, although not shown, the number of tongue pieces 35 may be one. The body part 34 does not necessarily have to be cylindrical, and may have a bipedal or 311i1 shape as long as it can withstand the pressing force of the valve body drive part 31 and does not deform. Furthermore, the body portion 34 is made shorter than that shown in FIGS. 2 and 4, and this is made shorter than that shown in FIGS.
It may be held by a member other than 3a.

Furthermore, the protrusion 37.37 may be provided on the lower surface of the output section 32 of the valve body drive section 31, as shown in FIG. 5, instead of on the upper surface of the tongue section 35.35. In other words, it is only necessary that the valve body drive section 31 and the driving force transmission member 33 be in point contact or line contact via the projections 37, 37, and the tongue portion 35 may act as a lever.

In the mass flow controller configured as described above, the ratio of the length between the bent portion 36 and the protrusion 37 and the length between the bent portion 36 and the free end portion 38 was set to 1=5. When the tongue piece portion 35... is used, the output portion 3 of the valve body drive portion 31
The displacement amount of No. 2 is amplified five times and transmitted to the valve body 21.

In other words, even if the output part 32 is slightly displaced, the amount of displacement of the valve body 21 becomes large. Therefore, the opening degree of the gap G in the valve port 5a can be adjusted over a wide range, and a large volume of fluid can be controlled. becomes possible.

Incidentally, it goes without saying that the ratio can be set to a desired value as appropriate.

FIG. 6 shows an example in which the present invention is applied to a so-called normally closed type mass flow controller. The only difference from that shown in FIG. 1 is that there are no changes in other structural members. Even with this configuration, the opening degree of the gap G in the valve port 5a can be adjusted over a wide range, and a large volume of fluid can be controlled.

〔Effect of the invention〕

As explained above, the mass flow controller according to the present invention includes a sensor section in which a measuring element for measuring fluid flow rate and a bypass section are connected in parallel between a fluid inlet and a fluid outlet formed in a base body; Since a valve body for controlling the fluid flow rate is provided, and the opening and closing of the valve body is controlled by the strain force of the piezo stack, the valve body driving part can be downsized, and the entire mass flow controller can be made smaller. It can be made smaller. Since the time required for strain to occur in the piezo stack is extremely short, the response speed is improved, and the opening degree of the valve body can be adjusted with high precision. Furthermore, the distortion of the Vinisys tank occurs instantaneously, and because it is large, the pressurizing force on the valve body is large, making it possible to perform high-speed and high-precision flow control from minute flow rates to large flow rates, making it an excellent mass flow controller. You can do the whole thing.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention; FIG. 1 is a vertical cross-sectional view of a normally open type mass flow controller, FIG. 2 is a perspective view of the driving force transmission member, FIG. 3 is a side view of the vicinity of the tongue piece, and FIG. Figure 4 is a perspective view showing another configuration example of the driving force transmitting member, Figure 5 is a side view showing an embodiment in which the protrusion is provided on the valve body driving part side, and Figure 6 is a diagram of a normally closed type mass flow controller. FIG. 3 is a vertical cross-sectional view showing main parts. 1...Base body, 3...Fluid inlet, 4...Fluid outlet,
11...Sensor part, 13...Measuring element, 20...
Bypass section, 21... Valve body, 31... Valve body drive unit. Applicant Estenc Co., Ltd. Agent
Patent Attorney Hideo Fujimoto Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] A sensor section formed by connecting a measuring element for measuring the fluid flow rate and a bypass section in parallel, and a valve body for controlling the fluid flow rate are provided between the fluid inlet and the fluid outlet formed on the base body, A mass flow controller characterized in that a valve body is controlled to open and close by the strain force of a piezo stack.