JPH0217713B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a low-temperature fluid pump that pumps low-temperature fluid to a low-temperature device such as a superconducting electromagnet. For fluid pumps, by slowly moving the piston rod up and down, the durability of the bellows is significantly extended, and by applying a constant pressure to the oil cylinder, the fluid discharge from the pump is constant, and the piston rod's top dead center and bottom dead center are fixed. Instantly switches the vertical movement at a point, making the pulsation of fluid discharge from the pump extremely small, and also controls the vertical movement speed and vertical range of the piston rod by adjusting the amount of oil sent into the cylinder. This invention relates to a low-temperature fluid pump such as liquid helium, in which the discharge flow rate of low-temperature fluid can be easily adjusted by incorporating a suction and discharge valve inside the pump, and the pump is lightweight and compact, and a method of operating the same. .

(Prior art) Conventional low-temperature fluid pumps include piston pumps that use low-temperature seals, but this generates a large amount of heat due to friction in its sliding parts, and low-temperature fluids with low latent heat of vaporization suffer significant losses due to this heat generation. This results in a pump with a large amount of heat, making it unsuitable as a pump for low-temperature fluids.

In order to solve this problem, there is a reciprocating pump using bellows, but the suction and discharge valves are located outside the pump and the shape is not integrated, making it unsuitable for miniaturization.

Further, when a reciprocating pump is operated by driving an electric motor using a crank or the like, its vertical movement speed becomes sinusoidal with respect to time, and the discharge flow rate of the fluid is not constant and large pulsations occur.

As described above, when a conventional pump is used as a low-temperature fluid pump, there are problems in that it generates heat, cannot be made lightweight and compact, and also causes pulsations in the discharge flow rate.

(Problems to be Solved by the Invention) The present application addresses the problems that in conventional fluid pumps, low-temperature fluids with low latent heat of vaporization evaporate due to heat generation, resulting in pumps with large losses; This invention attempts to solve the problem of flow pulsation.

(Means for Solving the Problems) The present invention, as a means for solving the above-mentioned problems, includes a vertically movable vertically movable internal cylinder via a slider in which a vertically sliding cylinder is locally interposed within a fixed cylinder. A partition plate that divides the sliding tube into upper and lower halves is fixed to the fixed tube through a long hole formed in the vertical direction of the body of the upper and lower sliding tubes, and a valve holding tube with holes is installed at the upper and lower portions of the upper and lower sliding tubes. A pair of ventilation cylinders equipped with a communication hole communicating with this hole are fixed facing each other, and a pair of bellows cylinders are used to airtightly connect the upper and lower parts of the vertical sliding cylinders and the middle partition plate. A pair of pump chambers with variable volume are provided above and below, surrounded by the partition plate, a ventilation tube of the vertical sliding tube, and a bellows tube, and each of the pair of ventilation tubes has a relative depressurization of the corresponding pump chamber. A normally-closed suction valve is provided which opens with Discharge holes are provided, and each pair of discharge holes is provided with a normally closed discharge valve that opens when the relative pressure of the corresponding pump chamber is increased.Furthermore, a rod connected to the piston of the hydraulic cylinder is provided at the top of the vertical sliding tube. A cryogenic fluid pump such as helium is connected to the fluid helium.

In addition, the vertical sliding tube is internally movable up and down via a slider that is locally interposed in the fixed tube, and a partition plate that divides the vertical sliding tube into upper and lower halves is installed in the vertical direction of the body of the upper and lower sliding tube. A valve holding cylinder with a hole and a pair of ventilation cylinders each having a communication hole communicating with the hole are fixed to the upper and lower parts of the vertical sliding cylinder facing each other. At the same time, the upper and lower parts of the vertical sliding tube and the middle partition plate are airtightly connected by a pair of bellows tubes, and the ventilation tube and bellows tube between the middle partition plate and the vertical sliding tube are connected above and below the middle partition plate. A pair of pump chambers with a variable volume surrounded by is provided with a delivery hole for discharging the low-temperature fluid to the outside, and is provided with a pair of discharge holes that communicate with the delivery hole from opposing pump chambers on both left and right sides of the A cryogenic fluid pump equipped with a normally closed discharge valve that opens when the pressure is increased is used, and the vertical sliding cylinder of this cryogenic fluid pump is moved up and down by a piston rod of a hydraulic cylinder, based on a signal from a cryogenic fluid pump control device. Air is selectively sent to a pair of air-oil converters through actuated switching valves, and the hydraulic cylinders are actuated by the working oil of the air-oil converters, and the temperature is lowered by a signal from a differential transformer that detects the working distance of the hydraulic cylinders. The switching valve can be switched and controlled via a fluid pump control device.

(Function) A differential transformer is provided that is activated by the vertical movement of the piston of the hydraulic cylinder, and a signal from the differential transformer causes the cryogenic fluid pump control device to control the switching valve and send switching air to the oil converter. When the rod is lowered, the upper As the bellows tube contracts, the upper suction valve closes due to the pressure of the low temperature fluid in the bellows tube, and the discharge valve on the right side of the partition plate opens due to the pressure of the low temperature fluid in the upper bellows tube, resulting in the discharge process. The low-temperature fluid inside is sent out from the discharge hole on the right side to the required location through the communication hole and the delivery hole.

On the other hand, the lower suction valve opens because pressure is applied upward by the low-temperature fluid in the lower suction chamber, and the discharge valve on the left side of the partition plate is closed by the spring as the bellows tube extends and the inside of the bellows tube becomes depressurized. The low-temperature fluid is sucked into the lower bellows cylinder from the lower suction chamber through the hole, the circular recess and the circulation hole.

When the rod is raised, pressure is applied downward by the low temperature fluid in the upper suction chamber, so the upper suction valve opens.
The discharge valve on the right side of the partition plate is closed by a spring as the bellows tube extends and the pressure inside the bellows tube is reduced, resulting in the suction process, and the low-temperature fluid is sucked into the upper bellows tube from the upper suction chamber.

On the other hand, as the lower bellows tube contracts, the lower bellows suction valve closes due to the pressure of the low temperature fluid inside the bellows tube, and the discharge valve on the left side opens due to the pressure of the low temperature fluid inside the lower bellows tube, resulting in a discharge process. The low-temperature fluid is sent out from the discharge hole on the left side to the required location through the communication hole and the delivery hole.

(Example) A rod 3 of a hydraulic cylinder 2 is connected to a low temperature fluid pump 1, a piston 4 attached to the upper end of the rod 3 is inserted in the middle of the hydraulic cylinder 2, and oil adjustment is carried out at the upper and lower ends of the hydraulic cylinder 2. The oil pipes 6, 6' are connected and opened through the valves 5, 5', and the other end of each oil pipe 6, 6' is connected to the lower end of the air oil converter 7, 7'. Air pipes 8, 8' are connected and opened at the upper ends of the air pipes 8, 8', and the other ends of the air pipes 8, 8' are connected to a switching valve 9.

The switching valve 9 is electrically connected to the low temperature fluid pump control device 10 and is provided with a differential transformer 11 that is activated by the vertical movement of the piston 4 of the hydraulic cylinder 2. controls the switching valve 9 to send switching air to the air-oil converter 7 or 7',
By sending oil to either the top or bottom of the piston 4 of the hydraulic cylinder 2, the rod 3 can be moved up and down, and the vertical movement of the rod 3 activates the low temperature fluid pump 1 to pump low temperature fluid such as liquid helium to the heat exchanger 12. It is designed so that it can be supplied to the target equipment through.

Next, to explain the cryogenic fluid pump 1, the fixed cylinder 2
1, a vertically sliding cylinder 22 is vertically slidably inserted therein,
A middle partition plate 23 is installed horizontally between the upper and lower sliding tubes 22.
, and attach the inner partition plate 23 to the fixed cylinder 21 with bolts 2.
Fix it at 1'.

However, a long hole 22' is bored in the vertical sliding cylinder 22 at the location of the bolt 21' that fixes the fixed cylinder 21 and the partition plate 23, so that the bolt 21' does not get in the way when the vertical sliding cylinder 22 moves up and down. Do it like this.

A feed hole 2 is provided in the horizontal direction at one location of the partition plate 23.
4, and a recess 26 for operating the discharge valve 25 is formed on the left and right sides of the delivery hole 24 from opposite directions toward the center.
The operating recess 26, the delivery hole 24, and the communication hole 26' communicate with each other.

A discharge valve 25 is placed inside the operating recess 26 via a spring 27, and a valve holding plate 28 having a discharge hole 28' bored in the center from the opening side of the operating recess 26 is attached.

A mounting support plate 29 is fixed to the upper and lower ends of the vertical sliding tube 22, and a metal mesh 3 is placed inside the mounting support plate 29.
0, and then polymerize the valve holder cylinder 32 with a hole 31 in the center inside thereof, and then form the hole 3 of the valve holder cylinder 32.
A suction valve 3 large enough to seal the hole 31 inside the suction valve 1.
3 is polymerized and a partition wall 3 is formed on the outside of the valve retainer cylinder 32.
5a, a recess 34 is provided in the center of the partition wall 35a in which the suction valve 33 can move up and down, and a spring 36 is installed between the suction valve 33 and the recess 34, so that the suction valve 33 is inserted into the hole. 31 are polymerized so as to be always closed, and a ventilation cylinder 35, a valve holding cylinder 32, and a mesh 30 are formed.
And the mounting support plate 29 is fixed together with bolts 37 at the ends, one end of the bellows tube 38 is airtightly attached to the outer peripheral inner surface of the ventilation tube 35, and the other end of the bellows tube 38 is airtightly attached to the partition plate 23. Ventilation cylinder 35 and bellows cylinder 3
8 and the partition plate 23 form a pump chamber 48 whose volume can be changed by the bellows tube 38.

39 is a communication hole provided in the mounting support plate 29; 40
is a suction chamber formed largely in the center of the valve retainer cylinder 32;
Reference numeral 41 designates an annular recess formed on the inner surface of the valve holding cylinder 32 and the outer periphery of the hole 31, and reference numeral 42 represents a communication hole that communicates the annular recess 41 with the inside of the communication cylinder 35.

43 is a bolt for attaching the support plate 29 and the vertical sliding tube 22; 44 is a long hole drilled in the fixed tube 21 so as not to interfere with the vertical movement of the sliding tube 22;
Reference numeral 5 denotes a slider for supporting the fixed tube 21 inserted through the gap between the sliding tube 22 and the fixed tube 21 without wobbling, and is fitted into a hole 46 formed in the fixed tube 21 and is pressed from the outside. It is held down by a member 47 in a detachable manner.

Fixed cylinder 2 of the cryogenic fluid pump formed in this way
1 is inserted into a low-temperature fluid tank (not shown) and fixed airtightly, the mounting support plate 29 on the upper part of the vertical sliding tube 22 is appropriately connected to the lower end of the rod 3 of the hydraulic cylinder 2, and the low-temperature fluid This prevents water from leaking out of the cryogenic fluid tank.

With the above structure, when the vertical sliding cylinder 22 is moved up and down by the vertical movement of the rod 3, the following action is performed.

The cryogenic fluid pump control device 10 controls and switches the switching valve 9 based on a signal from the differential transformer 11 activated by the vertical movement of the piston 4 of the hydraulic cylinder 2, and transfers the air to the air-oil converter 7,
7'.

If the rod 3 is lowered, the upper bellows tube 38 will contract, so the pressure of the low temperature fluid in the upper bellows tube 38 will close the upper suction valve 33 and the discharge valve 25 on the right side of the middle partition plate 23 will close. The pressure of the low-temperature fluid causes the discharge process, and the low-temperature fluid in the bellows tube 38 at the top flows from the discharge hole 28' on the right side to the communication hole 2.
6', and is sent out to the required location through the delivery hole 24. On the other hand, the lower suction valve 33 is connected to the lower suction chamber 4.
The discharge valve 25 on the left side of the partition plate 23 opens because pressure is applied upward by the low-temperature fluid at 0.0, and the lower bellows tube 38 extends and the chamber 48 formed by the lower bellows tube 38 etc. becomes depressurized, so the discharge valve 25 opens with the spring 27. As a result, the suction process is closed and the low temperature fluid is sucked from the lower suction chamber 40 through the hole 31, the annular recess 41 and the communication hole 42 into the bellows tube 38 at the lower part. When the rod 3 is raised, pressure is applied downward by the low temperature fluid in the upper suction chamber 40, so the upper suction valve 33 opens, and the discharge valve 25 on the right side of the partition plate 23 has an upper bellows tube 38 extended. Since the pressure inside the chamber 48 formed by 38 and the like is reduced, the spring 27 closes the chamber 48 to initiate the suction process, and the low-temperature fluid flows into the upper suction chamber 40.
It passes through the hole 31, the annular recess 41, and the communication hole 42, and is sucked into the bellows tube 38 at the top.

On the other hand, since the lower bellows tube 38 contracts, the lower suction valve 33 closes due to the pressure of the low temperature fluid in the lower bellows tube 38, and the left discharge valve 25 opens due to the pressure of the low temperature fluid in the lower bellows tube 38. During the discharge process, the low-temperature fluid in the bellows tube 38 at the bottom flows through the discharge hole 2 on the left side.
8', passes through the communication hole 26' and the delivery hole 24, and is delivered to the required location.

(Effects) The present invention can be miniaturized and extremely simple by incorporating a discharge valve and a suction valve.

(b) Since the rod is operated by converting air into oil, the pump can be used at a relatively low reciprocating speed, which greatly improves the durability of the bellows cylinder and is economical.

c When replacing, by removing the bolts, the vertical sliding tube can be easily removed from the fixed tube from the outside and pulled out to the bottom, making repairs and inspections easy.

d The bellows-type pump has a structure in which only the slider part slides, and there are very few sliding parts, resulting in a low-temperature fluid pump that generates extremely little heat, eliminating the evaporation of low-temperature fluids with low latent heat of vaporization, resulting in high-efficiency low-temperature fluids. It could be a pump.

e By performing the reciprocating motion of the pump with a hydraulic cylinder, the speed of the reciprocating motion is constant, and the pulsation when discharging the fluid is only at the top dead center and bottom dead center of the reciprocating motion, and the top dead center and bottom dead center are also passed instantly. Its pulsation also became extremely small.

f The driving force of the pump is determined by the hydraulic pressure, so determining the hydraulic pressure value also determines the discharge pressure, making operation easier.

g The discharge amount can be determined by the reciprocating stroke and reciprocating speed of the hydraulic cylinder, and the stroke can be changed immediately by feeding back the signal from the differential transformer to the cryogenic fluid pump controller, and the speed can be determined by the reciprocating stroke and reciprocating speed of the hydraulic cylinder. can be changed immediately by changing the pressure on the

[Brief explanation of drawings]

Figure 1 is the cryogenic fluid pump control diagram, Figure 2
The figure is a sectional view of the cryogenic fluid pump, and FIG. 3 is a characteristic diagram of the cryogenic fluid pump. 1...Cryogenic fluid pump, 2...Hydraulic cylinder,
3...Rod, 4...Piston, 7,7'...Air-oil converter, 9...Switching valve, 10...
...Cryogenic fluid pump control device, 11...Differential transformer, 21...Fixed tube, 22...Vertical sliding tube, 2
2'...long hole, 23...inner partition plate, 24...discharge hole, 25...discharge valve, 28'...discharge hole, 3
1...hole, 32...valve holder, 33...suction valve,
35... Ventilation tube, 38... Bellows tube, 42... Distribution hole, 45... Slider, 48... Pump chamber.

Claims (1)

[Scope of Claims] 1. A vertical sliding cylinder is installed inside a fixed cylinder so that it can move up and down via a slider that is locally interposed, and a partition plate that divides the vertical sliding cylinder into upper and lower halves is attached to the upper and lower sliding cylinder. It is fixed to a fixed cylinder through a long hole formed in the vertical direction of the body of the cylinder, and a pair of ventilation cylinders each having a valve holding cylinder with a hole and a communication hole communicating with this hole are installed at the upper and lower parts of the vertical sliding cylinder. The upper and lower parts of the upper and lower sliding tubes and the middle partition plate are fixed facing each other, and the upper and lower parts of the upper and lower sliding tubes are airtightly connected by a pair of bellows tubes. A pair of pump chambers with variable volume surrounded by cylinders are provided, each of the pair of ventilation tubes is provided with a normally closed suction valve that opens by relative depressurization of the corresponding pump chamber, and the inner partition plate is A delivery hole for discharging the low-temperature fluid to the outside is provided inside, and a pair of delivery holes are provided on both the left and right sides of which the pump chambers facing each other communicate with the delivery hole. 1. A low-temperature fluid pump such as helium, which is equipped with a normally closed discharge valve that opens when pressure is increased, and is further connected to a rod connected to a piston of a hydraulic cylinder at the top of a vertical sliding cylinder. 2 A vertical sliding tube is internally movable up and down via a slider that is locally interposed in a fixed tube, and a partition plate that divides the vertical sliding tube into upper and lower halves is installed in the vertical direction of the body of the upper and lower sliding tube. It is fixed to the fixed cylinder through the formed elongated hole, and a pair of ventilation cylinders each having a valve holding cylinder with a hole and a communication hole communicating with this hole are fixed oppositely to the upper and lower parts of the vertical sliding cylinder. The upper and lower parts of the sliding tube and the middle partition plate are airtightly connected by a pair of bellows tubes, and are surrounded by the middle partition plate and the ventilation tube and bellows tube of the upper and lower sliding tubes above and below the middle partition plate. A pair of pump chambers with a variable volume are provided, each of the pair of ventilation pipes is provided with a normally closed suction valve that opens by relative depressurization of the corresponding pump chamber, and a low temperature is provided inside the partition plate. A delivery hole for discharging the fluid to the outside is provided, and a pair of delivery holes are provided on both left and right sides of the delivery hole that communicate with the delivery hole from opposing pump chambers. A switching valve operates based on a signal from a cryogenic fluid pump control device by using a cryogenic fluid pump equipped with a normally closed discharge valve that opens when the cryogenic fluid pump is opened, and by moving the vertical sliding cylinder of the cryogenic fluid pump up and down with a piston rod of a hydraulic cylinder. The air is selectively sent to a pair of air-oil converters through the air-oil converter, and the hydraulic cylinder is actuated by the working oil of the air-oil converter, and the cryogenic fluid pump control device is controlled by a signal from a differential transformer that detects the working distance of the hydraulic cylinder. A method of operating a low temperature fluid pump such as liquid helium, characterized in that a switching valve is switched and controlled via.