JPH057512Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a pump that heats the liquid without using any external mechanical drive, and simultaneously heats and pumps the liquid.

Conventionally, heat-driven pumps have been known as pumps that generate pumping action simply by heating the liquid without requiring external power such as a motor or compressor (Magazine Soda and Chlorine 1983, No. 2, pp. 64-77)
(See "About heat-driven pumps"). However, this heat-driven pump is known to have a drawback in that it does not operate well when the amount of heating at pump startup (the amount of heating per unit time) is small. In addition, in order to expand the operating range of the pump with respect to the amount of heating, two heating tubes must be placed one above the other in the heating section, making the structure complex and subject to vertical restrictions when installing. The "Heat Driven Pump" proposed in order to eliminate these drawbacks was able to perform a reliable pumping action even with a small amount of heating, and was no longer subject to any vertical or vertical restrictions when installed. . During implementation, a large temperature difference is created at the joint between the heating section and the tube, so the heating section and the tube are made of different materials with greatly different thermal conductivities, and they have the same coefficient of thermal expansion and can be welded together. Conditions must be met. However, in reality, it is difficult to select a material that satisfies these conditions, so it is necessary to insert another interference material between the heating section and the tube joint, or to devise the shape of the tube. The number of parts increases,
There were problems in that it took time to assemble and the reliability of the pump deteriorated.

The present invention provides a heat-driven pump that is easier to assemble and more reliable than conventional pumps while maintaining a large temperature difference between the heating section and the tube.

According to the present invention, a heat-driven pump has a heating section in which a part of a pipe protrudes from the inside to the outside, check valves are provided at both ends of the pipe, and suction is drawn into the pipe adjacent to the heating section. It is characterized by having a section.

Embodiments of the invention will be described below with reference to the accompanying drawings. In FIG. 1, the heating section has a part of the tube protruding from the inside to the outside to form a conical recess P. The wall thickness of the recess is thinner than that of the tube so that heat applied from the outside can be transferred well. Further, the solid angle of the recess is smaller than the wetting angle between the liquid used and the material of the recess P. The pipes G ₁ and G ₂ are made integrally with the heating section, and check valves CV ₁ and CV ₂ are attached to both ends of the pipes. In addition, as a modified example, the concave portion P may have a cavity R that spreads conically at the apex (the second
figure). The material for the tube is preferably a material that does not easily conduct heat, such as glass, but ceramics, plastics, etc. may also be used. In addition, between the tube _G1 and the heating section B, there is a suction section that is made so that the liquid to be used is well soaked, heat is not easily transmitted, and a capillary force that is larger than that of the tube _G1 is applied to the liquid. I is installed in tube _G1 . Alternatively, as a modification, it may be made integrally with the pipe _G1 . In this example, the suction consists of a tapered hole made of a material with low thermal conductivity. As another modification, as shown in FIGS. 3 and 4, a dividing hole formed by a cross-shaped piece may be provided. The working fluid used may be water, various refrigerants (R-11, R-12, ammonia, etc.), liquid metals, low-melting metals, etc., as long as it evaporates and does not leave any solid matter behind.

Next, the operation of the pump of the present invention will be explained with reference to the explanation of the operation shown in FIGS. 5 to 10.

First, fill the pump with the liquid you will be using. At this time, since the solid angle of the recess P is smaller than the contact angle between the material of the recess and the liquid, the bond cannot completely nullify the recess P, and a bubble nucleus N at the tip of the recess P of the heating section B.
remains (Figure 5). Next, when heating part B is heated uniformly, the concave part is heated uniformly, but since the concave part has a conical shape, the cross-sectional area becomes smaller toward the tip, so the temperature of the liquid in that part becomes faster. is faster than other parts, so when the temperature of the liquid covering the bubble nucleus N rises and exceeds the saturation temperature at the pressure inside the bubble nucleus, evaporation occurs from the liquid side to the bubble side at the bubble nucleus/liquid interface. , the bubble nucleus N starts to grow (6th
figure). Then, the pressure inside the pump rises slightly from the outside of the check valve CV ₂ , and the check valve CV ₂ opens. Then, the check valve CV ₁ is closed. As the bubble grows, its volume is pumped to the outside through the liquid check valve CV ₂ . The growth speed of bubbles is fast. This is because bubbles are formed due to the evaporation of a very small amount of liquid at the tip of the recess and the evaporation of an extremely thin liquid film that is trailed by the gas-liquid interface rising up the recess.
Only a small amount of energy is required to evaporate this small amount of liquid. The rapid growth of bubbles also causes most of the liquid in the heating section that cannot be evaporated to be quickly drained out of the heating section, thereby preventing energy loss due to temperature rise within the heating section.

On the other hand, the liquid in tubes G ₁ and G ₂ absorbs the heat from the heating section.
It is transmitted through G ₁ and G ₂ , but the amount is small because the tubes are made of glass. Furthermore, as described above, due to the rapid growth of bubbles, the liquid in the pipe _G2 is discharged outside through the check valve _CV2 without increasing its temperature much. Therefore, _the bubble expands into the cooled tube G ₂
It is cooled by the inner walls and begins to condense. When the amount of evaporation in the heating section and the amount of condensation are balanced, bubble growth stops (Figure 7). This state is unstable, and eventually the amount of condensation exceeds the amount of condensation, and the bubbles begin to contract, resulting in a slight negative pressure inside the pump. Then check valve CV ₂ closes and the check valve
CV ₁ opens. At this time, since the suction part I is made of a material that wets the liquid well and has holes whose inner diameter decreases toward the heating part side, a pump action works to suck the air-liquid interface into the heating part side by capillary force. When the interface reaches the entrance of the heating section, it is cooled in the vicinity and the bubbles begin to shrink (Figure 8). At this time also tube G ₁
The heat transmitted from the heating part is small because _G1 is a poor thermal conductor. The temperature of the liquid in _G1 does not rise much, and it is effective when being sucked in by the suction part and cooling the vicinity of the entrance of the heating part. Eventually, strong negative pressure is generated due to the drop in bubble temperature, and a large amount of cold liquid flows into the pump from the outside through check valve CV ₁ (No. 9).
figure). This process is a cycle of condensation of bubbles → generation of negative pressure → cold liquid flowing in from G ₁ → lowering the temperature of the bubbles → condensation of the bubbles, and the bubbles instantly collapse.
An amount of liquid corresponding to the volume is supplied from outside. Further, heating of the liquid is performed at the gas-liquid interface or when bubbles condense.

Because it operates on the operating principle described above, a large temperature difference occurs between the tubes G ₁ and G ₂ and the heating section. In particular, there is a large temperature difference before and after the gas-liquid interface, and this interface exists in the suction part of tube _G1 during the bubble growth process, and thermal stress is generated due to the temperature difference in this part (heated part). and pipe _G2 ) is simple and no problem because it is integrated with the pipe and there are no joints. Further, uniform heating of the heating part can be achieved by placing the heating part (at the recessed part) in a heating fluid (for example, combustion gas, high-temperature waste water, etc.).

The heat-driven pump described above has the following features compared to conventional pumps. It operates even with small input energy and has a high rate of conversion of input energy into pumping action. In addition, since the heating section and the tube are made of one piece, it is durable and has a simple structure. Installation is not subject to any restrictions.

The check valve of the present invention needs to be highly sensitive to pressure, and a flapper type, tuck-bill type, umbrella type, etc. are preferable.

This pump works as a pump by introducing liquid from the outside by condensing the liquid and extruded bubbles through evaporation by heating the heated vapor bubbles, but when the external load becomes large (for example, due to a water level difference), it is insufficient for bubble growth. A certain degree of superheating is required, and the bubbles grow tightly in G ₂ , heating the tube G ₂ and making it difficult to enter the contraction process. In order to improve this, as shown in Fig. 11, a heat exchanger EX made of a material with high thermal conductivity is installed between the pipe G ₂ and the liquid introduction pipe G ₀ connected to the check valve CV ₁ . Good to include. In this configuration, the bubbles that have grown inside the tube G ₂ are transferred to the liquid introduction tube G ₀
When a sufficiently cool heat exchanger EX is touched by an external liquid inside, heat is carried away, where air bubbles can condense and be forced into the contraction process, thus increasing the working range and stability of the pump. be able to.

[Brief explanation of the drawing]

1 is a longitudinal sectional view of the heat-driven pump; FIG. 2 is a sectional view of a heating section with a suction section of a different form; FIG. 3 is a cross-sectional view thereof; FIG.
FIG. 11 is a side view as seen from the left side of the figure, FIGS. 5 to 10 are explanations of the operation of the pump of the present invention, and FIG. 11 is a sectional view showing a modification of the pump of the present invention. G ₁ , G ₂ ... pipe, CV ₁ , CV ₂ ... check valve, B...
...heating part, P...conical recess, I...suction part,
EX……Heat exchanger.

Claims (1)

[Scope of utility model registration request] It has a heating section in which a part of a pipe protrudes from the inside to the outside, check valves are provided at both ends of the pipe, and a suction section is arranged inside the pipe adjacent to the heating section. Features: Heat-driven pump.