JP2775207B2 - Pressure reducing valve adjustment device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure reducing valve adjusting device for automatically adjusting the flow rate and pressure of a pressure reducing valve using an electromagnetic valve.

[0002]

2. Description of the Related Art Conventionally, a flow rate and a pressure are regulated by a mechanical setting type pressure reducing valve, and the pressure reducing valve is applied to, for example, a carrier gas flow rate adjusting system of a gas chromatograph. FIG. 5 shows a schematic configuration of the gas chromatograph. An analyzer main body 40, a sample valve 41, a column 42, a detector 43, a measuring tube 44, a carrier gas such as helium, which forms a thermostat and is maintained at a predetermined temperature. A pressure reducing valve 30 for reducing the CG pressure to a predetermined pressure is provided, and the flow path of the sample valve 41 is switched from a solid line state to a broken line state at the time of measurement, so that the measuring pipe 44 is provided.
The sample gas SG to be measured, which has been collected by the above, is sent into the column 42 by the carrier gas CG. Then, each gas component separated by the column 42 is detected by a detector 43 such as a thermal conductivity detector, and the detection signal is subjected to waveform processing by a controller 45 or recorded on a recording paper to analyze a sample gas. Has become.
On the other hand, during non-measurement, the carrier gas CG is guided to the column 42 and the detector 43 by switching the flow path of the sample valve 41 to the state shown by the solid line.

The pressure reducing valve 30 comprises an inner chamber 31 communicating with the carrier gas supply passage 13 and the carrier gas discharge passage 14, a diaphragm 32 for dividing the inner chamber 31 into two upper and lower chambers, a poppet valve 33, a compression coil. A spring 34 and the like are provided. A compression coil spring 35 for setting the pressure, which urges the diaphragm 32 toward the lower chamber, is provided in the upper chamber of the inner chamber 31.
And a spring receiving member 36 for holding the upper end of the compression coil spring 35. When the spring receiving member 36 is moved up and down by the pressure setting screw 37, the spring pressure of the compression coil spring 35 is adjusted. And sheet phosphorus into the chamber side of the lower side
Grayed poppet valve 33 for opening and closing control (not shown) and the flow hole is disposed opposite to the compression coil spring 34, the second carrier gas CG by turning the pressure adjustment screw 37 manually
The secondary pressure P _O (output pressure) is made equal to the set pressure.

However, in such a pressure reducing valve, when the secondary pressure P _{O of the} carrier gas fluctuates due to primary pressure fluctuations, vibrations, load fluctuations, ambient temperature characteristics, etc. of the carrier gas, the flow rate also increases. Column 4 to change
2, the balance of the bridge circuit in the detector 43 and the state of separation of the gas components is lost, and the base voltage fluctuates. Each time, the set pressure of the pressure reducing valve 30 is changed by turning the pressure setting screw 37. It is very troublesome to go to the apparatus and manually operate the pressure setting screw 37, and there is a problem that pressure fluctuations cannot be quickly dealt with.

In order to solve such a problem, the same applicant has proposed an apparatus for automatically adjusting the pressure and flow rate of a pressure reducing valve by using an electromagnetic valve, and FIG. 4 shows a basic configuration thereof. . As shown in FIG. 4, the apparatus comprises an inner chamber 11, a diaphragm 12 for dividing the inner chamber 11 into two upper and lower chambers 11A and 11B, and a carrier gas supply passage 13 communicating with an inlet and an outlet of the inner chamber 11, respectively. The pressure reducing valve 1 includes a carrier gas discharge flow path 14, a poppet valve 15, a compression coil spring 16, and the like. The lower chamber 11A forms a pressure chamber, and the upper chamber 11B forms a back pressure chamber. . The back pressure chamber 11B, which reduces the pressure of the carrier gas sent from the carrier gas supply channel 13 to a predetermined pressure P ₀ , has one inlet / outlet 21. The branch pressure passage 18 communicates with the back pressure passage 18 through the branch passage 19. Further, a fixed throttle 20 made of a sintered metal or the like is arranged in the branch path 19.

The first and second solenoid valves 2 located on the supply side and the discharge side of the back pressure flow path 18 with a branch path 19 interposed therebetween.
2 and 23, and a pressure sensor 2 for detecting a secondary pressure P _O of the pressure reducing valve 1 is provided downstream of the supply electromagnetic valve 22. Thus, together with the carrier gas CG is fed to the pressure chamber 11A side of the pressure reducing valve 1 via the flow path 13 as the primary pressure P _S, open the supplying solenoid valve 22, the back pressure passage 18 branch passage 19 to the back pressure chamber 11B through the fixed throttle 20 is sent as the back pressure P _N, the back pressure P _N
And it is made to correspond to the sum of the primary-side pressure P _S and the spring pressure of the compression coil spring 16. And the back pressure _PN is the discharge solenoid valve 23
Open and drop.

Reference numeral 9 denotes a controller for driving the pressure reducing valve 1 to control its output pressure to an arbitrary set value. The controller 9 compares a detection value PV from the pressure sensor 1 with a preset value SP. Based on the comparison result, the two solenoid valves 22 and 23 are controlled to open and close so that the secondary pressure P _O always becomes the set pressure. In this case, the primary pressure P of the carrier gas
_S , the back pressure P _N and the secondary pressure P _O are represented by P _S ≧ P _N
> The P _O. That is, when the detection value PV of the pressure sensor 2 is equal to or less than the lower limit of the set value SP, the secondary pressure _Po is lower than the set pressure. At this time, the supply electromagnetic valve 22 is opened by a signal from the controller 9 while the discharge electromagnetic valve 23 is opened.
Is maintained in the fully closed state, and the pressure of the carrier gas supplied to the back pressure chamber 11B is increased. Then, the back pressure _PN increases, the diaphragm 12 is displaced downward against the compression coil spring 16, and the poppet valve 15 is opened.

Accordingly, the pressure of the carrier gas into the pressure chamber 11A increases, and the secondary pressure P _O increases. When the secondary-side pressure P _O is coincident with the increase in set pressure and closing the supplying solenoid valve 22 for the detection value PV is within the range of the set value SP. If the secondary pressure P _O becomes larger than the set pressure due to disturbance or the like and the detected value PV exceeds the upper limit of the set value SP,
Now lower the back pressure P _N to open the discharge electromagnetic valve 23. Then, the diaphragm 12 is displaced upward by that amount, the poppet valve 15 is closed, and the secondary pressure P _O is reduced.
When the secondary pressure P _O is coincident with the set pressure and closes the discharge solenoid valve 23. Thus, the two solenoid valves 22, 2
The apparatus for adjusting the pressure of the pressure reducing valve 1 by using the pressure reducing valve 3 is less affected by primary pressure fluctuations, vibrations, load fluctuations, ambient temperature characteristics of the pressure reducing valve, etc., and can automatically variably set the set pressure of the pressure reducing valve. And the like.

[0009]

By the way, in the case of the pressure reducing valve 1 having a path for discharging the back pressure _PN to the secondary pressure P _O , when the pressure reducing valve is balanced (balanced), its compression coil When the spring pressure of the spring 16 is k, P _N = P _O + k (1) However, since the diaphragm itself actually has a force F due to the deflection of the diaphragm 12, etc., for example, if the poppet valve 15 is pushed by the force of the F of the diaphragm 12, in a balanced state, P _N + F = P _O + k ( 2) Here, if F> k, then P _N <P _O. In other words, when the discharge solenoid valve 23 is turned on (opened) to reduce the pressure, the secondary pressure P _O having a high pressure flows backward, and as a result, there is a problem that the pressure cannot be adjusted.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has been made in order to solve the above-mentioned problems. An object of the present invention is to adjust the pressure and flow rate of a pressure reducing valve by using an electromagnetic valve. It is an object of the present invention to provide a pressure reducing valve adjusting device capable of improving the performance and operability of the pressure reducing valve.

[0011]

In order to achieve the above object, a pressure reducing valve adjusting apparatus according to the present invention comprises an inner chamber and two inner chambers, an upper back pressure chamber and a lower pressure chamber. Die to partition
The diaphragm and the pressure chamber are supplied to the back pressure chamber side.
Partition into two chambers, a chamber and a discharge chamber on the back pressure chamber side
And the gas supply connected to these supply and discharge chambers respectively.
Connected to the supply channel and the gas discharge channel and the diaphragm
And a first spring is inserted into a flow hole formed in the partition wall.
And the communication hole is opened according to the pressure of the back pressure chamber.
A valve body disposed in the supply chamber so as to be closed, and a second spring having a spring pressure larger than the first spring provided in the back pressure chamber so as to press the diaphragm toward the pressure chamber. And a pressure reducing valve composed of a back pressure flow path communicated via a throttle between the gas discharge flow path and the inlet / outlet of the back pressure chamber. And, the restriction of the back pressure flow path and the
A first supply solenoid valve is arranged between the first solenoid valve and the gas discharge passage, and one end is connected to a back pressure passage between the first solenoid valve and the throttle, and the other end is open to the atmosphere. A second discharge solenoid valve is disposed in the flow path, the secondary pressure of the pressure reducing valve is detected by a pressure sensor, and the detected value of the pressure sensor is compared with a preset reference value. Based on the first
By controlling the opening of the second solenoid valve, the secondary pressure of the pressure reducing valve is kept constant.

[0012]

According to the present invention, the pressure reducing valve has a secondary pressure P _O , a pressure of the back pressure chamber P _N , a spring pressure of the first spring k, and a spring pressure of the second spring K. satisfies P _N + K = formula P _O + k (3) when in equilibrium (P _N <P _O). However, it is assumed that the spring pressure K of the second spring is much higher than the spring pressure k of the first spring, and is expressed as K> k here for convenience. Therefore, even if a force due to the deflection of the diaphragm or the like is applied from the back pressure chamber side to the secondary pressure side, when the second discharge solenoid valve is turned ON, the pressure of the back pressure P _N always goes down, so that P _N > P _O
It does not become. As a result, stable control becomes possible.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings. FIG. 1 is a basic configuration diagram of a pressure reducing valve adjusting device for explaining an embodiment of the present invention. In this embodiment, the pressure reducing valve 1 for adjusting the pressure of the carrier gas is provided with a spring pressure of a compression coil spring 16 so as to press the diaphragm 12 into the back pressure chamber 11B at a predetermined pressure against the pivot valve 15 on the pressure chamber 11A side. Spring pressure K greater than k (where K>
k) is provided. Then, the inlet / outlet 21 of the back pressure chamber 11B and the carrier gas discharge channel 1
The first supply solenoid valve 22 is provided in the back pressure passage 18a between
A second discharge solenoid valve 23 is provided in a flow passage 18b having one end connected to the back pressure passage 18a between the supply solenoid valve 22 and the fixed throttle 20 and the other end open to the atmosphere.

Further, a detection value PV of a pressure sensor 2 for detecting a secondary pressure P _O of the pressure reducing valve 1 passes through an A / D converter 3 and a CPU (microcomputer) as a controller.
4 has been entered. The CPU 4 determines whether the detected value PV from the pressure sensor 2 is in the pressure increasing direction or the pressure decreasing direction, and outputs the first and second gate pulses GP _L and GP _H to the drive gate unit 6 according to the direction. At the same time, the reference value SP is output to the carrier gas pressure controller 5.

As shown in FIG. 2, the carrier gas pressure controller 5 has a predetermined upper limit SP _u and a lower limit SP _D which are set in advance with respect to a reference set value SP. The detected value PV is the set value SP sent from the CPU 4
Tolerance when in range of clogging the set point SP and the lower limit value SP _D, the first electromagnetic valve driving signal VL co for increasing carrier gas _pressure, the second solenoid valve drive signal VH _co for carrier gas pressure reduction of was a "L" level (oFF signal), the detected value PV is when in below the lower limit value SP _D of the set point SP is first electromagnetic valve driving signal VL _co only the "H" level (oN signal). Then, the detection value PV is equal to or more than the upper limit SP _{u of the} set value SP, or the set value SP and the upper limit S
Second electromagnetic valve drive signal VH when in the range of P _u
co is set to the “H” level (ON signal) and its VL
_co, the switches 6 of the signal driving the gate portion 6 of the _{VH co
1, 6 2} to enter respectively.

The drive gate unit 6 controls the first and second solenoid valve drive signals VL _CO , VH by the first and second gate pulses GP _L , GP _H corresponding to the carrier gas pressure control output from the CPU 4. _C0 is turned on / off, converted into a signal having a predetermined pulse width, and output to the solenoid valve driving unit 7. As a result, the solenoid valve driving unit 7
The first supply solenoid valve 22 is controlled to open and close by a first solenoid valve drive signal VL having a predetermined pulse width Ta as shown in FIG.
The opening and closing of the second discharge solenoid valve 23 is controlled by the second solenoid valve drive signal VH having the pulse widths Tb and Tc as shown in FIGS. 3B and 3C output from the drive gate unit 6.

That is, when the detected value PV of the pressure sensor 2 is equal to or smaller than the lower limit value SP _D of the set value SP, the supply electromagnetic wave is supplied by the first solenoid valve drive signal VL having the pulse width Ta shown in FIG. Actuate the valve 22. Then, the second electromagnetic valve driving signal V having a pulse width Tb shown in FIG. 3 (b) when the detected value PV of the pressure sensor 2 is above the upper limit SP _U of the set point SP
A second discharge solenoid valve 23 is driven by H, whereafter the detected value PV is the set point SP and the upper limit value SP when in the range of _U the pulse shown in FIG. 3 (c) the width Tc (where Ta> T
By driving the discharge solenoid valve 23 with the second solenoid valve drive signal VH of b> Tc), the secondary pressure P ₀ of the pressure reducing valve 1 is adjusted. In FIG. 1, the same or corresponding parts as those in FIG. 4 are denoted by the same reference numerals.

Next, the operation of the above embodiment will be described.
First when the detected value PV of the pressure sensor 2 in the carrier gas pressure control unit 5 is less than the lower limit value SP _D setting SP, 2
The secondary pressure _Po is lower than the set pressure. In this case, CPU 4 determines that the pressure increasing direction receives the detection value PV from the pressure sensor 2, and outputs the first gate pulse GP _L to drive the gate unit 6. Then, the carrier gas pressure control unit 5 only the first solenoid valve drive signal VL _CO to "H" level (ON signal), the first of the signal VL _CO is inputted to the switch 6 _first driving gate section 6 On / off control is performed by the gate pulse GP _L , and a signal having a pulse width Ta as shown in FIG.

As a result, the solenoid valve driving unit 7 uses the signal VL having the pulse width Ta shown in FIG.
While the discharge solenoid valve 23 is held in the fully closed state, the back pressure _PN of the back pressure chamber 11B of the pressure reducing valve 1 increases, displacing the diaphragm 12 downward against the compression coil spring 16, The poppet valve 15 is opened. Accordingly, the pressure of the carrier gas CG supplied to the pressure chamber 11A increases, and the secondary pressure P _O increases. When the secondary pressure P _O increases and coincides with the set pressure, the detected value PV becomes the lower limit SP of the set value SP.
_To enter _D , the supply solenoid valve 22 is closed.

Meanwhile when the pressure adjustment of the pressure reducing valve 1, as shown in FIG. 2, when the detection value PV of the pressure sensor 2 exceeds the upper limit value SP _U setting SP, CPU 4 is a detected value PV from the pressure sensor 2 In response to this, it is determined that the pressure is decreasing, and a second gate pulse GP _H corresponding to the direction is output to the drive gate unit 6. Then, the carrier gas pressure control unit 5 only the second solenoid valve drive signal VH _CO to "H" level (ON signal),
The signal is on-off controlled by a second gate pulse GP _H is input to the switch 6 ₂ drive the gate unit 6, 3
A signal VL having a pulse width Tb as shown in (b) is input to the discharge solenoid valve 23 through the solenoid valve driving unit 7.

[0021] This allows the discharge electromagnetic valve 23 lowers the back pressure P _N open. Then, the diaphragm 12 is displaced upward by that amount, the poppet valve 15 is closed, and the secondary pressure P
_{Lower O.} As a result, the secondary pressure P ₀ gradually decreases. When the detected value PV falls below the upper limit value SP _U at the time point Q, the CPU 4 inputs the second gate pulse GP _H to the drive gate unit 6 and outputs the control gate unit 6 as shown in FIG. Only the discharge solenoid valve 23 is driven by the signal VH having such a pulse width Tc. As a result, the pressure reducing valve 1 operates in the same manner as described above, and when the secondary pressure P _O matches the set pressure, the detected value PV becomes the lower limit SP _{D of the} set value SP.
And the first and second solenoid valve drive signals VL and VH both become “L” level (OFF signal), and the discharge solenoid valve 2
3 is closed.

As described above, according to the present embodiment, when adjusting the pressure of the pressure reducing valve 2, as shown in FIG. 2, the upper limit SP _U of the set value SP is set to SP + 0.15 kgf / cm ² , and the lower limit thereof is set to SP + 0.15 kgf / cm ^2. When SP _{D is set} to SP−0.20 kgf / cm ² , if the detection value PV of the pressure sensor 2 is equal to or less than the lower limit value SP _D , a pulse having a duty ratio of 90% is used as a signal VL having a wide pulse width Ta. The first electromagnetic valve 22 for increasing the carrier gas pressure is driven. When the detection value PV of the pressure sensor 2 is equal to or more than the upper limit value SP _U (PV> SP
+0.15), the second solenoid valve 23 for decreasing the carrier gas pressure is driven by a pulse having a duty ratio of 50%, for example, as a signal VL having a pulse width Tb.
When V is within the range of the set point SP and the upper limit value SP _U is a (SP ≦ PV ≦ SP + 0.15 ), the second solenoid valve 23 by a signal VL and to for example a duty ratio of 10% of the pulse of narrow pulse width Tc by driving, as shown in FIG. 2, it can be controlled quickly to pressure reducing valve stationary zone the secondary pressure P ₀ within T ₁ predetermined pressure adjustment time of _{2 (SP D ≦ PV <SP} ) within.

Further, according to the present embodiment, when the diaphragm 12 in the back pressure chamber 11B of the pressure reducing valve 1 pushes the poppet valve 15 downward by the force F due to its bending or the like, P _O + k = P _{N in} a balanced state. + K + F (4) At this time, the spring pressure K of the compression coil spring 17 is much larger than the spring pressure k of the compression coil spring 16 (K>
k), P _O <P _N + F. Also, the compression coil spring 17
Since the spring pressure K is large, it is considered that P _O <P _N. However, even if P _O > P _N , if the discharge solenoid valve 23 is turned ON, the pressure P _N of the back pressure chamber 11B is changed to the atmosphere. Since the pressure is released and always drops, the pressure regulation can be controlled reliably.

[0024]

As described above, according to the present invention, the force of the diaphragm of the pressure reducing valve is applied from the back pressure chamber side to the secondary pressure side in adjusting the flow rate and pressure of the pressure reducing valve using the solenoid valve. However, since the pressure P _{N in the} back pressure chamber always advances in a decreasing direction, P _N > P _O does not occur. Therefore, there is an effect that stable control can be realized and performance can be improved.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram showing one embodiment of a pressure reducing valve adjusting device according to the present invention.

FIG. 2 is a diagram for explaining the operation of the present embodiment.

FIG. 3 is a waveform diagram of a pulse signal for driving each solenoid valve in the present embodiment.

FIG. 4 is a basic configuration diagram of a carrier gas flow control device according to the related art.

FIG. 5 is a schematic diagram showing an example when a normal mechanical setting type pressure reducing valve is applied to a gas chromatograph.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 pressure reducing valve 2 pressure sensor 4 CPU (controller) 5 carrier pressure control unit 6 drive gate unit 7 solenoid valve drive unit 11 inner chamber 11A pressure chamber 11B back pressure chamber 12 diaphragm 13 carrier gas supply flow path 14 carrier gas discharge flow path 15 Pivot valve 16, 17 Compression coil spring 18a Back pressure flow path 18b Flow path 20 Fixed throttle 21 Inlet / outlet of back pressure chamber 22 First supply solenoid valve 23 Second discharge solenoid valve

Claims (1)

(57) [Claims] 1. An inner chamber, and the inner chamber is connected to an upper back pressure chamber and a lower pressure chamber.
Diaphragm that separates the pressure chamber into two chambers.
Of the pressure chamber on the side opposite to the back pressure chamber and the discharge chamber on the side of the back pressure chamber.
A partition that divides the chamber into two chambers,
Gas supply flow path and gas discharge flow respectively connected to the outlet
Road and the diaphragm connected to the diaphragm
The formed flow hole is urged by a first spring,
The supply so as to open and close the flow hole according to the pressure of the chamber
A valve body disposed in the chamber, a second spring having a higher spring pressure than the first spring provided in the back pressure chamber to press the diaphragm toward the pressure chamber, and the gas discharge flow. A pressure reducing valve composed of a back pressure flow path that is communicated through a throttle between the passage and the entrance and exit of the back pressure chamber; and a pressure reducing valve disposed between the throttle of the back pressure flow path and the gas discharge flow path . A second supply solenoid valve, one end of which is communicated with a back pressure passage between the first supply solenoid valve and the throttle, and the other end of which is disposed in a passage open to the atmosphere. A discharge solenoid valve, a pressure sensor for detecting a secondary pressure of the pressure reducing valve, a detection value of the pressure sensor is compared with a preset reference value, and the first and second values are determined based on the comparison result. Control means for controlling the opening and closing of the solenoid valve to keep the secondary pressure of the pressure reducing valve constant, Pressure reducing valve, and the secondary pressure P _O, the pressure in the back pressure chamber P _N, the spring pressure of the first spring k, the spring pressure of the second spring and K (where K> k), the equilibrium A pressure-reducing valve adjusting device characterized by satisfying a formula of _PN + K = _PO + k when in a state.