JP7005473B2 - Pilot governor - Google Patents

Description

The present invention relates to a pilot governor (pilot pressure regulator) used in a pressure regulator for gas pressure control and the like.

For example, in the middle of a supply path for city gas or the like, there is a place where the pressure in the pipeline is switched, and a pressure regulator called a governor is provided in that part.

The schematic configuration of the pressure regulator is shown in FIG. The pressure regulator in the figure includes a main governor 23, a pilot governor 1, an orifice 24, etc., which are incorporated between the primary side pipeline 21 and the secondary side pipeline 22 to reduce the high pressure on the primary side and flow it to the secondary side. It is included, and the change in the secondary pressure is suppressed to a small extent by adjusting the secondary pressure by these devices.

An example of the pressure regulator is shown in detail in, for example, Patent Document 1 below.

In the pilot governor 1 of FIG. 9, two diaphragms (upper diaphragm 3 and lower diaphragm 4) provided in the casing 2 are connected via a holder 5, and the upper diaphragm 3 and the lower diaphragm 4 (upper diaphragm 3 and lower diaphragm 4) are connected in the casing 2. Below, the drive pressure chamber (load pressure chamber) 6 located between the upper and lower diaphragms 3 and 4, the secondary pressure chamber 7 located above the upper diaphragm 3, and the large large chamber located below the lower diaphragm 4. The pressure chamber 8 is formed.

Further, an exhaust that switches the communication state between the introduction passage 9 for the control pressure fluid, the supply valve 10 installed at the outlet of the introduction passage 9 to the drive pressure chamber 6, and the drive pressure chamber 6 and the secondary pressure chamber 7. A valve 11 and a spring 12 capable of adjusting the urging force for urging the holder 5 from the atmospheric pressure chamber 8 side to the secondary pressure chamber 7 side are provided inside the casing 2.

The secondary pressure chamber 7 is connected to the balance pressure chamber 23b of the secondary side pipeline 22 and the main governor 23, and is incorporated in the middle of the path connecting the primary side pipeline 21 and the introduction passage 9 depending on the form of the pressure regulator. It is also connected to the pressure control chamber of the pressure reducing valve (not shown).

The introduction passage 9 is connected to the primary side pipeline 21, and the drive pressure chamber 6 is further connected to the loading pressure chamber (drive pressure chamber) 23c of the main governor 23.

The valve portion opening of the supply valve 10 is maintained constant at a position where the forces applied to the upper and lower diaphragms 3 and 4 are balanced.

In the pressure regulator that operates the main governor 23 using the pilot pressure of the exemplary pilot governor 1, the communication between the primary side pipeline 21 and the secondary side pipeline 22 is cut off by the on-off valve 23a of the main governor 23. When the pressure in the secondary pipeline is used and reduced below, the pressure in the secondary pressure chamber 7 of the pilot governor 1 is reduced.

Therefore, the balance of the forces applied to the upper and lower diaphragms 3 and 4 of the pilot governor 1 is lost, and the upper and lower diaphragms 3 and 4 are pushed by the spring 12 and move upward together with the holder 5, and the valve of the supply valve 10. The part opening becomes large.

As a result, the amount of the control pressure fluid introduced into the drive pressure chamber 6 from the primary side pipeline increases, and the pressure in the drive pressure chamber 6 (the drive pressure supplied to the main governor) increases.

The pressure in the drive pressure chamber 6 rises until the loading pressure reaches a predetermined pressure value, and when the loading pressure reaches a predetermined pressure value, the force applied to the upper and lower diaphragms 3 and 4 of the pilot governor 1 is again applied. By balancing, the upper and lower diaphragms 3 and 4 move downward with the holder 5 and are returned to the balance point.

At this time, the rising behavior of the loading pressure changes depending on the fluctuation of the mounting positions (mounted positions) of the upper and lower diaphragms 3 and 4.

This is because the pressure receiving conditions of the upper and lower diaphragms 3 and 4 change due to changes in the mounting positions.

On the other hand, the increased pressure in the drive pressure chamber 6 flows into the loading pressure chamber 23c of the main governor 23, and the pressure increase in the loading pressure chamber 23c due to this causes the valve portion opening of the on-off valve 23a to increase, so that the primary side The amount of high-pressure fluid flowing in the secondary side pipeline 22 increases, and the pressure in the secondary side pipeline 22 rises.

Along with this, the pressure in the secondary pressure chamber 7 of the pilot governor 1 also rises, and the supply valve 10 closes due to the increase in the pushing force applied to the upper diaphragm 3.

At the same time, the exhaust valve 11 opens and the pressure in the drive pressure chamber 6 escapes to the secondary pressure chamber 7, whereby the internal pressures of the balance pressure chamber 23b and the loading pressure chamber 23c of the main governor become equal to each other, and the main spring 23d The on-off valve 23a is closed by the force of.

In this way, the change in the pressure receiving status of the upper diaphragm 3 and the lower diaphragm 4 due to the change in the mounting position of the diaphragm means that the response characteristics of the pressure regulator to the change in the secondary pressure (usage amount) differ from individual to individual. do.

In order to correct the individual difference in the response characteristics, a characteristic adjustment mechanism as shown in FIG. 10 has been devised, and a similar mechanism is also shown in Patent Document 1 below.

The characteristic adjustment mechanism of FIG. 10 is such that the supply valve 10 is screwed into the holder 5 with a variable screwing amount, and the relative positions of the upper and lower diaphragms 3 and 4 are adjusted by adjusting the screwing amount.

The adjustment is performed by filling the secondary pressure chamber 7 with a gas of a predetermined pressure, inspecting the response characteristics of the pilot governor 1, comparing the characteristic values obtained by the inspection with the previously known reference characteristic values, and comparing the reference characteristics. The adjustment value of the screwing amount of the supply valve 10 with respect to the holder 5 is calculated based on the deviation from the value.

Then, the relative positions of the upper and lower diaphragms 3 and 4 are adjusted based on the calculated adjustment value of the screwing amount of the supply valve 10, and then the secondary pressure chamber 7 is refilled with the fluid for inspection at a predetermined pressure. The method is to re-inspect whether the relative positions of the upper and lower diaphragms 3 and 4 are adjusted correctly.

In the displacement from the position of FIG. 10 to the position of FIG. 11, the difference between the forces applied to the upper and lower diaphragms 3 and 4 facing each other becomes small, and in the displacement from the position of FIG. 11 to the position of FIG. 10, the force is reduced. The difference becomes large.

Japanese Unexamined Patent Publication No. 2006-285663

In the characteristic adjustment mechanism as shown in FIG. 10 which has been conventionally devised, a tool is inserted into the casing 2 from the secondary pressure introduction port P3 (see FIG. 9) provided on the crown of the casing of the pilot governor. Then, it is necessary to rotate the supply valve 10.

The work needs to be performed by opening the port P3 in order to insert the tool for the rotation operation, and since the internal pressure of the secondary pressure chamber 7 is released at that time, for the re-inspection performed after the adjustment. It takes a lot of time to refill the secondary pressure chamber 7 with the fluid pressure.

Further, according to the conventional characteristic adjustment mechanism, the radial inner end side of the upper and lower diaphragms is fixed to the holder, and the mounting position of the upper and lower diaphragms with respect to the holder changes at the same time in accordance with the displacement of the holder, so that the characteristics are finely adjusted. If it was painful and difficult.

Since the upper diaphragm 3 and the lower diaphragm 4 are mounted in opposite directions, a change in the pressure receiving condition due to a change in the mounting position of the inner ends of both diaphragms increases the force pushing the upper diaphragm 3 toward the secondary pressure chamber 7. Occasionally, the force pushing the lower diaphragm 4 toward the atmospheric pressure chamber 8 is reduced.

Therefore, the amount of change in the characteristics with respect to the screwing amount of the supply valve 10 with respect to the holder 5 is large, which makes fine adjustment difficult.

The present invention has been made in view of the above-mentioned current technology, and can correct individual differences in response characteristics to fluctuations in secondary pressure in a short time without releasing the internal pressure of the secondary pressure chamber. The challenge is to provide a pilot governor that can fine-tune the response characteristics.

In order to solve the above problems, in the present invention,
A casing that has a drive pressure chamber for introducing the primary pressure, a secondary pressure chamber for introducing the secondary pressure regulated by the main governor, and an atmospheric pressure chamber inside.
An upper diaphragm and a lower diaphragm arranged at intervals above and below the inside of the casing with the drive pressure chamber in between.
A holder that connects the upper diaphragm and the lower diaphragm,
A supply valve that combines a nozzle with a fixed position of an upward opening that introduces primary pressure into the drive pressure chamber and a seat packing that is in contact with and detached from the nozzle.
An exhaust valve provided in the upper diaphragm and interlocking with the supply valve to communicate the drive pressure chamber with the secondary pressure chamber.
It has a spring installed inside the atmospheric pressure chamber and capable of adjusting the urging force that urges the upper diaphragm and the lower diaphragm together with the holder toward the secondary pressure chamber side.
When the pressure in the secondary pressure chamber drops, the seat packing follows the displacement of the upper diaphragm and the lower diaphragm, and the valve portion opening of the supply valve increases. In this situation, the drive pressure chamber passes through the nozzle. It is a pilot governor that supplies the pressure introduced in the main governor as a driving pressure to the loading pressure chamber of the main governor.
It has an adjustment mechanism that changes the relative position of the upper diaphragm and the lower diaphragm.
The adjusting mechanism is composed of an adjusting ring fixed to the lower diaphragm and an adjusting screw rotatably attached to the adjusting ring with the rotation operation unit facing the atmospheric pressure chamber. It is screwed into the holder, the inner end side of the lower diaphragm is fixed to the adjustment ring, and by adjusting the screwing amount of the adjustment screw with respect to the holder, the lower diaphragm is attached to the fixing position of the lower diaphragm attached to the adjustment ring and to the holder. Provided is a pilot governor in which the relationship between the fixed positions of the upper diaphragm is changed.

The pilot governor uses the adjusting screw tool by including the casing with a lower cover covering the atmospheric pressure chamber and a cap closing the lower end opening of the lower cover, and removing the cap from the lower cover. All rotation operations can be performed.

In the pilot governor of the present invention, the adjusting mechanism includes a locknut that is screwed into the adjusting screw to fix the adjusting screw at a position where the screwing amount is adjusted, and the locknut is placed in the atmospheric pressure chamber. It is preferable that the adjusting ring can be in contact with the lower end surface.

Further, the holder has a boss portion protruding downward at the center of the lower end, and the adjustment ring has a recess for accepting the boss portion so as to be slidable in the axial direction, and a screw hole formed inside the boss portion. It is also preferable to have a structure in which the adjusting screw is screwed.

It is also preferable to maintain the receiving state of the boss portion by the recess at the position where the adjusting screw is pulled out from the boss portion (the position where the screw hole and the adjusting screw are unscrewed).

The pilot governor of the present invention has an adjustment mechanism that changes the relative position of the upper and lower diaphragms (= the position of the seat packing with respect to the nozzle of the supply valve), and the adjustment mechanism can be operated on the atmospheric pressure chamber side. It has become.

For this reason, it is possible to adjust the unavoidable relative position deviation due to machining errors at the positions where the upper and lower diaphragms are attached without releasing the pressure in the secondary pressure chamber, and to eliminate individual differences in response characteristics. Adjustment work becomes easy.

In addition, since the position of the diaphragm can be adjusted only by moving the lower diaphragm, the amount of change in response characteristics with respect to the screwing amount of the adjusting screw is smaller than that of the type of adjustment mechanism in which the upper and lower diaphragms move at the same time, which makes fine adjustment difficult. It becomes possible without accompanying.

If the adjusting mechanism includes a locknut that fixes the adjusting screw at the adjusted position of the screwing amount, it is possible to prevent an unintended change in the adjusting position due to loosening of the adjusting screw.

Further, the holder has a boss portion at the center of the lower end, and the adjustment ring has a recess for accepting the boss portion so as to be slidable in the axial direction. The adjusting screw is screwed into a screw hole formed in the boss portion. Since the boss portion and the recess provide the positioning effect and the guide effect of the holder and the adjusting ring, the connection of the upper and lower diaphragms via the holder and the displacement of the lower diaphragm by the operation of the adjusting screw are stable.

In addition, in the case where the adjusting screw is maintained in the receiving state of the boss portion by the concave portion at the position where the adjusting screw is pulled out from the boss portion, the adjusting screw is excessively operated and screwing with the boss portion is performed. Even if a situation occurs in which the boss portion is unraveled, the centering state of the boss portion and the adjusting screw is maintained, so that the adjusting screw can be easily re-screwed to the boss portion.

It is sectional drawing which shows the example of the pilot governor of this invention simplified. It is a top view of the lower diaphragm and the holder incorporated in the pilot governor of FIG. FIG. 2 is a cross-sectional view taken along the line XX of FIG. It is an enlarged perspective view of the fastening part which connected the holder of the assembly of FIG. 1, the adjustment ring and the adjustment screw. It is sectional drawing of the fastening part of FIG. 4 which shows the state which the adjustment ring is separated from the holder. It is sectional drawing of the fastening part of FIG. 4 which shows the state which the adjustment ring was moved to the holder side. It is a figure which shows the relative position of the upper and lower diaphragms at the position of FIG. It is a figure which shows the relative position of the upper and lower diaphragms at the position of FIG. It is a schematic block diagram which shows an example of the connection state of the main governor and the pilot governor of a pressure regulator. It is sectional drawing which shows the outline of an example of the conventional characteristic adjustment mechanism devised for adjusting the individual difference of the response characteristic to the fluctuation of the secondary pressure of a pilot governor. It is explanatory drawing of the characteristic adjustment method by the characteristic adjustment mechanism of FIG.

Hereinafter, embodiments of the pilot governor of the present invention will be described with reference to FIGS. 1 to 8 of the accompanying drawings.

The exemplary pilot governor 1 includes a casing 2, an upper diaphragm 3, a lower diaphragm 4, a holder 5, a drive pressure chamber 6, a secondary pressure chamber 7, an atmospheric pressure chamber 8, and a control pressure, each of which is formed inside the casing 2. It is composed of a combination of a fluid introduction passage 9, a supply valve 10, an exhaust valve 11, a spring 12, a pressure adjusting mechanism 13, an adjusting ring (adjusting ring) 14, an adjusting screw 15, and a locknut 16.

The casing 2 is a combination of a body 2a having a drive pressure chamber 6, an upper cover 2b covering the secondary pressure chamber 7, a lower cover 2c covering the atmospheric pressure chamber 8, and a cap 2d closing the lower end opening of the lower cover 2c. Things are used.

The body 2a has the introduction passage 9 and a port P1 connected to the loading pressure chamber of the main governor.

The upper cover 2b has a port P2 connected to the balance pressure chamber of the main governor and a port P3 to introduce a secondary pressure regulated by the main governor.

The body 2a, the upper cover 2b, and the lower cover 2c are fastened to each other with bolts 19, and the upper diaphragm 3 and the lower diaphragm 4 are arranged inside the casing 2 with a vertical gap.

The upper diaphragm 3 and the lower diaphragm 4 have the same structure and are incorporated in opposite positions, and the inner diameter side is reinforced by the diaphragm plates 3a and 4a, respectively.

The outer peripheral portion of the upper diaphragm 3 is sandwiched between the body 2a and the upper cover 2b of the casing 2 and held in a fixed position, and the inner peripheral side is fixed to the holder 5.

The outer peripheral portion of the lower diaphragm 4 is sandwiched between the body 2a and the lower cover 2c of the casing 2 and held in place, and the inner peripheral side is fixed to the adjusting ring 14.

The holder 5 has a structure in which an upper support plate 5a and a lower support plate 5b arranged in parallel are connected via a plurality of bridges 5c.

A cylindrical boss portion 5d projecting upward is provided at the center of the upper support plate 5a, and the boss portion 5d is passed through a hole in the center of the upper diaphragm 3 and inserted into the secondary compression chamber 7. A set nut 17 is screwed around the outer periphery of the insertion portion to fix the inner diameter side of the upper diaphragm 3 to the holder 5.

A boss portion 5e projecting downward is provided at the center of the lower support plate 5b, and the boss portion 5e is provided with a screw hole 5f opened on the end surface (lower surface) of the boss portion.

The supply valve 10 is a combination of a nozzle 10a for fixing the position of an upward opening for introducing a primary pressure into the drive pressure chamber 6 and a seat packing 10b for contacting and separating from the nozzle.

The nozzle 10a causes the primary pressure introduced through the introduction passage 9 to flow into the drive pressure chamber 6. The seat packing 10b is connected to the inside of the upper support plate 5a of the holder 5 (boss portion 5d and its boss portion 5d) connected to the exhaust valve 11 (rod valve) and attached to the upper diaphragm 3 together with the exhaust valve 11. It is incorporated in the hollow disk (inside 5 g).

The exhaust valve 11 is urged in the valve closing direction by the spring 11a.

The pressure adjusting mechanism 13 changes the pressure adjustment value of the secondary pressure by the main governor by increasing or decreasing the urging force applied to the diaphragm by the spring 12, and includes a spring receiver 13a attached to the lower surface of the diaphragm plate 4a. It is composed of a spring retainer 13b that receives the lower end of the spring 12 and a pressure adjusting bolt 13c (that in the figure has a handle) screwed into a cap 2d that propels the spring retainer 13b.

The adjusting ring 14 is provided below the holder 5. As shown in FIGS. 3 and 4, the adjusting ring 14 is configured as a large diameter portion 14a arranged in the drive pressure chamber 6 on the upper side and a small diameter portion 14b facing the atmospheric pressure chamber 8 on the lower side. A recess 14c is provided in the center of the upper surface of the holder 5 to receive the boss portion 5e provided on the lower support plate 5b of the holder 5 so as to be slidable in the axial direction.

The boss portion 5e and the recess 14c are slidably fitted to each other, and the holder 5 and the adjusting ring 14 are positioned with each other by the boss portion 5e and the recess 14c, and the axial movement of each other is guided. Will be done.

The small diameter portion 14b of the adjusting ring 14 is passed through a hole in the center of the lower diaphragm 4, and inside the atmospheric pressure chamber 8, a set nut 18 is screwed into the small diameter portion 14b to adjust the inner diameter side of the lower diaphragm 4. It is fixed at 14.

The adjusting screw 15 is attached to the adjusting ring 14 so as to be rotatable and non-movable in the axial direction. Then, the male screw portion 15a on the upper portion of the adjusting screw 15 is screwed into the screw hole 5f provided in the boss portion 5e of the holder 5.

The adjusting screw 15 has a rotation operation unit 15b at the lower end thereof, and the lower end side having the rotation operation unit 15b is arranged in the atmospheric pressure chamber 8.

The illustrated rotation operation unit 15b facing the atmospheric pressure chamber 8 is a square hole for engaging a square wrench, but a square shaft for externally fitting a socket of a socket wrench and various drivers (plus driver, minus driver, Torx) It is possible to replace it with a slit or engaging recess for engaging (registered trademark) driver, etc.).

The adjusting screw 15 is held in the adjusted position by the lock nut 16 screwed on the outer circumference. The adjusting screw 15 can be set so that the receiving state of the boss portion 5e is maintained by the concave portion 14c of the adjusting ring at the position where the adjusting screw 15 is removed from the boss portion 5e of the holder 5. Even if the adjusting screw 15 may come out of the screw hole 5f due to excessive operation, the adjusting screw 15 can be easily re-screwed into the screw hole 5f.

In the supply valve 10, when the forces applied to the upper and lower diaphragms 3 and 4 are balanced, the valve portion has an opening degree of 0 (this is a state in which the outlet of the nozzle 10a is blocked by the seat packing 10b). Alternatively, a constant opening (a state in which the seat packing 10b is separated from the nozzle 10a by a certain amount) is maintained.

When the secondary pressure introduced into the secondary pressure chamber 7 drops from this state, the upper and lower diaphragms 3 and 4 are pushed to the secondary pressure chamber 7 side together with the holder 5 by the force of the spring 12, and the supply is supplied. The valve portion opening of the valve 10 becomes large.

Therefore, the amount of primary pressure introduced into the drive pressure chamber 6 increases, the pressure in the drive pressure chamber 6 increases, and the force pushing the lower diaphragm 4 toward the atmospheric pressure chamber 8 increases.

As a result, the upper and lower diaphragms 3 and 4 move downward along with the holder 5, and are returned to the balance point of the forces applied against both of them, so that the valve portion opening degree of the supply valve 10 becomes smaller.

Since the operation of the main governor due to the increase / decrease in the valve opening of the pilot governor has already been described, the re-explanation here is omitted.

The pilot governor 1 shown in FIG. 1 corrects the deviation of the response characteristic value due to the individual difference as follows.

First of all, the response characteristic value confirmed in advance by the inspection is used as the reference characteristic value, and the response before correction to the decrease in the secondary pressure with the secondary pressure chamber of the pilot governor to be inspected filled with the gas of the predetermined pressure. Inspect the characteristics.

After that, the response characteristic value obtained in the inspection is compared with the reference characteristic value to calculate the screwing amount of the adjusting screw 15 with respect to the screw hole 5f of the holder 5.

The relationship between the screwing amount of the adjusting screw 15 with respect to the screw hole 5f and the relative position of the upper and lower diaphragms 3 and 4 can be known from the inspection data of the pilot governor of the same specifications carried out in advance, and if the inspection data is available, the response characteristics. It is possible to calculate the amount of screwing into the screw hole 5f of the adjusting screw 15 required for the correction.

Once the amount of screwing of the adjusting screw 15 required to correct the response characteristics is obtained, remove the cap 2d together with the pressure adjusting bolt 13c screwed into the cap 2d, and remove the spring retainer 13b and the spring 12 from the atmospheric pressure chamber 8. ..

Then, a tool for rotation operation (not shown) is inserted into the atmospheric pressure chamber 8, and the adjusting screw 15 is rotated by a required amount with the tool, and the position of the adjusting ring 14 with respect to the holder 5 (within the radial direction of the lower diaphragm 4). The mounting position on the end side) is changed from the position shown in FIG. 5 to the position shown in FIG.

At this time, the upper diaphragm 3 is held in the original position as shown in FIGS. 7 and 8, and the valve portion opening d of the supply valve 10 does not change.

After the above adjustment is completed, the locknut 16 is tightened, the spring retainer 13b and the spring 12 are returned to their original positions, and the cap 2d is attached.

After that, re-examination is performed to confirm whether the adjusted response characteristics are appropriate. At this time, since the secondary pressure chamber 7 is filled with the pressurized gas having the pressure required for the inspection, the refilling operation of the gas for the re-inspection is not required as in the conventional product.

Further, the adjustment of the positional relationship between the upper and lower diaphragms 3 and 4 by the rotation operation of the adjusting screw 15 is performed by moving only the lower diaphragm 4 by the rotation operation of the adjusting screw 15, so that the response to the fluctuation of the screwing amount of the adjusting screw 15 is performed. The change width of the characteristics is small unlike the conventional products in which the upper and lower diaphragms 3 and 4 move at the same time during adjustment. Therefore, the response characteristics can be finely adjusted, and the fine adjustment work becomes easy.

It should be noted that the above description of the vertical relationship between the diaphragm, the support plate of the holder, and the cover of the body is for convenience of explanation, and the pilot governor of the present invention can also be used in an inverted state.

1 Pilot governor 2 Casing 2a Body 2b Upper cover 2c Lower cover 2d Cap P1 to P3 Port 3 Upper diaphragm 4 Lower diaphragm 3a, 4a Diaphragm plate 5 Holder 5a Upper support plate 5b Lower support plate 5c Bridge 5d, 5e Boss 5f Screw hole 5g Hollow disk 6 Drive pressure chamber 7 Secondary pressure chamber 8 Atmospheric pressure chamber 9 Introduction passage 10 Supply valve 10a Nozzle 10b Seat packing d Valve opening 11 Exhaust valve 11a Spring 12 Spring 13 Pressure adjustment mechanism 13a Spring receiver 13b Spring retainer 13c Pressure adjustment bolt 14 Adjustment ring 14a Large diameter part 14b Small diameter part 14c Recession 15 Adjustment screw 15a Male thread part 15b Rotation operation part 16 Lock nut 17, 18 Set nut 19 Fastening bolt 21 Primary side pipeline 22 Secondary side pipeline 23 Main governor 23a On-off valve 23b Balance pressure chamber 23c Loading pressure chamber 23d Main spring 24 orifice

Claims (5)

A casing (2) having a drive pressure chamber (6) for introducing a primary pressure, a secondary pressure chamber (7) for introducing a secondary pressure regulated by a main governor, and an atmospheric pressure chamber (8) inside.
An upper diaphragm (3) and a lower diaphragm (4) arranged vertically at intervals inside the casing (2) with the drive pressure chamber (6) in between.
A holder (5) connecting the upper diaphragm (3) and the lower diaphragm (4),
A supply valve (10) in which a nozzle (10a) for fixing the position of an upward opening for introducing a primary pressure into the drive pressure chamber (6) and a seat packing (10b) for contacting and separating from the nozzle (10a) are combined. ,
An exhaust valve (11) provided in the upper diaphragm (3) and interlocking with the supply valve (10) to communicate the drive pressure chamber (6) with the secondary pressure chamber (7).
An attachment that is installed inside the atmospheric pressure chamber (8) and urges the upper diaphragm (3) and the lower diaphragm (4) together with the holder (5) toward the secondary pressure chamber side (7). It has a spring (12) that can adjust the atmospheric pressure,
When the pressure in the secondary pressure chamber (7) drops, the seat packing (10b) follows the displacement of the upper diaphragm (3) and the lower diaphragm (4), and the valve portion opening of the supply valve (10) increases. In this situation, the pilot governor supplies the pressure introduced into the drive pressure chamber (6) via the nozzle (10a) to the loading pressure chamber of the main governor as a drive pressure.
It has an adjustment mechanism that changes the relative position of the upper diaphragm (3) and the lower diaphragm (4).
The adjustment mechanism has an adjustment ring (14) fixed to the lower diaphragm (4) and a rotation operation unit (15b) facing the atmospheric pressure chamber (8) so that the adjustment ring (14) can rotate. The adjusting screw (15) is provided, and the adjusting screw (15) is screwed into the holder (5).
The inner end side of the lower diaphragm (4) is fixed to the adjusting ring (14), and is attached to the adjusting ring (14) by adjusting the screwing amount of the adjusting screw (15) attached to the holder (5). A pilot governor in which the relationship between the fixed position of the lower diaphragm (4) and the fixed position of the upper diaphragm (3) with respect to the holder (5) changes. The casing (2) includes a lower cover (2c) that covers the atmospheric pressure chamber (8) and a cap (2d) that covers the lower end opening of the lower cover (2c), and the cap (2d) is removable. The pilot governor according to claim 1, wherein the cap (2d) is removed from the lower cover (2c) to rotate the adjusting screw (15). The adjusting mechanism includes a locknut (16) that is screwed into the adjusting screw (15) to fix the adjusting screw (15) to a position where the screwing amount is adjusted, and the locknut (16) is a locknut (16). The pilot governor according to claim 1 or 2, wherein the lower end surface of the adjusting ring (14) can be brought into contact with the atmospheric pressure chamber (8). The holder (5) has a boss portion (5e) protruding downward at the center of the lower end, and the adjustment ring (14) has a recess (14c) that accepts the boss portion (5e) so as to be slidable in the axial direction. The pilot governor according to any one of claims 1 to 3, wherein the screw hole (5f) formed in the boss portion (5e) and the adjusting screw (15) are screwed together. The pilot governor according to claim 4, wherein the adjusting screw (15) is configured to maintain the receiving state of the boss portion (5e) by the recess (14c) at a position where the adjusting screw (15) comes out of the screw hole (5f). ..

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