JPH0379656B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention is useful for detecting the pressure difference between the upstream side and the downstream side that occurs when fluid passes through an element such as a filter element, and checking the progress of pressure loss in the element. This invention relates to a small and simple differential pressure detector used for.

In general, conventional differential pressure detectors can only detect in two stages, whether the differential pressure between the high pressure side fluid and the low pressure side fluid is lower or higher than a predetermined set value. It was not possible to detect when the vehicle was approaching and issue an alarm. Furthermore, once the differential pressure has been detected to have exceeded the set value, it does not automatically return to its original state even if the differential pressure returns to below the set value, and therefore a manual return operation is required each time, which is troublesome.

This invention was made in view of the above circumstances, and its purpose is to achieve three stages: a state in which the differential pressure is further below a predetermined pressure than a set value, a state in which the differential pressure approaches the set value, and a state in which the differential pressure exceeds the set value. To provide a very simple and highly practical device that can detect and issue a warning alarm, as well as automatically return to the original state when the differential pressure decreases. There is a particular thing.

In other words, the differential pressure detector of the present invention includes a differential pressure chamber inside a casing made of a non-magnetic material, and
A rod device chamber is provided with a partition wall adjacent to one end in the axial direction of the differential pressure chamber, and a spool having a magnet is provided in the differential pressure chamber and is tightly slidably fitted so as to be able to reciprocate in the axial direction. Additionally, a first spring is provided which always presses the spool with a magnet toward one end in the axial direction within the differential pressure chamber, and an inflow hole through which the high pressure side fluid flows from the spool in the differential pressure chamber to the one end in the axial direction; The casing is provided with an inflow hole through which a low-pressure fluid flows in from the spool in the differential pressure chamber to the other end in the axial direction, and the rod is reciprocated in the axial direction within the rod device chamber, and is magnetically operated by the magnet of the spool. A movable rod for detecting differential pressure is provided which is sucked toward the other end in the axial direction within the rod device chamber, and
A second spring is provided that constantly presses the movable rod toward one end in the axial direction of the rod device chamber, and the high-pressure fluid flows from each inlet hole into the one end and the other end in the axial direction from the spool in the differential pressure chamber. When the differential pressure with the low-pressure side fluid further decreases from the set value to a predetermined pressure or less, the pressing force of the first spring moves the spool toward one end in the axial direction of the differential pressure chamber, so that the spool is moved toward one end in the axial direction of the differential pressure chamber. The movable rod is held in the neutral position by the attraction force of the magnet and the pressing force of the second spring opposing this, and as the differential pressure increases and approaches the set value, the first
While the spool moves toward the other end in the axial direction of the differential pressure chamber against the pressing force of the spring, the suction force of the magnet causes the movable rod to follow the other end in the axial direction of the rod mounting chamber against the pressing force of the second spring. When the differential pressure further rises and exceeds the set value, the spool resists the pressing force of the first spring and moves further toward the other end in the axial direction of the differential pressure chamber, causing the rod to move against the movable rod in the rod device chamber. The pressing force of the first and second springs and the magnet are adjusted such that the suction force of the magnet becomes weaker and the movable rod moves from the neutral position in the rod mounting chamber toward one end in the axial direction due to the pressing force of the second spring. With the configuration in which the suction force is set, due to fluctuations in the differential pressure between the high-pressure side fluid and the low-pressure side fluid in the differential pressure chamber, the movable rod for differential pressure detection in the rod mounting chamber moves between the neutral position, one end in the axial direction, and the other end. This movement can be detected visually by coloring the movable rod or electrically by means of limit switches, relays, etc.
The differential pressure can now be detected in three stages.

An embodiment of the present invention will be described below with reference to the drawings. In the figure, 1 is a casing, which is attached coaxially to the head case 2 and the inner periphery of the threaded cylinder part 2a that protrudes integrally from the lower surface of the head case 2, and has an open top and a bottom. An inner shell 3 has a cylindrical shape, and an O-ring is attached to the outer periphery of the threaded cylindrical portion 2a of the head case 2 at its upper end, forming a cylindrical shape with a bottom that is one size larger than the inner shell 3 and fitting onto the outer periphery of the inner shell 3. The outer shell 5 is attached by screwing together with the outer shell 4 interposed therebetween. The head case 2 and inner and outer shells 3 and 5 of the casing 1 are all molded from non-magnetic material such as hard plastic.

Here, the inside of the inner shell 3 on the lower surface side of the head case 2 of the casing 1 is a differential pressure chamber 6, and the upper head case 2, which is one end in the axial direction, has a large diameter recess formed in the center of the upper surface, into which the rod is attached. The rod mounting chamber 7 and the differential pressure chamber 6 are adjacent to each other on the same axis with a partition wall 8 interposed therebetween. A small-diameter concave portion 8a that projects toward the differential pressure chamber 6 in a thin manner is integrally formed in the center of the partition wall 8 (bottom wall portion of the head case 2).

Further, the inner and outer shells 3 and 5 of the casing 1 are provided with inflow holes 9 and 10 for introducing high-pressure fluid A from the outside into the differential pressure chamber 6 and above the spool 15, which will be described later, at one end in the axial direction. In addition, inflow holes 11 and 12 are formed for introducing low-pressure side fluid B from the outside to the lower side, which is the other end side in the axial direction, than the spool 15 in the differential pressure chamber 6. Hereinafter, for convenience of explanation, one end in the axial direction will be referred to as an upper side, and the other end in the axial direction will be referred to as a lower side. Note that the high-pressure fluid inflow side and the low-pressure fluid inflow side of the gap between the inner and outer shells 3 and 5 are closely separated by an O-ring 13.

Inside the differential pressure chamber 6 of the casing 1, an aluminum spool 15 fitted with an O-ring 14 having a small friction coefficient on its outer periphery slides tightly against the inner peripheral surface of the differential pressure chamber 6 and can freely reciprocate up and down. A cylindrical magnet (permanent magnet) 16 is fixed coaxially to the upper surface of the spool 15. Note that this cylindrical magnet 16 is connected to the spool 15.
When moving upward, the partition wall 8 comes to a position surrounding the outer periphery of the central concave portion 8a of the partition wall 8 with a gap therebetween. At this time, the upper end of the magnet 16 comes into contact with the lower surface of the partition wall 8;
Since the magnet 6 itself is made by sintering and has many irregularities (not shown) on its surface, there is always a gap between the upper end surface of the magnet 16 and the lower surface of the partition wall 8 due to the irregularities. The high-pressure fluid A from the inflow holes 9 and 10 also flows into the cylindrical magnet 16 through the gap, and the fluid pressure acts on the upper surface of the spool 15, causing the inflow holes 11 and 1 to flow into the cylindrical magnet 16.
2 to the lower surface side of the spool 15 in the differential pressure chamber 6.

Further, a first spring 17 made of a compression coil spring is provided between the lower surface of the spool 15 in the differential pressure chamber 6 and the bottom surface of the inner shell 3, so as to always press the spool 15 upward. There is.

Next, in the rod device chamber 7 of the head case 2 of the casing 1, there is a movable rod 18 for differential pressure detection.
is installed so that it can move up and down. This movable rod 18 is made of aluminum and has a magnetic part 18a made of a permanent magnet at its lower end. The flange portion 18b has a flange portion 18b for receiving a spring, and is always pressed upward by a second spring 19 made of a tapered coil spring provided on the lower surface side of the flange portion 18b. The upper half of the movable rod 18 is a small-diameter knob 18c, and colored markings 18d and 18e, for example, blue and red, are applied to the upper and lower halves of the knob 18c by baking coating on the outer periphery of the knob 18c. A decorative plate 20 having a hole in the center through which the knob 18c can be inserted and retracted is attached to the upper surface of the rod device chamber 7 of the head case 2, and is pressed by a leaf spring 21. A plastic cover 22 is attached with screws.

To describe the operation of the differential pressure detector configured as described above, the high pressure side fluid A flows into the spool 15 in the differential pressure chamber 6 via the inlet holes 9 and 10 of the inner and outer shells 3 and 5 of the casing 1. into the upper side, and the low pressure side fluid B is inflow hole 1
1 and 12 into the lower side of the spool 15 in the differential pressure chamber 6. Here, if the differential pressure between the high-pressure side fluid A and the low-pressure side fluid B is small and is below a predetermined pressure from the set value, the spool 15 together with the magnet 16
moves to the upper end side as shown in FIG. 1 due to the elastic pressure of the first spring 17, and the magnetic force of the magnet 16 attracts the magnetic part 18a at the lower end of the movable rod 18 and pulls it downward against the second spring 19.
As a result, the movable rod 18 is held in the neutral position shown in FIG.
In this state, the worker should remove the knob 18c from outside the cover 22.
Only the blue color display 18d in the upper half part is visible, and it can be confirmed that the differential pressure is lower than the set value and lower than the predetermined pressure.

Next, when the differential pressure increases and approaches the set pressure, the spool 15 begins to move toward the lower end against the second spring 17 due to the differential pressure, and the magnet 16 integrated with the spool 15 moves toward the lower end of the movable rod 18. It descends while attracting the lower end magnetic portion 18a. This is the second
As shown in the figure, the movable rod 18 is connected to the second spring 1.
9, the upper knob 8c descends deeply into the central concave portion 8a of the partition wall 8 without changing the distance to the magnet 16, and the upper knob 8c sinks into the lower side of the decorative plate 20, and the blue colored display is displayed. 8d
becomes invisible. This allows the operator to confirm that the differential pressure has risen close to the set value.

If the differential pressure above rises further and exceeds the set value,
The spool 15 moves together with the magnet 16 against the first spring 17 and further moves toward the other end, thereby increasing the distance between the lower end of the movable rod 18 and the magnetic part 18a so that the magnet 16 comes off the outer periphery of the recessed part 8a downward and away from it. becomes farther away, and as a result, the balance between the magnetic attraction force between the magnet 16 and the magnetic part 18 and the elastic force of the second spring 19 is lost, and the elastic force of the second spring 19 causes the movable rod 18 to
is moved toward the upper end as shown in FIG. 3, and the flange portion 18b comes into contact with the lower surface of the decorative plate 20 and stops. Now the knob 18c is the decorative plate 20
The colored displays 18d and 18e are projected upward to the maximum extent and are visible from the outside in both blue and red, allowing the worker to confirm that the differential pressure is above the set value.

In this way, by detecting the differential pressure between the upstream and downstream sides of an element such as a filter element through which fluid passes, the pressure loss (degree of clogging) of the element can be adjusted to a normal state and a set value that is an allowable limit. It can be divided into three stages: an alert state that is close to a set value, and an unusable state that exceeds a set value, and it is convenient to perform or prepare for regeneration, repair, or replacement of the element in the above-mentioned alert state. Become.

Moreover, when the differential pressure decreases from the state shown in FIG. 3 and returns to below the predetermined pressure, the spool
is pushed up by the first spring 17 and rises together with the magnet 16 to approach the magnetic part 18a of the movable rod 18, which attracts the movable rod 18 and descends against the second spring 19 to move to the first
It will automatically return to the neutral position shown in the figure.

The present invention is not limited to the above-mentioned embodiments. For example, the casing 1 is composed of three members: the head case 2, the inner shell 3, and the outer shell 5. A part of the main body casing of the measuring instrument may be used, or the outer shell 5 may be omitted and the instrument consists of only the head case 2 and inner shell 3, or the head case 2 and inner shell 3 (excluding the bottom plate part) may be used. ) may be integrally molded, and a separate bottom plate portion may be attached to the lowermost end by screwing or the like.

Further, the second spring 19 may be a normal coil spring instead of a tapered coil spring.

Furthermore, the magnetic portion 18a of the movable rod 18 does not necessarily need to be a permanent magnet, but may be made of a material that can be attracted by a magnet.

In addition, the magnet 16 is used as a bar to move the movable rod 1.
The magnetic part 18a of 8 is made cylindrical, and the concave part 8 of the partition wall 8
a may be formed so as to protrude upward (toward the rod device chamber 7 side).

Furthermore, the upper knob 18c of the movable rod 18 is provided with colored markings 18d and 18e so that the worker can visually see the movement of the rod 18 in three stages and detect the differential pressure. It is also possible to electrically detect the movement in the three stages of 18 using various switches or a non-contact sensor, and notify the driver's cabin of a control center or the like using a lamp display or an alarm sound based on the electrical signal.

Since this invention is made as described above, the differential pressure between the high-pressure side fluid and the low-pressure side fluid is detected in three stages: a state in which the differential pressure between the high-pressure side fluid and the low-pressure side fluid is below a predetermined pressure, a state in which the pressure is close to the set value, and a state in which the differential pressure between the high-pressure side fluid and the low-pressure side fluid is below the set value. This makes it possible to issue a warning alarm, and it is also possible to automatically return to the original state when the differential pressure decreases, making it very simple and highly practical.

[Brief explanation of drawings]

The drawings show one embodiment of the invention.
The figure is a cross-sectional view showing the situation when the differential pressure is further below the set value, Figure 2 is a cross-sectional view when the differential pressure approaches the set value, and Figure 3 is a cross-sectional view when the differential pressure is higher than the set value. FIG. 1...Casing, 2...Head case, 2a
...Threaded cylinder part, 3 ... Inner shell, 4 ... O-ring, 5
... Outer shell, 6 ... Differential pressure chamber, 7 ... Rod device room,
8... Partition wall, 8a... Concave portion, 9, 10, 11,
12...Inflow hole, 13, 14...O ring, 15
... Spool, 16 ... Magnet, 17 ... First spring, 18 ... Movable rod, 18a ...
Magnetic part, 18b...Flange part, 18c...Small diameter knob, 18d, 18e...Colored display, 19...Second spring, 20...Decorative plate, 21...
Leaf spring, 22...cover.

Claims (1)

[Claims] 1 A differential pressure chamber is provided in a casing made of a non-magnetic material, and a rod device chamber is provided with a partition wall adjacent to one end in the axial direction of the differential pressure chamber, and a rod device chamber is provided in the differential pressure chamber in a reciprocating manner in the axial direction. A spool that is movably and closely fitted and has a magnet is provided, and a first spring that constantly presses the spool with the magnet toward one end in the axial direction within the differential pressure chamber, The casing is provided with an inflow hole through which high-pressure fluid flows into one end in the axial direction, and an inflow hole through which low-pressure fluid flows into the other end in the axial direction from the spool in the differential pressure chamber. A movable rod for differential pressure detection is provided which is capable of reciprocating in the axial direction and which is magnetically attracted toward the other end in the axial direction within the rod device chamber by the magnet of the spool, and the movable rod is always connected to the rod device chamber. A second spring is provided that presses toward one end in the axial direction, and the differential pressure between the high-pressure fluid and the low-pressure fluid that flow from the respective inflow holes to the spool in the differential pressure chamber to the one end and the other end in the axial direction is set. When the pressure drops further below the predetermined value, the spool is moved toward one end in the axial direction of the differential pressure chamber by the pressing force of the first spring, and the movable rod in the rod device chamber is moved by the attraction force of the magnet. The pressing force of the second spring resists this and holds it in the neutral position, and as the differential pressure increases and approaches the set value, the spool resists the pressing force of the first spring and moves toward the other end in the axial direction of the differential pressure chamber. While moving, the movable rod is moved and held by the suction force of the magnet against the pressing force of the second spring to the other end in the axial direction within the rod mounting chamber, and when the differential pressure further increases and exceeds the set value. The spool moves more toward the other end in the axial direction of the differential pressure chamber against the pressing force of the first spring, and the attraction force of the magnet against the movable rod in the rod device chamber weakens, causing the movable rod to move due to the pressing force of the second spring. A differential pressure detector characterized in that the pressing force of the first and second springs and the suction force of the magnet are set so as to move the rod from the neutral position in the rod mounting chamber to one end in the axial direction.