JPH059283Y2 - - Google Patents

Description

[Detailed Description of the Invention] a. Field of Industrial Application The present invention relates to a nozzle with a small check valve that is effective in preventing backflow of powder, etc.

b. Prior Art A nozzle is generally a type of nozzle as shown in Fig. 4a and b.
The cross-sectional area of the outlet portion 103 is reduced relative to the fluid inlet portion 102, and a part of the pressure head of the fluid is converted into a velocity head, thereby being used as a spout that jets out fluid forcefully. It is.

An example of a case where such a general conventional nozzle 101 is used in a powder bagging device will be explained with reference to FIG. 5.

The powder enters the duct 107 from the hopper 104 and is sent to the air outlet 110 via the screw conveyor chambers 108, 109 by the screw conveyors 105, 106.
In the ring nozzle 111 and the nozzle 101
It is fluidized by the air ejected from the powder, and is filled into the paper bag 114 through the pinch valve 112 and the expansion tube 113 as powder fluid.

When a predetermined amount of powder is filled into the paper bag 114, the load detection device 115 senses it.
Powder filling stop operation is performed. That is, closing the pinch valve 112 and closing the screw conveyor 10.
5 and 106, and the air supply to the nozzle 101 is stopped at the same time.

With this operation, the step of measuring and bagging the powder is completed.

c. Problems to be solved by the invention However, in a powder bagging device that uses the conventional nozzle 101 as is, when the powder filling reaches a predetermined amount, the pinch valve 112 is closed;
The screw conveyors 105 and 106 are stopped, the air supply to the nozzle 101 is stopped, etc. at the same time, but at this time, a phenomenon occurs in which the pressure inside the nozzle 101 becomes lower than the pressure at the air jet port 110. As a result, the powder present in the air outlet 110 flows into the nozzle 101, causing a phenomenon in which the nozzle is blocked.

This clogging phenomenon tends to become more noticeable when the amount of powder packed per bag is increased or when the filling speed is increased.

The nozzle 101 is an important device in such a powder bagging device in order to improve measurement accuracy, and if the nozzle is blocked, the powder cannot be fluidized.
Weighing accuracy decreases significantly. Furthermore, repairing the nozzle takes time and effort, resulting in a significant decrease in bagging productivity.

One way to prevent the blockage phenomenon is to install a check valve in the nozzle, but a check valve with a small diameter such as a nozzle has a small passage area, so it is difficult to operate effectively by installing it in such a narrow passage. Check valves are generally not found, and conventionally, this has been dealt with by lowering the filling amount and filling speed, and as a result, productivity has been unavoidably sacrificed.

The present invention was devised to effectively solve the above-mentioned problems, and its purpose is to create a so-called check valve that can prevent the backflow of fluid without impairing its effectiveness as a nozzle. The objective is to provide a nozzle with a

d Means for Solving the Problems In order to solve the above-mentioned problems, the gist of the present invention is to provide an inlet passage bored in the longitudinal direction of the main body, a valve chamber having a cross-sectional area larger than that of the inlet passage, and a valve chamber having a cross-sectional area larger than the inlet passage. A plurality of very small passages are bored in the valve body receiving part provided at the rear in a direction substantially perpendicular to the inlet passage so as to communicate with each other near the center of the valve body receiving part, and the cross-sectional area thereof is larger than the cross-sectional area of the one said very small passage. and a valve body whose cross-sectional area is smaller than the cross-sectional area of the valve chamber and larger than the inlet passage is slidably housed in the valve chamber, and the valve body is in communication with the outlet passages whose total cross-sectional area is less than the total cross-sectional area of the valve chamber. The nozzle is equipped with a check valve.

e Function The above-mentioned nozzle with a check valve is used in a powder bagging device, etc., and the function in that case is as follows.

First, when air is introduced from the inlet passage side, the valve body is pressed against the valve body receiving portion by the air supply pressure, and the inlet passage is opened. Therefore, air flows into the outlet passage through the inlet passage, the valve chamber, and the very small passage, and is ejected from the open end of the outlet passage, fluidizing the powder and turning it into powder fluid. At this time, since the cross-sectional area of the outlet passage is smaller than the total cross-sectional area of the very small passages, the present device exhibits its effect as a nozzle.

Conversely, if the pinch valve is closed and the air supply is stopped, causing back pressure,
The pressure passes through the outlet passage and the very small passage, and forces the valve body in the valve chamber against the inlet passage, thereby closing the passage. Therefore, the powder fluid does not flow backward in the nozzle, and the nozzle can be prevented from being blocked. In this case, the nozzle according to the invention acts as a check valve.

f. Example Hereinafter, an example using a nozzle with a check valve according to the present invention will be described with reference to the accompanying drawings.

FIG. 2 is a schematic diagram of a powder bagging device. Here, 11 is a hopper for storing powder such as resin or food products, 12 is a duct connected to the opening of the hopper 11, and 13 is a first screw conveyor installed below the duct 12.

The first screw conveyor 13 is rotated by the rotational force of the drive motor 14 transmitted by the belt 15, and the powder is transferred from the lower part 17 of the duct to the second screw located to the left in the first screw conveyor chamber 16. It is conveyed to the passage 18 to the conveyor chamber 19.

20 is a second screw conveyor. The second screw conveyor 20 also rotates as the rotational force of the drive motor 21 is transmitted through the belt 22, and the powder is transferred to the passage 1 in the second screw conveyor chamber 19.
8 to the air outlet 23.

The shaft 20a of the second screw conveyor 20 is hollow, as shown in the enlarged view of the main parts of the apparatus of this embodiment in FIG. A nozzle 1 with a check valve according to the present invention is installed in each of the nozzles. Therefore, the air is sucked by the blower 24 and the shaft 2
It passes through the hollow part 0a and is ejected from the nozzle 1 with a check valve.

As shown in FIG. 1, the nozzle 1 with a check valve includes an air inlet passage 2 bored in the longitudinal direction, a valve chamber 3 having a larger cross-sectional area than the inlet passage 2, and a valve provided at the rear of the valve chamber 3. A plurality of very small passages 5 are bored in the body receiving part 4 in a direction substantially perpendicular to the inlet passage 2 so as to communicate near the center of the valve body receiving part, and the cross-sectional area thereof is larger than the cross-sectional area of one of the above-mentioned very small passages 5. , and a valve body 7 whose cross-sectional area is smaller than the cross-sectional area of the valve chamber and larger than the inlet passage is slidably housed in the valve chamber 3, and the valve body 7 is in communication with an outlet passage 6 having a total cross-sectional area of less than the total cross-sectional area of the valve chamber. It is.

The material of this nozzle 1 with a check valve is not particularly limited, but metal and synthetic resin are preferable, and metal is more preferable. In order to reduce pressure loss, the cross-sectional area of the inlet passage 2 is larger than the cross-sectional area of the outlet passage 6, preferably in a cross-sectional area ratio of 1.1 to 20, particularly preferably 1.2 to the outlet passage 1.
~15. The shape of the valve body 7 is not particularly limited as long as it has a closing property when it comes into contact with the inlet passage 2, but a sphere is preferable in terms of performance.
The cross-sectional area of the outlet passage 6 is preferably 0.03 mm ² to 20.00
^mm2 , more preferably ^0.20mm2 to ^10.00mm2 ,
When the outlet passage having this cross-sectional area is used in a powder bagging apparatus as in this embodiment, it effectively functions as a check valve for powder fluid. The shapes of the very small passage 5 and the outlet passage 6 are not particularly limited, and may be square, oval, circular, or the like. The cross-sectional shape of the inlet passage 2 may be any shape as long as it can be closed when it comes into contact with the valve body 7, and is preferably circular.

In addition, a ring nozzle 26 and a pinch valve 2 are installed in the left opening part 25 of the second screw conveyor chamber 19.
7. Connect the expansion tubes 28 in sequence and provide a discharge port 29 at the end thereof. 30 is a paper bag, and 31 is a load detection device for detecting the amount of powder filled in the paper bag 30.

The expansion tube 28 has the function of expanding with air pressure to prevent the fluidized powder from scattering from the inlet of the paper bag 30, thereby improving the sealing performance with the inlet. The load detection device 31 is such that when powder enters the paper bag 30, the load cell bends due to the weight of the powder, and the amount of strain is electrically converted into weight to measure the weight.

Next, the operating status of this powder bagging device will be explained.

The powder stored in the hopper 11 is sent to the air outlet 23 through the duct 12, the first and second screw conveyor chambers 16, 19, by the rotation of the first and second screw conveyors 13 and 20. . At the air spout 23, the powder is fluidized by the air jetted from the nozzle 1 with a check valve, and is filled into the paper bag 30 through the pinch valve 27 and the expansion tube 28 as a powder fluid.

When the paper bag 30 is filled with a predetermined amount of powder, the load detection device 31 senses it and closes the pinch valve 27 and closes the first and second screws by electrical means (not shown) to stop the powder filling. The conveyors 13 and 20 are stopped, the air supply to the check valve nozzle 1 is stopped, that is, the blower 24 is stopped, etc. at the same time.

In order to exhaust the air blown out from the check valve nozzle 1 used to fluidize the filling powder from inside the paper bag 30, the air is suctioned by a pressurized air ejector 32.

With the above operations, the powder weighing and bagging process is completed.

An example will be shown in which ABS resin powder was packed into bags using the above-mentioned example apparatus. The bagging conditions are as follows.

Weight of one bag filled: 25Kg Bagging speed: 1 bag/40 seconds Bagging operation time: 10 hours The results are above for the set weight of 25Kg per bag.
The average value per bag obtained after 10 hours of operation was 25.035 Kg, and the variation was within ±40 g.

In addition, when an experiment was conducted without using the nozzle 1 with a check valve according to the present invention and instead using the conventional nozzle 101 under the same conditions as in the previous example, the average value per bag was 25.061 kg. The variation was ±150 to 250 g.

g. Effects of the invention Since the present invention is a nozzle with a check valve having the structure described above, when it is desired to prevent the fluid from flowing back into the nozzle after ejection, for example, it prevents the nozzle from being blocked by powder fluid as in the embodiment. The present invention provides an effective nozzle for such purposes.

In particular, in the nozzle with a check valve according to the present invention, a plurality of very small passages leading to the valve chamber are bored in a direction substantially perpendicular to the outlet passage, and the cross-sectional area of one of the small passages is equal to that of the outlet passage. When the cross-sectional area is less than or equal to , it is possible to effectively prevent powder fluid, etc., from entering.

Furthermore, since the structure of the present invention is simple with a valve chamber and a valve body provided in the fluid passage of the nozzle,
Even when used in narrow passages, it is easier to manufacture than those with a structure in which the valve body is held down by a spring, etc., and there is no risk of the spring breaking and getting mixed in with the ejected fluid, etc., and has various advantages. This is a new idea.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a nozzle with a check valve according to the present invention, and FIG. 2 is a schematic diagram of a powder bagging device showing an embodiment using the nozzle with a check valve according to the present invention.
FIG. 3 is an enlarged view of the main parts of the powder bagging apparatus.
FIGS. 4a and 4b are vertical cross-sectional views of a conventional nozzle, and
FIG. 5 is a schematic diagram of a powder bagging apparatus using a conventional nozzle. 1... Nozzle body with check valve, 2... Inlet passage,
3... Valve chamber, 4... Valve body receiving part, 5... Very small passage, 6... Outlet passage, 7... Valve body, 11... Hopper, 12... Duct, 13, 20... Screw conveyor , 23... Air spout, 24... Blower, 27... Pinch valve, 28... Expansion pipe,
30...Paper bag, 31...Load detection device.

Claims (1)

[Scope of utility model registration request] An inlet passage bored in the longitudinal direction of the main body, a valve chamber having a larger cross-sectional area than the inlet passage, and a plurality of valve body holders arranged substantially perpendicular to the inlet passage in a valve body holder provided at the rear of the valve chamber. A very small passage bored near the center of the valve chamber and an outlet passage whose cross-sectional area is greater than or equal to the cross-sectional area of one of the above-mentioned very small passages and less than the total cross-sectional area thereof are communicated with each other, and within the valve chamber. A nozzle with a check valve, characterized in that a valve body whose cross-sectional area is smaller than the cross-sectional area of the valve chamber and larger than the inlet passage is slidably housed.