JPH0612241Y2 - Bladder type accumulator with intermediate sensor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an accumulator used for accumulating and buffering a pressure liquid, and more specifically, for the allowable compression limit failure of a bladder or the injection gas pressure during operation. The present invention relates to a bladder accumulator with an intermediate sensor that can detect a decrease. 2. Description of the Related Art In a bladder accumulator, a bladder divides the inside of a container body into a gas chamber and a liquid chamber, and a liquid is allowed to flow in and out of the liquid chamber against a gas pressure of the gas chamber. However, the liquid pressure in the liquid chamber exceeds the allowable limit, or
If the gas pressure drops due to gas leakage in the gas chamber, liquid above the specified volume will enter the container body, causing the bladder to contract beyond the allowable compression limit, and eventually to the air supply port of the gas chamber. It may be pushed in and damaged. Therefore, in order to prevent such an accident, a bladder type accumulator with a shutter type sensor is used. (See Japanese Utility Model Laid-Open No. 62-100302) In this accumleha, a holder protruding into a bladder and both foot ends of a U-shaped optical fiber housed in the holder are fixed to an upper side plate of a container body. A shutter is provided in the middle of the optical fiber, and one drive unit of the shutter is provided on the outer peripheral portion of the holder. When the allowable compression limit of the bladder is reached, the shutter drive unit is pressed by the bladder to close the shutter. Therefore, the light of the light emitting portion is blocked and does not enter the light receiving portion, so that the switch is activated and it is detected that it is out of the allowable compression limit. Problems to be solved by the invention The bladder of the bladder accumulator deforms under the influence of buoyancy and liquid pressure.In the first deformation stage, the bottom of the bladder rises in the axial direction, and in the second deformation stage, the bladder fluctuation part It has the property of shrinking in the radial direction. However, in this radial contraction, the fluctuating portion of the bladder does not always deform symmetrically on the circumference. Therefore, the left variation portion may approach the outer peripheral portion of the holder earlier than the right variation portion. In the bladder accumulator of the conventional example, the drive unit of the shutter is provided on the right side variable unit side, so in the above case, the variable unit does not press the shutter drive unit even when the allowable compression limit of the bladder is reached. There is. In consideration of the above circumstances, the present invention is based on the allowable compression limit of the bladder,
The purpose is to reliably detect a damage or a decrease in injection gas pressure during operation. The present invention relates to an accumulator arranged in a hydraulic circuit equipped with a pressure switch for detecting an upper limit value and a lower limit value of a hydraulic pressure, the accumulator being provided on an upper end of a cylindrical container body. An upper side plate; a bladder provided concentrically inside the container body, the body including a flange portion, a thick columnar portion formed in the axial direction, and a thin variable portion And a bladder composed of a bladder bottom portion; a holder provided so as to project into the bladder, an upper end portion of which is fixed to an upper side plate, and a lower end portion of which is located at an intermediate portion of the container body; A detector provided at the lower end of the holder so as to face the bottom of the bladder, located in the movement trajectory of the fluctuation part of the bladder, and operating at a pressure value between the upper limit value and the lower limit value of the hydraulic pressure. hand,
A bladder-type accumulator with an intermediate sensor, comprising: a detector having a protector having a diameter larger than that of the holder; and a detector having a switch operated by movement of the detector valve; It is a thing. When liquid is supplied into the bladder from the supply / discharge port, the bladder will
After moving up in the axial direction, the changing portion is deformed in the radial direction. Then, when the allowable compression limit of the bladder is reached, the fluctuating part moves the shutter valve of the detector while pushing it up to operate the switch, and notifies that the limit time has been reached. Also, if this shutter valve is set to a position where it operates at an operating pressure, for example, a pressure value between an upper limit value and a lower limit value, the injection gas pressure can be increased or decreased by interlocking with the upper and lower limit pressure switches on the hydraulic circuit. Can be detected. Embodiment An embodiment of the present invention will be described with reference to the accompanying drawings, and the same reference numerals have the same names and functions. The container body 1 is formed of a rigid material such as metal, and both ends thereof are covered with an upper side plate 2 and a lower side plate 3. The inside of the container body 1 is partitioned into a gas chamber A and a liquid chamber B by a bladder 4 arranged concentrically. The bladder 4 is formed of a flexible elastic material such as rubber, and includes a flange portion 5, a body portion 6, and a bladder bottom portion 7. The flange portion 5 is sandwiched between the container body 1 and the upper side plate. The body portion 6 is composed of a thick columnar portion 8 formed in the axial direction and a variable portion 9 formed thin. The bladder bottom portion 7 is also formed to be thick, and the bladder bottom portion 7 and the columnar portion 8 have a first shape when reduced from the original shape of the bladder.
It is formed so as to be in the state shown in FIGS. 4, 5 and 8. The upper side plate 2 has a cylindrical holder 1 protruding into the bladder.
The upper end 10a of 0 is fixed, and the lower end 10b thereof faces the bladder bottom 7. A detector 12 is provided at the lower end 10b of the holder. As shown in FIGS. 1 to 3, the detector 12 includes a shutter valve 13 concentric with the container body 1, side beam attachments 14 and 15 facing each other through a shutter space E, a light emitting port 16 and a light receiving port, respectively. Optical fiber 1 connected to 17
8 and 19, and a photoelectric switch 20 connected to the light emitting port 16 and the light receiving port 17. An elastic protector 21 is superimposed on the valve portion 13a of the shutter valve 13 in order to prevent damage to the bladder 4.
The shutter valve 13 is pressed downward by the spring 22, that is, to the bladder bottom portion 7 side, but the elastic force of the spring 22 is
It is regulated by a stopper 23 provided on the upper end of the shaft portion 13b. The lower side plate 3 is provided with a liquid inlet / outlet 24, and this inlet / outlet 24 is opened and closed by a valve 25. In the drawing, 26 is a valve portion, 27 is a spring, 28
Is a fiber adapter, 29 is a gas supply / discharge port, 30, 31
Indicates a gas passage, and an arrow indicates a fluid flow direction. When the gas is injected from the supply / discharge port 29, the gas is supplied to the holder 10
The bladder 4 is inflated by entering the gas chamber A through the passages 30 and 31. The bladder 4 is in close contact with the inner wall surface 1a of the container body 1 as shown in FIG.
Is pressed downward to close the valve 25. This gas is injected until the inside of the bladder 4 reaches a predetermined pressure. Next, when the pump 83 is operated and the liquid in the tank (not shown) is press-fitted into the inlet / outlet port 24, the bladder 4 rises in the axial direction by the buoyancy and the liquid pressure. Then, when the bladder bottom 7 rises to a predetermined position,
The bladder 4 has a natural shape as shown in FIG. 1A2 and does not further rise in the axial direction. Further, when the liquid pressure increases, the bladder 4 is deformed in the radial direction and its cross section becomes a star shape as shown in FIG. 4, and finally,
As shown in FIG. 5, the moving parts 9 facing each other come into contact with each other. Along with this, the changing unit 9 changes from the state of A3 in FIG. 1 to the state of A4. The state of A3 in FIG. 1 is within the allowable compression limit or within the set oil amount, and since the changing portion 9 does not contact the protector 21, the shutter valve 13 maintains the open state as shown in FIG. To do. Therefore, since the shutter space E is opened at this time, the light from the light emitting port 16 passes through the optical fiber 18 and the side beam attachment 14, enters the side beam attachment 15 and the optical fiber 19, and enters the light emitting port 17. Since the light is received, the photoelectric switch 20 does not operate. The state of A4 in FIG. 1 is a state in which the gas in the gas chamber A leaks due to permeation or the like and exceeds the allowable compression limit of the bladder 4. In this state, the protector 21 is pushed up in the axial direction, so that the shutter valve 13 , As shown in FIG. 3, it is in a closed state. Therefore, at this time, since the shutter space E is closed, the light from the light emitting port 16 is blocked by the shutter valve 13 and does not reach the light receiving port 17, so that the photoelectric switch 20 operates and the allowable compression limit of the bladder is reached. Notify you that you have reached. Further, when the bladder is damaged, liquid enters the gas chamber A and the shutter space E is closed by the liquid.
0 works. When the liquid does not enter the gas chamber A even if the bladder is damaged, the bladder 4 is deformed beyond the allowable compression limit due to the decrease in gas pressure, so the shutter valve 13 is closed and the photoelectric switch 20 is in the operating state. Therefore, the bladder 4 can be found to be damaged. The detector 12 is placed within the working pressure range of the accumulator ACC, and the minimum pressure at which the bladder is compressed and the accumulator ACC starts to operate, that is, the lower limit value is, for example, 50 kg.
/ cm ² , or the maximum pressure when the bladder is compressed to the maximum allowable value, that is, if the upper limit value is 150 kg / cm ² , the detector operates at an intermediate value, for example, 120 kg / cm ² . The lower limit value of the pressure switch 82 of the hydraulic circuit 81 is set to the lower limit value of the accumulator ACC, for example, 50 kg / cm ^2, and the upper limit value is set to the upper limit value of the accumulator ACC, for example, 150 kg / cm ² . can do. With this configuration, when the accumulator ACC is normal, when the hydraulic pressure sequentially reaches the lower limit value, the intermediate value, and the lower limit value as the hydraulic pressure in the hydraulic circuit 81 rises, the lower limit pressure switch, the detector, and the upper limit pressure are detected. The switch operates in this order. When the accumulator ACC is abnormal, it does not operate in the above order. That is, when the gas pressure in the gas chamber drops below the set pressure due to damage to the bladder, the accumulator ACC is at a lower pressure than normal, for example, at 40 kg / cm ² , the fluctuating portion of the bladder is pressed against the protector of the detector 12. , Activate the detector. Therefore, since the detector operates before the lower limit switch 82 operates, it is possible to detect that the gas pressure in the gas chamber has dropped below the set pressure. When the gas pressure in the gas chamber becomes higher than the set pressure, such as when the gas pressure rises due to temperature rise or when the gas is overfilled, a larger pressure than that when the accumulator ACC is normal, for example, 160 kg / cm ² Otherwise, the fluctuating part of the bladder does not press against the protector of the detector 12. Therefore, even if the fluid pressure becomes 150 kg / cm ^{2 and the} upper limit switch 82 operates, the detector still does not operate.
It is possible to detect that the gas pressure in the gas chamber is higher than the set pressure. Other Embodiments The embodiments of the present invention are not limited to the above,
For example, the detector may be configured as shown in FIGS. 6 and 7. Hereinafter, this embodiment will be described, but since the parts other than the detector are the same as those in the above embodiment, detailed description thereof will be omitted. The detector is a reflection table 77 which is concentric with the container body, and a space M.
Optical fibers 75 and 79 which are connected to the light emitting port 16 and the light receiving port 17 respectively by lens attachments 73 and 78 which are opposed to the reflecting table 77 via and have the same deflection angle with respect to the central axis C of the reflecting table 77. , A photoelectric switch 20 connected to the light emitting port 16 and the light receiving port 17. The reflecting table 77 is provided on the upper end of the shaft portion 13b and reflects the light from the lens attachment 73. The reflecting table 77 also functions as a stopper for the valve portion 13a. That is, the valve portion 13a descends downward due to gravity, that is, toward the bladder bottom portion 7 side, but when the valve portion 13a descends to a predetermined position, the reflecting base 77 contacts the support 80, so
The descent of 3a is prevented. The light 11 emitted from the photoelectric switch 20 is emitted from the light emission port 16,
The light passes through the optical fiber 75 and the lens attachment 73, hits the reflection table 77, and is reflected. At this time, since the valve portion 13a is descending as shown in FIG. 6, the reflected light 12 does not enter the lens attachment 78. Therefore, since the reflected light 12 does not reach the light receiving port 17, the photoelectric switch 20 does not operate. Next, when the liquid pressure increases and the bladder 4 deforms, the bladder bottom portion 7 rises in the axial direction, but when it reaches the lower limit of the allowable compression limit of the bladder, its movement is stopped and the state becomes B2. At this time, since the bladder bottom portion 7 pushes up the valve portion 13a,
The reflecting table 77 rises, but stops when the valve portion 13a comes into contact with the lower end portion 10b of the lower end portion 10b of the holder 10. At this time, the optical axis of the light 11 and the optical axis of the reflected light 12 are axially symmetrical with respect to the central axis line c of the reflecting table 77. Therefore, the light l1
The reflected light 12 of (1) passes through the lens attachment 78, the optical fiber 79, and the light receiving port 17 to activate the photoelectric switch 20 to notify that the bladder 4 has reached the allowable compression limit. When the bladder 4 is damaged, the liquid flows into the gas chamber A. If the liquid allows light to pass, the photoelectric switch 20
Does not work. However, when this liquid comes into contact with the reflecting table 77, the reflected light 12 enters the lens attachment 78 due to the refraction between the gas and liquid, so that the photoelectric switch 20 operates. Furthermore, the detector may be configured as shown in FIG.
That is, the rod 32 is fixed to the shaft portion 13B of the moving valve 13A of the detector 12A, and the actuator 33 is attached to the upper end portion of the rod 32.
For example, a magnet is provided, and the magnetic switch 34 is provided near the movement locus of the actuator 33. Then, when the moving valve 13A is closed and the actuator 33 is moved to the position 33A indicated by the chain line, the switch 34 is activated to notify that the allowable compression limit has been reached. Effect of the Invention Since the present invention is configured as described above, it has the following remarkable effects. (1) A detector that is located within the movement locus of the fluctuation portion of the bladder, and has a detection valve having a protector having a diameter larger than the diameter of the holder, and a switch that is activated by the movement of the detection valve. As the liquid in the accumulator rises, the fluctuation part of the bladder pushes up the detection valve. At this time, since the detection valve is provided with a large-diameter protector, damage to the bladder is prevented and the detection range is expanded. Pushing this detection valve up to a predetermined position will surely activate the switch of the detector. Therefore, it is possible to detect when the bladder is at the allowable compression limit or when it is damaged. (2) The bladder includes a flange portion, a body portion including a thick columnar portion formed in the axial direction and a thin variable portion, and a bladder bottom portion (referred to as a pleat bladder). Therefore, when deformed, it is regularly folded from the columnar part to form a star shape. Therefore, since the moving part of the bladder is moved within a predetermined range, the detection valve can be opened and closed with certainty. (3) A pressure switch for detecting the upper and lower limits of the hydraulic pressure, a holder whose lower end is located in the middle of the container body, and a lower end of the holder which is provided with the upper and lower limits of the hydraulic pressure. Since it has a detector that operates at a pressure value of between, the detector is placed within the working pressure range of the accumulator, and the minimum pressure at which the bladder is compressed to start the operation of the accumulator, that is, the lower limit value is, for example, 50 kg. / cm ² , or the maximum pressure when the bladder is compressed to the maximum allowable value, that is, if the upper limit value is 150 kg / cm ² , the detector operates at an intermediate value, for example, 120 kg / cm ² . The lower limit value of the pressure switch of the hydraulic circuit is set to the lower limit value of the accumulator, for example, 50 kg / cm ^2, and the upper limit value is set to the upper limit value of the accumulator, for example, 150 kg / c.
Can be set to m ² . In this way, when the accumulator is normal, when the hydraulic pressure sequentially reaches the lower limit value, the intermediate value, and the lower limit value as the hydraulic pressure in the hydraulic circuit increases,
The lower limit pressure switch, the detector, and the upper limit pressure switch operate in this order. However, when the accumulator is abnormal, it does not operate in the above order. That is, when the gas pressure in the gas chamber drops below the set pressure due to damage to the bladder, etc., the pressure is lower than when the accumulator is normal, for example, 40 kg / cm ² and the fluctuation part of the bladder presses against the protector of the detector and detects Activate the vessel. Therefore, since the detector operates before the lower limit switch operates,
It is possible to detect that the gas pressure in the gas chamber has dropped below the set pressure. In addition, when the gas pressure in the gas chamber becomes higher than the set pressure, such as when the gas pressure rises due to temperature rise or when the gas is overfilled, a higher pressure than when the accumulator is normal, for example, 160 kg / cm if is cry on ² variable portion of the bladder is not pressed against the protector of the detector. Therefore, even if the liquid pressure becomes 150 kg / cm ^{2 and the} upper limit switch operates, the detector still does not operate, and it is possible to detect that the gas pressure in the gas chamber is higher than the set pressure.

[Brief description of drawings]

1 to 5 are views showing an embodiment of the present invention. FIG. 1 is a longitudinal sectional view, FIGS. 2 and 3 are enlarged sectional views of the detector of FIG. 1, and FIG. FIG. 3 shows a state in which the shutter valve is open, FIG. 3 shows a state in which the shutter valve is closed, FIG. 3 shows a state in which the shutter valve is closed, FIG. 4 and FIG. FIG. 4 is a radial sectional view of the bladder, FIG. 4 is a diagram showing a deformed state at an initial stage, FIG. 5 is a diagram showing a deformed state at an allowable compression limit, and FIGS. 6 and 7 are other embodiments. 6 is a longitudinal sectional view showing FIG. 2, FIG. 7 is a diagram corresponding to FIG. 3, and FIG. 8 is a longitudinal sectional view showing still another embodiment. 1 ... Container body 2 ... Upper side plate 4 ... Bladder 7 ... Bladder bottom 9 ... Bladder moving part 10 ... Holder 10a ... Holder top 10b ... Holder bottom 12 ... Sensor

Claims (1)

[Scope of utility model registration request] 1. An accumulator arranged in a hydraulic circuit equipped with a pressure switch for detecting an upper limit value and a lower limit value of a hydraulic pressure; an upper side plate provided on an upper end of a cylindrical container body; A bladder provided concentrically inside the main body, comprising a flange portion, a body portion including a thick columnar portion formed in the axial direction and a thin variable portion, and a bladder bottom portion. A configured bladder; a holder that is provided so as to project into the bladder, the upper end of which is fixed to the upper side plate, and the lower end of which is located in the middle of the container body; and the bladder at the lower end of the holder. A detector which is provided facing the bottom portion, is located in the movement trajectory of the fluctuation portion of the bladder, and operates at a pressure value between the upper limit value and the lower limit value of the hydraulic pressure,
A bladder-type accumulator with an intermediate sensor, comprising: a detector having a protector having a diameter larger than that of the holder, and a detector having a switch operated by movement of the detector valve.