JPH05231302A - Piston pump - Google Patents

Abstract

PURPOSE:To provide a piston pump which is of a small type and free from vibration and noise generation. CONSTITUTION:A bellows 21 is provided on a part of a piston 6 in a piston pump which has a cylinder 1 provided with an intake valve 4 and an exhaust valve 5, and the piston 6 which slides along the inner wall of the cylinder 1. The piston 6 is fixed to one end of a tube 14 in which high volatile refrigerant 16 and its vapour 17 are stored inside gastightly, and the other end of the tube 14 is connected vent free to a vessel 15 in which the refrigerant 16, its vapour 17 and a heating element 18 are stored, through a tube 22 fixed to the bottom of the cylinder 1. A cooler 19 is mounted outside the tube 22 and on.off of the heating element 18 and the cooler 19, calorific value of the heating element and cooler performance, are controlled by a controller 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piston pump for conveying gas or liquid.

[0002]

2. Description of the Related Art In a conventional piston pump for conveying gas or liquid, a motor rotates a crankshaft and a rod connected to the crank moves the piston up and down. FIG. 3 shows an example of a conventional piston pump. An intake port 2 and an exhaust port 3 are provided above the cylinder 1, and an intake valve 4 and an exhaust valve 5 are provided in each. In the cylinder 1 there is a piston 6
Is installed so that it can slide up and down in the cylinder 1. At the bottom of the cylinder 1 is a crankshaft 8 supported by bearings 7, which connects the piston 6 and the crankshaft 8 to a rod 9
It is connected. The crankshaft 8 is the output shaft 1 of the motor 10.
It is connected to 1. A controller 12 is connected to the motor 10. In such a configuration, when the controller 12 issues a start command, the motor 10 starts to rotate and the crankshaft 8 connected to the output shaft 11 starts to rotate. By the link mechanism composed of the crankshaft 8 and the rod 9, the rotational movement of the crankshaft 8 is converted into the reciprocating linear movement of the piston 6 connected by the rod 9 in the cylinder 1. When the piston 6 descends, the air chamber 13
Since the pressure in the inside decreases, the intake valve 4 opens and the intake port 2
When the air flows in through the piston 6 and the piston 6 rises, the pressure in the air chamber 13 increases, so that the exhaust valve 5 opens and the air is exhausted from the intake port 3. This operation is repeated by the continuous rotation of the motor 10 to function as a piston pump.

[0003]

However, in the prior art, (1) since the motor is used as the drive source, the overall structure becomes large. (2) Vibration and noise are generated because there are unbalanced members such as the crankshaft and rod. There was a problem. Therefore, an object of the present invention is to provide a piston pump that solves the above problems.

[0004]

In order to solve the above problems, in a piston pump provided with a cylinder provided with an intake valve and an exhaust valve and a piston sliding along an inner wall of the cylinder, one end of the piston is It is fixed to one end of a tube with a highly volatile refrigerant liquid and its vapor inside that has a bellows inside, and the other end of the tube is vented with a container containing the refrigerant liquid and its vapor and heating element. Connect freely,
A cooler is attached to the outside of the container, and a controller controls on / off of the heat generating element and the cooler, the amount of heat generated by the heat generating element, and the capacity of the cooler.

[0005]

By the above means, the amount of steam in the container is controlled by controlling the amount of heat generated by the heating element and the cooling capacity of the cooler.
By cyclically changing the balance between the pressure in the container and the pressure in the cylinder, the piston in the cylinder reciprocates, and the pump action is made in conjunction with the intake and exhaust valves.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. 1 by taking an air pump as an example. An intake port 2 and an exhaust port 3 are provided above the cylinder 1, and an intake valve 4 and an exhaust valve 5 are provided respectively.
Is provided. A piston 6 is installed in the cylinder 1 so that it can slide up and down in the cylinder 1. A tube 1 in which a bellows 21 is partially provided at the bottom of the piston 6.
4 is fixed, and the tube 14 is connected to the container 15 through the tube 22 fixed to the bottom of the cylinder 1 so as to be freely ventilated. In the container 15, a highly volatile refrigerant liquid 16 (for example, Fluorinert: trade name), its refrigerant vapor 17 and a heating element 18 are stored.
A cooler 19 is attached to a part of the outer wall of the. Further, a controller 20 for controlling the on / off timing and heating amount of the heating element 18 and the cooling capacity of the cooler 19 is installed. The tube 14, the bellows 21 and the tube 22 may be integrally formed, and the cooler 19 and the container 15 may be integrally fixed to the bottom of the cylinder 1. In such a configuration, when the cooler 19 is turned off and the heating element 18 is caused to generate heat, the temperatures of the refrigerant liquid 16 and the refrigerant vapor 17 rise and a boiling phenomenon occurs on the surface of the heating element 18 so that the refrigerant liquid 1
6 is vaporized and steam is generated. Therefore, the internal pressure of the container 15 and the tube 14 rises according to the temperature-vapor pressure characteristic of the refrigerant. (See FIG. 4, a graph of Fluorinert temperature-vapor pressure characteristics) When the vapor pressure becomes higher than the pressure of the air chamber 13 in the cylinder 1, the bellows 21 provided in a part of the tube 14 extends and the piston 6 moves. Move up. Therefore, the air chamber 13
Pressure rises from the outside, the exhaust valve 5 opens, and the exhaust port 3
The air in the air chamber 13 is discharged from. Piston 6
When the temperature reaches near the top dead center set in advance, the heating element 18 is turned off and the cooler 19 is turned on to cool the refrigerant liquid 16 and the refrigerant vapor 17. Then, the container 15 and the tube 14
The refrigerant vapor 17 therein condenses to reduce the amount of vapor, the temperatures of the refrigerant liquid 16 and the refrigerant vapor 17 decrease, and the internal pressures of the container 15 and the tube 14 decrease according to the temperature-vapor pressure characteristics. When this vapor pressure becomes lower than the pressure of the air chamber 13, the bellows 21 provided in a part of the tube 14 contracts and the piston 6 moves downward. Therefore, the pressure in the air chamber 13 becomes lower than the outside, the intake valve 4 opens, and air is sucked into the air chamber 13 from the intake port 2. The rate of pressure change of the refrigerant vapor is determined by the temperature change rate of the refrigerant and the rate of increase / decrease of the vapor amount, and each is represented by the following equation. Refrigerant temperature change rate = heating or endotherm / [refrigerant volume x
Specific weight × specific heat] Rate of increase / decrease of vapor amount (volume) = heating or endothermic amount / [specific weight × latent heat] Therefore, the pressure change of the refrigerant vapor by manipulating the heating amount of the heating element and the cooling capacity of the cooler, that is, It can be seen that the speed of the piston 6 can be controlled. That is, if the controller 20 controls the on / off timing of the heating element and the cooler, the heating amount, and the cooling capacity and repeats the above operation, the piston 6 continues the reciprocating motion in the cylinder 1 and functions as a piston pump. To do. If a refrigerant having a small specific weight, specific heat, and latent heat is selected and the usage amount is reduced as much as possible, the time constant for control is shortened, and the movement of the piston can be controlled by slight heating and heat absorption. By the way, in the Fluorinert described in this embodiment, the specific heat is 1/4 of water and the latent heat is 1/27. FIG. 2 shows another embodiment. In the embodiment shown in FIG. 1 described above, since the heating element 18 is hermetically sealed in the container 15, there is a drawback in that it is difficult to perform maintenance inspection for a failure. Therefore, the heating element 18 is attached to the outside of the container 15 and
The structure is such that the refrigerant liquid 16 and the refrigerant vapor 17 are heated via. By doing so, maintenance and inspection of the heating element 18 can be easily performed.

[0007]

As described above, according to the present invention, since the pressure change of the refrigerant vapor with respect to the temperature change is used as the driving force of the piston, there are no mechanically movable parts, and no sound or vibration is generated. The effect is that the structure is also small. Further, as shown below, there is an effect that the performance of the pump can be freely changed by controlling the heating element and the cooler. (1) The stroke of the piston can be controlled by changing the on / off timing of the heating element and the cooler, and the speed can be controlled by changing the amount of heat generation and the capacity of the cooler, so that the amount of fluid transfer can be changed. .. (2) Since the temperature of the refrigerant vapor, that is, the pressure level of the vapor can be controlled by changing the balance between the heat generation amount and the cooling capacity, it is possible to respond to the pressure change of the fluid to be conveyed.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment of the present invention.

FIG. 2 is a side sectional view showing another embodiment.

FIG. 3 is a side sectional view showing a conventional example.

FIG. 4 is a graph of temperature-vapor pressure characteristics of Fluorinert.

[Explanation of symbols]

 1 Cylinder 2 Inlet port 3 Exhaust port 4 Intake valve 5 Exhaust valve 6 Piston 7 Bearing 8 Crankshaft 9 Rod 10 Motor 11 Output shaft 12 Controller 13 Air chamber 14, 22 Tube 15 Container 16 Refrigerant liquid 17 Refrigerant vapor 18 Heating element 19 Cooling Vessel 20 controller 21 bellows

Claims (2)

[Claims] 1. A piston pump provided with a cylinder provided with an intake valve and an exhaust valve and a piston sliding along an inner wall of the cylinder, wherein a bellows is partially provided and fixed to an end of the piston A tube containing a highly volatile refrigerant liquid and its vapor in an airtight manner, a container containing the refrigerant liquid, its vapor and a heating element, which is connected to the other end of the tube in a ventilated manner, and a cooling attached to the outer circumference of the tube. A piston pump comprising a heater and a controller that controls the on / off of the heating element, the amount of heat generated by the heating element, and the cooling capacity of the cooler. 2. The piston pump according to claim 1, wherein the heating element is mounted outside the container.