JP4451002B2 - Differential pressure valve - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a differential pressure valve (also referred to as a differential pressure control valve or an equilibrium valve) that adjusts the relative pressure of two separated gases, and more particularly to a vapor compression evaporation concentrator operated under reduced pressure. This differential pressure valve is preferably used in the range from normal pressure to negative pressure, and the differential pressure between the two gases is constant, that is, one gas pressure is higher than the other gas pressure by a constant pressure (or Low) to maintain the differential pressure valve.
[0002]
[Prior art]
A differential pressure valve that maintains the fluid pressure of one of two separated fluids at a constant high pressure has been known. For example, a balance valve disclosed in Japanese Patent Application Laid-Open No. 59-110968 is a valve body having a hole for accommodating a piston, receives the fluid pressure of the first and second fluids at both ends of the piston, and the differential pressure by the spring. Set and separated from each other by the piston, each fluid pressure system is provided with a relief passage connected to normal pressure, and the connection between each associated fluid pressure system and the relief passage is controlled by the movement of the piston This is a differential pressure valve.
[0003]
[Problems to be solved by the invention]
When using such a differential pressure valve in a pressurized state, it is possible to set the pressure difference with a spring, but when using it with negative pressure (by gauge pressure) by suction with a vacuum pump or the like. Since one gas pressure is a normal pressure, the other gas pressure gradually decreases (that is, the differential pressure increases), making it difficult to keep the differential pressure constant.
An object of the present invention is a differential pressure valve that can be used in a range of normal pressure to negative pressure, and can maintain a pressure of one of two separated gases at a constant high (or low) state. It is to provide a differential pressure valve.
[0004]
[Means for Solving the Problems]
In order to solve the above problems, the present invention has the following configuration.
That is, the differential pressure valve of the present invention is a differential pressure valve that adjusts the relative pressure of two separated gases,
A first pressure chamber 1 that is connected to the first gas (gas A: its absolute pressure is P1) and can be connected to the outside air communication port 3 via the first adjustment valve 8;
The diaphragm is connected to the second gas of the concentrator (gas B: its absolute pressure is P2), except for when the second regulating valve 9 is connected to the first animal pressure chamber 1 in an open state. It consists of a second pressure chamber 2 that is isolated across the valve 6,
The differential pressure (P1−P2) between the first livestock pressure chamber 1 and the second livestock pressure chamber 2 is the opening / closing of the first regulating valve 8 or the second regulating valve 9 associated with the movement of the diaphragm valve 6. A differential pressure valve that is constantly adjusted by an opening degree and an elastic body that presses the diaphragm valve 6.
[0005]
Here, the differential pressure adjusting unit in the differential pressure valve is preferably,
A shaft (transmission device) 7 is fixed perpendicular to the diaphragm valve 6,
The first spring 4 is attached to the first pressure chamber side of the diaphragm valve 6,
A second spring 5 is attached to the second pressure chamber side of the diaphragm valve 6,
The first spring 4 and the second spring 5 detect the pressure difference between the first pressure chamber and the second pressure chamber and move the shaft (transmission device) 7.
According to the movement of the shaft (transmission device) 7, the first adjusting valve 8 or the second adjusting valve 9 is opened or closed or its opening degree is adjusted.
[0006]
The first adjusting valve 8 and the second adjusting valve 9 are preferably a first pilot valve and a second pilot valve, respectively. These pilot valves are arranged at both ends of the shaft (transmission device) 7. To be placed outside.
The shape of the first or second pilot valve element may be a shape whose opening degree can be adjusted, for example, a piece shape or a spherical shape.
[0007]
Note that the first gas (gas A) and the second gas (gas B) are air, water vapor, various other gases, mixtures thereof, and the like, in which gaseous fine particles (mist) are mixed. It does n’t matter. The first gas pressure (P1; absolute pressure) is higher than the second gas pressure (P2; absolute pressure) in a normal use state, and the differential pressure (P1-P2) is about 0.2 atm. Is preferably maintained.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described more specifically with reference to the accompanying drawings.
FIG. 1 is a perspective view of a differential pressure valve according to an example of the present invention. The differential pressure valve is connected to the first gas pressure chamber 1 connected to the first gas (gas A; its absolute pressure P1) and introduced therein, and to the second gas (gas B; its absolute pressure P2). The first animal pressure chamber 1 is connected to the outside air communication port 3 via the first pilot valve element 8. A movable diaphragm valve 6 is interposed between the first and second pressure chambers 1 and 2, and a shaft (transmission device) 7 is fixed to the diaphragm valve 6 so as to be orthogonal thereto. ing. A first spring 4 is attached to the first pressure chamber side of the diaphragm valve 6, a second spring 5 is attached to the second pressure chamber side, and the second pressure chamber 2 is connected to the second pilot valve. When the child 9 is open, it is connected to the first animal pressure chamber 1, and when the second pilot valve 9 is closed, it is isolated from the first animal pressure chamber 1.
[0009]
The "equilibrium" action in the differential pressure valve of the present invention will be described with reference to FIG. The differential pressure between the first livestock pressure chamber 1 and the second livestock pressure chamber 2 is detected by the first spring 4 or the second spring 5, and at that time, P1 is higher than P2 by a predetermined pressure, that is, the differential pressure. When (P1-P2) is equal to or greater than a predetermined value, the diaphragm valve 6 moves to the left, and the shaft (transmission device) 7 fixed to the diaphragm valve 6 also moves to the left, and the first pilot valve 8 The second pilot valve element 9 is pushed open while being closed, and the first animal pressure chamber 1 and the second animal pressure chamber 2 are connected to each other, and a force is applied to eliminate the pressure difference between the two chambers. At this time, the opening degree is adjusted according to the degree of push-opening of the pilot valve element 9, and the pressure difference between the two chambers is balanced.
[0010]
When the pressure difference (P1-P2) is less than a predetermined value, the diaphragm valve 6 moves to the right, and the shaft (transmission device) 7 fixed to the diaphragm valve 6 also moves to the right, so that the second pilot While the valve 9 is closed, the first pilot valve 8 is pushed open, and the first pressure chamber 1 communicates with the outside air through the communication port 3 (P1 = atmospheric pressure). At this time, since the first animal pressure chamber 1 and the second animal pressure chamber 2 are isolated, the pressure (P2) of the second animal pressure chamber 2 is determined by the characteristics of the first spring 4 and the second spring 5. It becomes a predetermined value and is maintained in that state.
Thus, in the differential pressure valve of the present invention, the pressure (P1) in the first livestock pressure chamber 1 is maintained higher than the pressure (P2) in the second livestock pressure chamber 2 by a predetermined pressure.
[0011]
FIG. 2 is a connection example (horizontal sectional view) in which the differential pressure valve of the present invention is connected to a Roots type compressor in a vapor compression evaporation concentrator operating under reduced pressure. FIG. 3 shows the differential pressure valve of the present invention. The pressure in the oil chamber (gas A chamber) and the intermediate chamber (gas B chamber) in the installed Roots compressor and the time change of the pressure difference are shown.
The Roots compressor 20 is divided into an oil chamber (a chamber in which a part of the chamber is filled with oil) 22, an intermediate chamber 21, and a compression chamber 23, and the partition of each chamber is sealed with an oil seal ( However, a minute gap is inevitable in the oil seal). The oil chamber (gas A chamber) 22 of the roots compressor 20 and the first animal pressure chamber 1 of the differential pressure valve are connected, and the intermediate chamber (gas B chamber) 21 of the roots compressor 20 and the second animal of the differential pressure valve are connected. The pressure chamber 2 is connected, and the pressure in the oil chamber 22 is adjusted by a differential pressure valve so as to be higher than the pressure in the intermediate chamber 21 by a predetermined value.
[0012]
First, the compression chamber 23 is continuously depressurized. The chamber is depressurized in the order of the intermediate chamber 21 and the oil chamber 22 over time. When the roots compressor 20 is returned to normal pressure after a long operation, first, the compression chamber 23 is opened to normal pressure. As time passes, the intermediate chamber 21 and the oil chamber 22 return to normal pressure in this order. At this time, the vapor of the evaporative concentration apparatus enters the intermediate chamber, which condenses to become water. When the differential pressure valve is not connected, the condensed water flows out from the high pressure side to the low pressure side (that is, from the intermediate chamber 21 to the oil chamber 22), and the oil deteriorates due to the condensed water or the like, or the Roots compressor 20 The parts of the machine are rusted and the oil must be changed frequently. On the other hand, if the differential pressure valve of the present invention is used, the pressure on the oil chamber 22 side is always higher than the pressure on the intermediate chamber 21 both when the pressure is reduced from normal pressure and when the pressure is reduced and returned to normal pressure. Since it is maintained at a high state, condensed water or the like does not enter the oil chamber 22, and therefore, early deterioration of the oil is prevented.
[0013]
【The invention's effect】
The present invention is a mechanical differential pressure valve that can be used in a range of normal pressure to negative pressure, and in a state where the pressure of one of two separated gases is constantly high (or low). It is a differential pressure valve to maintain. Therefore, it is preferably used in a vapor compression evaporation concentrator operating under reduced pressure, and effectively prevents early deterioration of the oil of the roots compressor. Manufacturing costs and running costs are low.
[Brief description of the drawings]
FIG. 1 is a perspective view of a differential pressure valve according to an example of the present invention.
FIG. 2 is a connection diagram (horizontal sectional view) when the differential pressure valve of FIG.
FIG. 3 is a graph showing the pressure in the oil chamber (gas A chamber) and the intermediate chamber (gas B chamber) in the Roots-type compressor equipped with the differential pressure valve of the present invention, and the change over time in both pressure differences.
[Explanation of symbols]
1: First pressure accumulation chamber 2: Second pressure accumulation chamber 3: Outside air communication port 4: First spring 5: Second spring 6: Diaphragm valve 7: Shaft (transmission device)
8: First adjustment valve (first pilot valve)
9: Second adjustment valve (second pilot valve)
10: Cylinder 11: Presser foot 20: Roots type compressor 21: Intermediate chamber 22: Oil chamber 23: Compression chamber

Claims (3)

A differential pressure valve for adjusting the relative pressure of the two separated gases,
A first pressure chamber that is connected to the first gas (gas A) and can be connected to the outside air communication port via the first adjustment valve;
A second pressure chamber connected to a second gas (gas B) and separated from the first pressure reduction chamber with a diaphragm valve except when the second adjustment valve is connected in an open state ;
An elastic body that presses the diaphragm valve ;
If the pressure difference (P1-P2) between the pressure (P1) in the first pressure chamber and the pressure (P2) in the second pressure chamber is equal to or greater than a predetermined value, the diaphragm valve moves to the second pressure chamber side. The second regulating valve is opened, and when the differential pressure (P1-P2) is less than a predetermined value, the diaphragm valve moves to the first stocking pressure chamber side to open the first regulating valve. ,
The differential pressure between the first and second pressure chambers presses the diaphragm valve and opens or closes the first regulating valve or the second regulating valve accompanying the movement of the diaphragm valve. differential pressure valve which is regulated constant by said elastic member. A shaft is fixed perpendicular to the diaphragm valve, and as the elastic body,
A first spring for urging the diaphragm valve is provided on the first pressure chamber side of the diaphragm valve;
A second spring for urging the diaphragm valve from the opposite side is provided on the second pressure chamber side of the diaphragm valve;
The first spring and the second spring detect the differential pressure between the first pressure chamber and the second pressure chamber and move the shaft;
The differential pressure valve according to claim 1, wherein the opening and closing of the first adjustment valve or the second adjustment valve is adjusted in accordance with the movement of the shaft. The first adjustment valve and the second adjustment valve are respectively disposed outward of both ends of the shaft, and are opened / closed or adjusted in opening degree by being pushed by the movement of the shaft. The differential pressure valve according to claim 2, which is a valve element.

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