JPH0723601Y2 - Pilot relay - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a pilot relay used in pneumatic instruments, positioners for control valves, and the like.

[Prior Art] Conventionally, various structures of pilot relays, which are one component of the pneumatic regulator, are known, and one of them having the most advantages in performance is shown in FIG. There is a pilot relay showing. This pilot relay belongs to the bleed type as a model because a part of the supply pressure is constantly discharged to the atmosphere during normal operation. A brief description of this model is as follows: 1 has two diaphragms 2, 3 and a partition wall. 4 to the first to fourth chambers 5, 6, 7, 8
The first chamber 5 is connected to an air supply source (not shown) through an air supply passage 9 and is connected to a nozzle (not shown) in a housing partitioned into two to form an air supply chamber. is doing.

The second chamber 6 forms an output chamber, and communicates with the air supply chamber 5 through a communication hole 10 provided in the partition wall 4,
The output air hole 11 communicates with, for example, a valve operating device (not shown).

Reference numeral 12 is a poppet valve that penetrates the communication hole 10 so as to be able to move forward and backward and controls the opening and closing of the communication hole 10. The valve body 12A is seated on the valve seat of the partition wall 4 from below to close the communication hole 10, and the upper valve body 12B is formed at the upper end of the lower end opening 15a of the exhaust passage 15 formed inside the area plate 14. Correspondingly provided. The exhaust passage 15
The upper end opening portion 15b of the is open to the third chamber 7.

The third chamber 7 forms an exhaust chamber, and has a bleed hole.
16 communicates with the outside of the housing 1.

The fourth chamber 8 forms a back pressure chamber by supplying the nozzle back pressure P _N as an input pressure through the nozzle back pressure hole 17.

The area plate 14 is commonly held by the diaphragms 2 and 3 and is located in the exhaust chamber 7, the nozzle back pressure P _N acts on the upper surface thereof, and the upper end of a bias spring 18 is pressed against the lower surface thereof. The spring pressure of the spring 18 opposes the nozzle back pressure P _N.

In this case, since the spring 13 and the bias spring 18 are effective in the assembled state, the communication hole 10 is closed and the exhaust passage 15
The lower end opening 15a is closed.

When the pilot relay configured as described above is used as a positive operation type in which the output increases as the input increases, the nozzle back pressure flowing from the nozzle back pressure hole 17 into the back pressure chamber 8 is increased.
When P _N increases, the diaphragm 2 is displaced downward, and the area plate 14 descends against the bias spring 18, and the poppet valve 12 also descends against the spring 13. As a result, the lower valve body 12A of the poppet valve 12 is separated from the valve seat of the partition wall 4 to connect the air supply chamber 5 and the output chamber 6,
The supply air pressure P _S from the air supply passage 9 flows into the output chamber 6 through the communication hole 10, and the pressure in the chamber 6 is the drive pressure of the valve.
It is supplied to the operating device as P _O through the output air hole 11.

On the other hand, when the nozzle back pressure P _N is reduced from this state, the bias sprig 18 causes the area plate 14 to return to the upward position, and the poppet valve 12 is moved upward by the elastic force of the spring 13. This time,
The upper valve body 12B of the poppet valve 12 is the lower end opening 1 of the exhaust passage 15.
Since the exhaust chamber 7 and the output chamber 6 are communicated with each other via the passage 15 apart from the exhaust passage 5a, the pressure in the output chamber 6 is set to the exhaust passage 15
And is discharged to the outside of the housing 1.

[Problems to be Solved by the Invention] By the way, in such a conventional pilot relay, a bias spring having a different spring force is used to change the bias pressure to the area plate 14 according to the change of the gain of the controller.
18 were prepared and these were selectively used. However, preparing multiple bias springs 18 not only increases the number of parts, but also complicates parts management.
There is also a risk of losing things that are not used. Furthermore, when changing the bias in the field, it is necessary to wait until a bias spring suitable for the bias arrives, resulting in a loss of time.

Therefore, the present invention has been made in view of the above-mentioned conventional problems, and the purpose thereof is to change the bias pressure without exchanging parts and to reduce the number of parts. To provide a pilot relay.

[Means for Solving the Problems] In order to achieve the above object, the present invention is a pilot relay that supplies a nozzle back pressure as an input pressure and amplifies the nozzle back pressure to obtain an output pressure. Both ends are contacted with each other, a conical bias spring is provided concentrically with the poppet valve, and a seating surface having a height difference according to the large and small ends of the bias spring is provided on one of the spring contact surfaces.

[Operation] In the present invention, the conical bias spring is installed upside down when the bias pressure is changed. The bearing surface having a difference in height locks one end of the bias spring inverted by the different step surface, thereby changing the compression amount of the spring, that is, the bias pressure.

[Embodiment] The present invention will be described in detail below based on an embodiment shown in the drawings.

FIG. 1 is a sectional view showing an embodiment of a pilot relay according to the present invention. In the figure, the same components as those in FIG. 4 are designated by the same reference numerals, and the description thereof will be omitted. In this embodiment, a seating surface 20 composed of two ring-shaped steps 20a and 20b having an appropriate step size D is provided on the lower surface of the area plate 14 against which the upper end of the bias spring 18 is pressed, that is, the spring contact surface 21. The point that the bias spring 18 is formed in a conical shape is different from the conventional device shown in FIG. 4, and the other configurations are the same. The diameter of the step 20a is substantially equal to the diameter of the small diameter end portion 18a of the bias spring 18, and the diameter of the step 20b is substantially equal to the diameter of the large diameter end portion 18b of the bias spring 18. The bias spring 18 is interposed between the seat surface 20 and the spring contact surface 22 of the housing 1 in a compressed state, that is, when assembled in a normal state, the small-diameter end portion 18a causes the small-diameter end portion 18a to reach the step 20a. When pressed together, inverted and assembled, the second
As shown in the figure, the large-diameter end portion 18b is pressed against the step 20b. Therefore, the compression amount of the bias spring 18 is different by D between the normal state and the inverted state, which causes the area plate 14
The bias pressure for is switched in two steps.

In this case, as a matter of course, FIG. 1 shows a high bias state because the compression amount of the bias spring 18 is large, and FIG. 2 shows a low bias state because the compression amount is small.

FIG. 3 is a diagram showing the relationship between the nozzle back pressure P _N and the output pressure P _{O. When} the nozzle back pressure P _N is P ₁ , the bias spring 18 is installed in the normal state shown in FIG. 1 to counter this. When the nozzle back pressure P _N is P ₂ , the nozzle back pressure P _N is installed in an inverted state to counter this.

Thus, in the pyrite relay having such a configuration, the bias pressure can be switched between the two stages by one bias spring 18, so that it is not necessary to prepare two bias springs having different spring pressures, and It has an advantage that the number of parts can be reduced.

In the above embodiment, the seat surface 20 is provided on the spring contact surface 21 of the area plate 14, but the present invention is not limited to this, and the spring of the housing 1 is used instead of the area plate 14. Of course, a similar seating surface may be provided on the contact surface 22.

[Effect of the Invention] As described above, the pilot relay according to the present invention is
The bias spring has a conical shape, and one of the housing and the spring contact surface of the area plate, to which each end of the spring is pressed, has a seat having a height difference depending on the size of the bias spring. Since we have a surface,
The bias pressure can be changed by incorporating the bias spring by turning it upside down, which can reduce the number of parts and facilitate the management of parts.

[Brief description of drawings]

FIG. 1 is a sectional view of a pilot relay according to an embodiment of the present invention in a high bias state, FIG. 2 is a sectional view of a low bias state, and FIG. 3 is a diagram showing a relationship between nozzle back pressure and output pressure. FIG. 4 is a sectional view showing a conventional example of a pilot relay. 1 ... Housing, 2, 3 ... Diaphragm, 6 ... Output chamber, 10 ... Poppet valve, 14 ... Area plate, 18 ... Bias spring, 20 ... Seating surface, 20a, 20b ... Step, 21 ,twenty two
…… Spring contact surface, P _N …… Nozzle back pressure, P _o …… Output pressure.

Claims (1)

[Scope of utility model registration request] 1. A pilot relay that supplies nozzle back pressure as input pressure and amplifies it to output pressure, in which both ends of a housing and an area plate are in contact with the output chamber and a conical bias is concentric with the poppet valve. A pilot relay, characterized in that a spring is provided, and a bearing surface having a height difference according to the large and small ends of the bias spring is provided on one of the spring contact surfaces.