JPS5841417B2 - solar heat collector tube - Google Patents

Description

[Detailed description of the invention] Two bottomed straight glass tubes with different diameters, one end of which is closed by rounding and the other end is open, are stacked concentrically to form both the inner and outer tubes. Vacuum double-front type solar heat collector tubes that are sealed and depressurized between each other are widely used in solar heat collectors, but this type of solar heat collector tube is easy to vacuum seal between the heat-receiving inner tube and the outer glass tube. In order to
A small diameter glass tube for exhaust is previously provided at the bottom of the outer glass tube.

However, the exhaust pipe is formed in a series during the rounding process of manufacturing the outer glass tube, or by welding a separately formed small-diameter glass exhaust pipe to the bottom of the rounded outer tube. Because it is provided,
In addition to glass processing techniques used in round processing, drawing processing, drilling processing that requires skill, and welding processing are required, which inevitably increases the cost of the outer tube.

Furthermore, if a mistake is made in this process, the entire outer glass tube becomes unusable, which is uneconomical.

In addition, since the bottom of the conventional outer glass tube connected to the small-diameter glass tube for exhaust has a thin wall thickness at the bottom, when sealing and cutting the exhaust tube after depressurization, it is necessary to cut the remaining tails of both tubes as much as possible. It was necessary to keep the tail short and to always be careful not to damage the bottom part even if an impact force was applied to the remaining part of the tail.

However, if an attempt is made to shorten the remaining portion of the tail, the glass melting heat applied during seal cutting is transmitted to the bottom of the outer glass tube and melts that part, causing the inconvenience of making the bottom wall even thinner. For this reason, the brittle bottom of conventional solar heat collection tubes has been a problem.

The present invention shows that there is room for improvement in the manufacturing cost of the conventional vacuum double-front type solar collector tube, and in particular, the quality of the post-treatment of the small diameter glass tube for exhaust after the depressurization process affects the yield in solar collector tube manufacturing. In view of the above, the present invention relates to a solar heat collecting tube invented with the aim of eliminating such disadvantages and drawbacks, and one embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a partially cutaway side view showing the installed state of the solar heat collecting pipe of the present invention, and FIG. 2 is a quarter cutaway side view of the vicinity of the bottom showing the state of the solar heat collecting pipe of the present invention before vacuum sealing. FIG. 3 is a front view of the bottom viewed from the left side of FIG. 2, and FIG. 4 is a front view of the bottom member. First, in FIG. In FIG. 4, 3 is a circular glass lid member for forming a bottom piece for closing the - side open end 4 of the straight pipe 1, and a small exhaust hole 5 is bored in the center of the lid member 3. A small-diameter glass tube 6 for exhaust is welded to the small hole 5 to form the bottom member 7, and the peripheral edge of the bottom member 70 is welded to the open end 4 of the straight glass tube 1 as shown in FIG. It is attached to form the bottom part.

Further, the circular glass lid material 3 which is the main body of the bottom member 7 is a second
As shown in the figure, the - side, that is, the bottom forming surface has a flat surface, while the other side has a required width concentric with the center hole 5 of the lid member 3, as shown in FIG. An annular groove 8 and an annular protrusion 9 of a required width are concentrically formed adjacent to the outer periphery of the interspace groove 8, and the small diameter exhaust pipe 6 is protruded from the surface where the annular groove 8 and the protrusion 9 are formed. has been done.

Reference numeral 10 denotes an inner glass tube (hereinafter referred to as the inner tube) which is overlapped in a double layer concentrically with the outer tube 2, and its material is a straight glass tube with both ends open like the outer tube 2. Round processing is applied to form a rounded bottom, and furthermore,
The entire outer surface has high absorption in the solar radiation spectral range;
Both the inner and outer tubes 2 are coated with a black so-called selective absorption film surface 11 that has a characteristic of having a small emissivity in the thermal radiation spectrum region.
The open end of the opening at 10° is hermetically welded together.

The air existing between the outer tube 2 and the inner tube 10 is degassed to a predetermined degree of vacuum by a vacuum pump connected to the exhaust pipe 6, and after degassing, the vicinity of the base of the exhaust pipe 6 is heated with an electric tip. A tail 12 is formed at the bottom of the outer tube 2 by cutting in a sealed manner as shown in FIG.

14 is a frame of the solar heat collector; 13 is a spring that supports the bottom of the solar heat collector tube; the spring 13 is received by the side surface of the annular protrusion 9 formed on the bottom member T of the outer tube; It is designed to be pressed in the right direction in Figure 1.

Thus, the solar heat collecting tube of the present invention has a small exhaust hole 5 in the center at one open end 3 of the straight glass tube 1, which is open at both ends.
and a small diameter exhaust pipe 6 is connected to the small hole 5, and
An outer pipe 2 is formed by airtightly fixing a bottom member T having an annular groove 8 and an annular protrusion 9 concentrically formed between the connecting portions of a small-diameter exhaust pipe 6, and closing the open end in a planar manner. , the inner tube 10 has a bottom formed by round processing and a black surface 11 having characteristics of high absorption in the solar radiation spectral range and low emissivity in the thermal radiation spectral range on the outer surface, and a required gap is provided. Both the inner and outer tubes 2.
10 to the required degree of vacuum, and the small diameter exhaust pipe 6
Since the outer tube 2 is cut and closed near its base, the solar heat collecting tube of the present invention can easily manufacture the outer tube 2 without requiring any skill. Since the bottom member T is configured at the bottom of the glass straight pipe 1, there is no possibility of causing work errors when manufacturing the bottom member 7 or when fixing the bottom member 7 airtight, that is, when forming the bottom. Even if a work error were to occur during the production of material I, the damage would not spread to the entire heat collecting pipe, and the damage would be slightly affected by the lid material 3 forming the bottom member 7 or the small diameter exhaust pipe 6. Since you can stop yourself from running out of work, you don't have to worry about losing your economy due to work errors, unlike in the past.

Furthermore, in the solar heat collecting tube of the present invention, the annular groove 8 is formed on the protruding surface of the small diameter exhaust pipe 6 of the lid member 3 constituting the bottom member 7 of the outer tube 2. In tip-off work), the heater used in that work can be separated from the surface of the lid member 3 by the depth D of the annular groove 8, so that the radiant heat emitted from the heater is transferred to the tip of the small diameter exhaust pipe 6. It is possible to prevent the tip-off from being transmitted intensively to the off-point and to the cover member 3, and therefore the tip-off operation of the interpipe 6 can be carried out in an extremely short time without melting the cover member 2.

In addition, the cutting position of the exhaust pipe 6 (the right side in FIG. 1) is brought as close as possible to the lid member 3, and the length of the protrusion caused by the base of the glass tube 60 that remains at the bottom of the outer tube after the tip-off operation, that is, the outer tube tail 12, is Since the glass distortion caused when an impact force is applied to the tail 12, the area where the inner and outer tubes connect (near the arrow flB in Figure 1)
This has the effect of being able to prevent accidents that result in damage to the equipment.

Moreover, since the annular protrusion 9 is formed on the lid member 3, when the solar heat collecting tube of the present invention is mounted on the frame, the end of the spring 13 that presses the heat collecting tube in the axial direction can be pressed by the annular protrusion 9. Therefore, the solar heat collecting tube of the present invention also has the effect that its bottom can be kept stable at all times.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and Fig. 1b is a cross-sectional side view of the solar heat collecting tube of the present invention in a state in which it is attached, and Fig. 2 is a side view of the solar heat collecting tube of the present invention before vacuum sealing. FIG. 3 is a front view of the bottom viewed from the left side of FIG. 2, and FIG. 4 is a front view of the lid member. In the drawings, reference numeral 1... glass straight tube for forming an outer tube, 2...
Outer tube, 3... Lid material, 4...-opening end, 5... Small hole for exhaust, 6... Small diameter pipe for exhaust, 7... Bottom member, 8...
... Annular groove, 9... Annular protrusion, 10... Inner tube, 11
... selective absorption membrane, 12 ... outer tube tail, 13 ...
spring.

Claims (1)

[Claims] 1 A straight glass tube with both ends open at one end has a small exhaust hole in the center, and a small diameter exhaust pipe is connected to the small hole, and around the connection part of the small diameter exhaust pipe. The bottom member, in which an annular groove and an annular protrusion are formed concentrically, is fixed airtightly.
The outer tube has an open end that is flatly closed, and the bottom is formed by round processing, and the outer surface has a black surface that has the characteristics of high absorption in the solar radiation spectral range and low emissivity in the thermal radiation spectral range. The prepared inner tubes were overlapped and joined together with the required gap, the pressure was reduced to the required degree of vacuum between the inner and outer tubes, and the small diameter exhaust pipe was cut and closed near its base. Solar heat collector tube.