JP2018179213A - Electric valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric valve capable of being used even at a low temperature.SOLUTION: A one-direction electricity is conducted to a solenoid coil 28 in switching a one-side electric valve, and thus even after a plunger 24 is moved to one end side and electrification to the solenoid valve is stopped, the plunger 24 is held at the one end side by a magnet. A reverse-direction electricity is conducted to the solenoid valve 28 in switching the other-side electric valve, and thus even after the plunger 24 is moved to the other end side and electrification to the solenoid valve 28 is stopped, the plunger 24 is held at the other end by a spring 34.SELECTED DRAWING: Figure 1

Description

  TECHNICAL FIELD The present invention relates to a low heat generation electrically operated valve used at low temperature.

  In magnetic measurement devices (SQUIDs), nuclear magnetic resonance imaging devices (MRI), nuclear magnetic resonance spectroscopy devices (NMR), etc., superconducting electromagnets are used for measurement. For this reason, expensive liquid helium is used for cooling. Then, in order to reduce the usage-amount of liquid helium, the circulation utilization system of helium is proposed (refer patent document 1).

  In such a circulation system, it is necessary to arrange various valves in the fluid flow path. In particular, valves provided in the flow paths of liquid helium and low temperature helium gas are required to function stably even at very low temperatures, and are also required to generate less heat.

  A valve using a self holding solenoid is shown in Patent Document 2 and the like.

JP 2005-291629 A JP, 2004-353704, A

  For example, the motorized valve normally energizes the solenoid to maintain either the open or closed state. Therefore, a large amount of heat is given to the low temperature fluid. Therefore, it was difficult to use the motorized valve. Also, materials such as plungers and springs should be able to be used properly at low temperatures.

  The motor-operated valve according to the present invention is composed of a solenoid coil that generates a magnetic field in different directions depending on the current flow direction, and a material with a small change in characteristics as a magnetic body at low temperatures, and is driven by the magnetic field generated by the solenoid coil. A plunger which opens and closes a flow path of an electric valve by movement to one end and movement to the other end, a magnet which draws close to one end of the plunger, and a small change in elastic coefficient at low temperature. A spring is provided to urge the other end side. When switching the motorized valve on one side, the solenoid coil is energized in one direction, thereby moving the plunger to one end side and stopping the energization of the solenoid coil. While holding the plunger on one end side, the other direction to the solenoid coil when switching the motorized valve on the other side After stopping the energization to the energization solenoid coil caused thereby moving the plunger to the other side to hold the plunger at the other end by a spring.

  The spring may be made of inconel.

  The plunger may be made of Permalloy B, Invar, or SUS430.

  Also, the sheet may be made of polyimide or PTFE.

It is a figure which shows the structure (closed state) of the electrically operated valve which concerns on embodiment. It is a figure showing composition (open state) of a electromotive valve concerning an embodiment.

  Hereinafter, embodiments of the present invention will be described based on the drawings. The present invention is not limited to the embodiments described herein.

"Constitution"
1 and 2 show the configuration of the motor-operated valve 1 according to the embodiment, and FIG. 1 shows the motor-operated valve closed state, and FIG. 2 shows the motor-operated valve open state.

  The motor-operated valve 1 has a generally cylindrical valve body 10. Inside the valve body 10, a first flow passage 12 and a second flow passage 14 are formed. The first flow passage 12 has an opening 12a on the outer peripheral surface in the radial direction of the valve body 10, and is directed in the center direction from there and then bent in an axial direction and has an opening 12b on the surface on one end side It is a road. On the other hand, the second flow passage 14 is a flow passage extending in the axial direction, and is a linear flow passage having an opening 14 a on one end side and an opening 14 b on the other end side.

  The open side of the cylindrical container-like housing 20 is attached so as to cover one end side of the valve body 10. That is, one end of the valve body 10 is substantially flat, and the end of the housing 20 is attached to the periphery thereof. The valve body 10 is formed of, for example, stainless steel (SUS316L, SUS304, etc.).

  An annular cylinder 22 is installed on the inner peripheral side of the housing 20 on the valve body 10 side. One end side of the cylinder 22 is in contact with one end side surface of the valve body 10, and by sealing this, a sealed space is formed inside. The openings 12b and 14a of the first and second flow passages 12 and 14 open into the sealed space. The housing 20 and the cylinder 22 are also made of stainless steel similar to the valve body 10.

  A cylindrical plunger 24 is disposed on the inner peripheral side of the cylinder 22 so that the outer peripheral surface thereof is in contact with the inner peripheral surface of the cylinder 22. The plunger 24 is axially movable. A seat 26 is attached to the end face of the plunger 24 on the valve body 10 side. Therefore, the seat 26 is located on the plunger 24 side of the sealed space. The central portion of the seat 26 is convex in a chevron shape, while the opening 14a of the second flow passage 14 of the valve body 10 is tapered in the periphery and has a shape in which the both coincide with each other. . Therefore, in a state where the plunger 24 is pressed against the valve body 10, the second flow path 14 is closed and the electric valve 1 is closed. The plunger 24 is preferably made of Permalloy B or Invar, which is a magnetic body. These materials are ferromagnetic materials and are small in conversion of characteristics as a magnetic material even at low temperatures, and thus are suitable for an apparatus used at low temperatures as in this embodiment. In addition, steel materials such as SUS430 and SUM23 can also be used. The sheet 26 is made of, for example, PTFE (polytetrafluoroethylene), polyimide or the like. Polyimide is less likely to change its characteristics even at low temperatures, can maintain its deformation characteristics, and is particularly suitable as the sheet 26 as a sealing material.

  A cylindrical solenoid coil 28 is disposed rearward of the cylinder 22 (opposite to the valve body 10). The rear side of the plunger 24 extends rearward from the rear end of the cylinder 22 and is located inside the solenoid coil 28 at a predetermined interval.

  Behind the plunger 24, a cylindrical base core 30 of a magnetic material is disposed. Base core 30 may be constructed of the same material as plunger 24. A disc or annular magnet (permanent magnet) 32 is disposed behind the base core 30 and the solenoid coil 28. The base core 30 and the magnet 32 are fixed to the housing 20. The magnet 32 is formed of, for example, neodymium. A cylindrical recess is formed on the rear side of the plunger 24, and a spring 34 is disposed between the front end of the recess and the front end of the base core 30. The spring 34 is a compression spring and biases the plunger 24 forward. The spring 34 is formed of, for example, Inconel (Inconel 750 or the like). Inconel has a sufficient elasticity as a spring material and has a small change in elastic coefficient even at low temperatures, so it is particularly suitable as a spring 34 as a biasing member of the plunger 24 in this embodiment.

"Action"
First, in the state of FIG. 1, that is, in the closed state of the electric valve 1, the plunger 24 and the seat 26 are pressed against the valve body 10 by the biasing force of the spring 34. Accordingly, the flow of fluid between the first flow passage 12 and the second flow passage 14 is stopped. Although the plunger 24 is drawn toward the magnet 32 by the magnetic force of the magnet 32, the biasing force of the spring 34 is set larger, so the plunger 24 is stable in a state of being pressed against the valve body 10. .

  Here, a current in one direction is supplied to the solenoid coil 28 (one-direction current flow direction), and the solenoid coil 28 generates a suction force in the same direction as the magnet 32 on the plunger 24. As a result, magnetic lines of force pass through the plunger 24 and the base core 30, and the plunger 24 receives a rearward force in combination with the magnetic force of the magnet 32. This force is greater than the biasing force of the spring 34 so that the plunger 24 moves rearward and catches on the base core 30. That is, the front end surface of the base core 30 and the rear end surface of the plunger 24 are flat in the direction perpendicular to the axis, and both contact as a whole. And, since the attraction force by the magnetic force is in inverse proportion to the square of the distance, the attraction force when the distance to the base core 30 becomes zero is large, and even after the current to the solenoid coil 28 is cut off, the attraction force is The force is greater than the biasing force of the spring 34. Therefore, as shown in FIG. 2, the attraction force of the magnet 32 stably holds the plunger 24 in the state of being positioned on the rear side. That is, in a state in which no current flows to the solenoid coil 28, the electric valve 1 is maintained in the open state.

  Next, current is applied to the solenoid coil 28 in the direction opposite to the above one direction (the current supply direction is reversed). As a result, magnetic lines of force pass through the base core 30 and the plunger 24 to generate a magnetic field in the direction to cancel the magnetic force from the magnet 32 with respect to the plunger 24. By this, the biasing force of the spring 34 becomes larger than the magnetic force from the magnet 32, thereby returning to the state of FIG.

  As described above, according to the present embodiment, when the electric valve 1 is switched between the closed state and the open state, the electric valve 1 can be switched between open and closed by supplying a current in a predetermined direction to the solenoid coil 28. Therefore, the energization time is short, and it is possible to suppress the influence of the heat generated by the energization of the solenoid coil 28 on the motor-operated valve 1.

<Specific example>
For example, the plunger 24 having an outer diameter of about 20 mmφ is used, and the power when the solenoid coil 28 is energized is about 65 W. Assuming that the actuation stroke is 1 mm, the biasing force of the spring 34 is 60 N when the valve is open, 40 N when the valve is closed, and the suction force by the magnet 32 is set so that the valve thrust when the valve is closed is 30 N or more.

By such setting, the leak of helium gas when the valve was closed could be reduced to 1 × 10 ⁻¹⁰ Pa · m ³ / sec or less.

<Other configuration>
A seal material such as a metal ring is preferably disposed at the contact portion between the valve body 10 and the cylinder 22 for sealing. Although a mechanical seal or the like may be disposed between the inner peripheral surface of the cylinder 22 and the outer peripheral surface of the plunger 24, it is preferable to make the inside of the housing 20 airtight as a whole.

By forming the sheet 26 with a polyimide, a suitable sealing characteristic that can make the leak of helium gas 1 × 10 ⁻¹⁰ Pa · m ³ / sec or less can be obtained even at a low temperature such as 4K.

  Further, by using the spring 34 as an inconel coil spring, the spring force can be maintained even at a low temperature such as 4 K, and the durability of 100,000 times or more can be obtained.

  By configuring the plunger 24 with Permalloy B or Invar, it operates suitably even at a low temperature such as 4K.

  A base core 30 of a magnetic material is disposed inside the solenoid coil 28, and the magnetic force of the magnet 32 is applied to the plunger 24 via the base core 30 which receives the magnetic field of the solenoid coil 28 largely. You can move smoothly. Moreover, the bad influence to the magnet 32 can be suppressed.

  Either of the first flow passage 12 and the second flow passage 14 may be an inflow passage or an outflow passage. The second flow passage 14 is preferably positioned at the center of the recess with respect to the opening 14 a as an axial flow passage and closed by a protrusion provided at the center of the sheet 26, but the unevenness may be reversed. Moreover, although it was set as the structure which can obstruct | occlude the opening 12b of the 1st flow path 12 by the sheet | seat 26 in this embodiment, the opening 12b may not necessarily be able to be obstruct | occluded by the sheet | seat 26. FIG.

  The electric valve 1 according to the present embodiment may have an energization time in a range of several msec to several sec, and in particular, may be energized only at the time of switching, so that the calorific value is small. It can be used suitably.

1 motorized valve, 10 valve body, 12 first flow passage, 14 second flow passage, 20 housing, 22 cylinder, 24 plunger, 26 seat, 28 solenoid coil, 30 base core, 32 magnet, 34 spring.

Claims (4)

A solenoid coil that generates a magnetic field in different directions depending on the direction of energization;
A plunger which is made of a material having a small change in characteristics as a magnetic body at a low temperature, and is driven by a magnetic field generated by a solenoid coil, the flow of the electric valve by movement to one end and movement to the other A plunger for opening and closing the passage,
A magnet that pulls toward one end of the plunger;
A spring that biases the plunger to the other end with a small change in the modulus of elasticity at low temperatures;
Including
When switching the motor valve on one side, the solenoid coil is energized in one direction, thereby moving the plunger to one end side and stopping the energization of the solenoid coil so that the magnet is held by the magnet on one end side and the other side At the time of switching the valve, the solenoid coil is energized in the other direction, thereby moving the plunger to the other end side and holding the plunger on the other end side by the spring even after the energization of the solenoid coil is stopped.
Motorized valve. The electric valve according to claim 1, wherein
The spring is constituted by Inconel,
Motorized valve. It is an electrically operated valve of Claim 1 or 2, Comprising:
The plunger is made of Permalloy B, Invar, or SUS430,
Motorized valve. It is an electrically operated valve as described in any one of Claims 1-3,
The sheet is made of polyimide or PTFE,
Motorized valve.

Images