JP7493890B2 - Weighing Device - Google Patents

Description

The present invention relates to a weighing device that weighs an object while transporting it on a conveyor.

As an example of this type of weighing device, as described in Patent Document 1, there is a weight sorting machine that weighs the objects to be weighed while placing them on a weighing conveyor and transporting them, and then sorts the objects based on the measured weight.

In the weight sorting machine described in Patent Document 1, a weighing unit housing a load sensor consisting of a load cell for weighing the objects to be weighed transported by a weighing conveyor and a storage box housing electrical equipment are connected by an air duct, and air from within the storage box is introduced into the weighing unit by a fan or the like to prevent condensation within the weighing unit.

Japanese Patent No. 6075536

In the above-mentioned Patent Document 1, air is introduced into the weighing unit by a fan or the like, so the load cell that constitutes the load sensor in the weighing unit is directly affected by the flow of the introduced air, which can cause its output to become unstable and reduce the weighing accuracy.

The present invention was developed in response to this situation, and aims to prevent condensation from occurring and reduce the effect of air flow on the load sensor, thereby preventing a decrease in weighing accuracy.

In order to achieve the above objective, the present invention is configured as follows:

(1) A weighing device according to the present invention is a weighing device including a housing for a weighing unit that houses a load sensor for detecting the weight of an object to be weighed that is conveyed by a conveyor,
An air inlet tube is provided which is pulled into the interior of the housing for the measuring section, and one end of the air inlet tube is an air discharge side end which has a smaller diameter than the diameter of the discharge pipeline which communicates with the housing for the measuring section, and is inserted into the discharge pipeline.

According to the present invention, by inserting one end of the air intake pipe, which is the air discharge end, into the discharge pipe that is connected to the housing for the measuring unit, and discharging air into the discharge pipe, air inside the housing for the measuring unit can be drawn in and discharged to the outside together with the air discharged into the discharge pipe, thereby preventing humid air from accumulating inside the housing for the measuring unit and causing condensation.

In addition, the air exhaust end of the air introduction tube exhausts air not inside the housing for the weighing unit in which the load sensor is housed, but inside the exhaust pipe that is connected to the housing for the weighing unit. This prevents the load sensor inside the housing for the weighing unit from being affected by the flow of exhausted air, making its output unstable and reducing the weighing accuracy.

(2) In a preferred embodiment of the present invention, a control unit housing is provided that houses a control unit that controls the driving of the conveyor, the weighing unit housing and the control unit housing are connected in communication with each other by a connecting pipe, and the end of the air introduction pipe on the air discharge side is inserted into a part of the connecting pipe that serves as the discharge pipe.

Normally, the weighing unit housing, which houses a load sensor for detecting the weight of the objects being weighed transported by the conveyor, and the control unit housing, which houses a control unit that controls the driving of the conveyor, are connected in communication with each other by a connecting pipe through which the conveyor driving cable and the signal cable that transmits the load signal from the load sensor pass.

In this embodiment, the connection line is used as an exhaust line that draws in air from inside the housing for the measuring unit and exhausts it to the outside, so there is no need to form a new exhaust line in the housing for the measuring unit.

(3) In one embodiment of the present invention, at least two of the connecting pipelines are provided, and the end of the air inlet pipe on the air exhaust side is inserted into a portion of at least one of the connecting pipelines as the exhaust pipeline.

According to this embodiment, at least two connecting pipes that communicate with the weighing unit housing housing a load sensor for detecting the weight of the objects to be weighed transported by the conveyor and the control unit housing housing a control unit for controlling the driving of the conveyor, for example, a connecting pipe through which a drive cable used to drive the conveyor etc. is inserted and a connecting pipe through which a signal cable that transmits a load signal etc. from the load sensor is inserted, at least one of the two connecting pipes is used as an exhaust pipe that exhausts air inside the weighing unit housing to the outside, and the air exhaust side end of the air introduction pipe can be inserted into a part of the exhaust pipe to be used for exhausting air.

(4) In another embodiment of the present invention, the air discharge side end of the air introduction pipe is inserted into a portion of one of the two connection pipes from inside the housing for the measuring unit, and the air introduction pipe is inserted through the other of the two connection pipes from the housing for the measuring unit to the housing for the control unit, and the other end of the air introduction pipe is pulled out to the outside of the housing for the control unit, and the other end of the air introduction pipe pulled out to the outside of the housing for the control unit is the end on the air introduction side.

According to this embodiment, the other end of the air introduction tube, the air introduction end, is pulled out to the outside of the control unit housing, the air introduction tube inside the control unit housing is inserted through the other of the two connecting pipes that connect the control unit housing and the measuring unit housing and is pulled into the measuring unit housing, and one end of the air introduction tube, the air discharge end, is inserted into a part of one of the two connecting pipes.

In other words, the air introduction pipe is routed from the outside of the control unit housing to the inside of the control unit housing, the other connecting pipe that connects both housings, the inside of the measuring unit housing, and a part of one of the connecting pipes that connects both housings, and the air introduced outside the control unit housing is discharged into the one of the connecting pipes.

Generally, the control unit housing is capable of controlling various devices, and therefore has spare connection holes for use in connecting to these devices. According to this embodiment, the air introduction tube can be pulled into the control unit housing using the spare connection hole in the control unit housing, so there is no need to form a new connection hole for pulling in the air introduction tube.

(5) In another embodiment of the present invention, the one end of the air introduction pipe drawn into the interior of the housing for the measuring unit is branched into two branched ends on the air discharge side, and each branched end is inserted into a part of each of the two connecting pipes from inside the housing for the measuring unit, and the other end of the air introduction pipe is drawn out to the outside of the housing for the measuring unit, and the other end of the air introduction pipe drawn out to the outside of the housing for the measuring unit is the end on the air introduction side.

In this embodiment, the air discharge end, which is one end of the air introduction tube, is branched into two, and each branch end is inserted into a part of each of the two connecting pipes, so that air can be discharged from each branch end into each connecting pipe, thereby drawing in air from inside the measuring unit housing.

(6) In a preferred embodiment of the present invention, the air discharge side end of the air introduction pipe is inserted into a portion of one of the two connection pipes from inside the housing for the measuring unit, and the other side end of the air introduction pipe is pulled out to the outside of the housing for the measuring unit, and the other side end of the air introduction pipe pulled out to the outside of the housing for the measuring unit is the air introduction side end.

In this embodiment, the air discharge end of one end of the air inlet pipe is inserted into a part of one of the two connecting pipes, and air is discharged into the connecting pipe, thereby drawing in air from inside the housing for the measuring unit.

(7) In another embodiment of the present invention, the other end of the air introduction tube is pulled out to the outside of the metering unit housing or the control unit housing via a cable gland.

In this embodiment, the air introduction pipe is pulled out to the outside by a cable gland, which prevents water and dust from entering the inside of the metering unit housing and the control unit housing.

(8) In yet another embodiment of the present invention, air is introduced to the other end of the air introduction tube via an air pressure adjustment device.

In this embodiment, the pressure of the air introduced into the air inlet tube is adjusted by the air pressure regulator, and the amount of air discharged into the connecting pipe from the air discharge end, which is one end of the air inlet tube, can be adjusted, thereby adjusting the amount of air drawn into the measuring unit housing.

In this way, according to the present invention, one end of the air intake tube, the air discharge end, is inserted into a part of the discharge pipe that is connected to the housing for the measuring unit, and air is discharged into the discharge pipe. This draws in air from inside the housing for the measuring unit and discharges it to the outside via the discharge pipe together with the air discharged into the discharge pipe, thereby preventing humid air from accumulating inside the housing for the measuring unit and causing condensation.

In addition, the air exhaust end of the air introduction tube exhausts air not inside the housing for the weighing unit in which the load sensor is housed, but inside the exhaust pipe that is connected to the housing for the weighing unit. This prevents the load sensor inside the housing for the weighing unit from being affected by the flow of exhausted air, making its output unstable and reducing the weighing accuracy.

FIG. 1 is a perspective view of a weighing machine as a weighing device according to one embodiment of the present invention. FIG. 2 is a schematic diagram of the load measuring unit and the control box shown in FIG. FIG. 3 is a schematic diagram of another embodiment of the present invention, corresponding to FIG. FIG. 4 is a schematic diagram of a further embodiment of the present invention, corresponding to FIG. FIG. 5 is a schematic diagram of another embodiment of the present invention, corresponding to FIG. FIG. 6 is a schematic diagram of a further embodiment of the present invention, corresponding to FIG.

The following describes an embodiment of the present invention with reference to the drawings.

[Embodiment 1]
A weighing device according to an embodiment of the present invention is shown in Fig. 1. In this embodiment, the weighing device will be described as being applied to a weight checker.

This weight sorting machine is intended to be installed, for example, along a transport line for the objects to be weighed, and is made up of a weighing conveyor 1 that weighs the objects as they are transported, an input conveyor 2 that feeds the objects to be weighed onto the weighing conveyor 1, a load measuring unit 3 equipped with a load sensor such as a load cell, and a setting display 4 that displays the weighing values and allows various settings to be made, as well as a control box 5 that serves as a housing for the control unit and houses the control unit, all of which are supported on a base 6 placed on the floor.

In this weight sorting machine, the objects to be weighed supplied by the carry-in conveyor 2 are transferred to the weighing conveyor 1 for transport, and during this transport the weight of the entire weighing conveyor 1 including the objects to be weighed is weighed by the load measuring unit 3 to calculate the weight of the objects to be weighed, and the weight of the objects to be weighed is determined to be, for example, "light," "appropriate," or "excessive," and sorted by a sorting device (not shown) at a downstream stage.

Figure 2 is a schematic diagram of the load measuring unit 3 and control box 5 that measure the weight of the entire weighing conveyor 1.

The load measuring section 3 below the weighing conveyor 1 is equipped with a weighing unit case 7 made of metal or resin as a housing for the weighing section, and a load sensor 8 consisting of a load cell and the like are housed inside the weighing unit case 7. The end of the fixed side (left side in the figure) of the load sensor 8 is attached via a mounting bolt (not shown) to a fixed part mounting fixture 9 erected inside the weighing unit case 7, and the end of the movable side (right side in the figure) of the load sensor 8 is attached via a mounting bolt (not shown) to a bracket 13 from which a support post 12 that receives the load of the support base 10 that supports the weighing conveyor 1 is protruding.

A bellows-shaped, flexible, expandable cover 14 is attached between the top surface of the weighing unit case 7 and the support base 10 so as to cover the outer periphery of the support 12, and is configured to prevent water, dust, etc. from entering the inside of the weighing unit case 7.

The load of the weighing conveyor 1 acts on the bracket 13 via the support base 10 and the support column 12, and the movable end of the load sensor 8 connected to this bracket 13 bends, thereby measuring the weight of the entire weighing conveyor 1.

An A/D board 15 is attached to the fixed attachment fixture 9 to which the fixed end (left side in the figure) of the load sensor 8 is attached. This A/D board 15 is equipped with an A/D conversion circuit that converts the analog load signal from the load sensor 8 into a digital load signal, and a temperature sensor that detects the internal temperature of the weighing unit case 7 near the load sensor 8. Based on the temperature detected by this temperature sensor, the variation in the output value of the load sensor 8 due to temperature fluctuations is corrected.

The control box 5, which serves as the housing for the control unit, is constructed in the shape of a vertically long box using stainless steel plate or the like. This control box 5 incorporates a board unit 16 that constitutes the control unit that performs drive control of the weighing conveyor 1, and includes a control calculation board that calculates the weight of the object to be weighed based on the digital load signal from the A/D board 15, a power supply unit 17 that supplies power to each unit, a motor driver 18 for driving the conveyor, a noise filter 19 that removes noise from the power line, a terminal block 20, etc.

The measuring unit case 7 as the housing for the measuring section and the control box 5 as the housing for the control section are connected in communication with each other by at least two first and second connection lines 21 and 22. The first and second connection lines 21 and 22 are formed, for example, by ducts.

An air vent 27 is formed at the bottom of the control box 5 to prevent a pressure difference from occurring between the inside and outside of the control box 5.

Of the first and second connecting pipes 21, 22 that connect the weighing unit case 7 and the control box 5, one connecting pipe 21 (22) has a drive cable (not shown) used to drive the weighing conveyor 1, etc. inserted therethrough, and the other connecting pipe 22 (21) has a signal cable (not shown) inserted therethrough that transmits load signals, etc. from the load sensor 8.

In this embodiment, the following configuration is used to prevent humid air from accumulating inside the weighing unit case 7, which serves as the housing for the weighing section and houses the load sensor 8, causing condensation.

That is, an air introduction pipe 23 for introducing air is drawn into the weighing unit case 7. One end 23a of the air introduction pipe 23 drawn into the inside of the weighing unit case 7 has a smaller diameter than the diameter of the first connection pipe 21 as an exhaust pipe, and is inserted into a part of the first connection pipe 21 from inside the weighing unit case 7. This one end 23a is the end on the air exhaust side. The air introduction pipe 23 is composed of a tube or hose made of flexible resin or rubber.

The length of one end 23a of the air introduction pipe 13 that is inserted into a portion of the first connection pipe 21 serving as an exhaust pipe, i.e., the insertion length of one end 23a that is inserted into the first connection pipe 21, is not particularly limited, but is preferably, for example, several mm to several hundred mm.

The air introduction pipe 23 passes through the second connection pipe 22 from the metering unit case 7 to the control box 5, passes through the inside of the control box 5, and the other end 23b is pulled out to the outside via a cable gland 25 provided on the control box 5. The cable gland 25 seals the portion of the air introduction pipe 23 pulled out from the control box 5.

The other end 23b of the air introduction pipe 23 drawn out to the outside of the control box 5 is the end on the air introduction side, and air from a compressor (not shown) is supplied to the other end 23b via a filter regulator 26 as an air pressure adjustment device. The filter regulator 26 preferably adjusts the air pressure to a low level to reduce the amount of air discharged from the one end 23a of the air introduction pipe 23.

Air introduced from the filter regulator 26 to the other end 23b of the air introduction pipe 23 passes through the inside of the control box 5, and reaches the inside of the measuring unit case 7 by the air introduction pipe 23 inserted through the second connection pipe 22, and is discharged from one end 23a of the air introduction pipe 23 inserted into a part of the first connection pipe 21 into the inside of the first connection pipe 21.

At this time, the air inside the weighing unit case 7 is drawn into the first connecting pipe 21 as shown by arrow A, and is discharged into the inside of the control box 5 via the first connecting pipe 21 together with the air discharged from one end 23a of the air introduction pipe 23.

In this way, the air inside the weighing unit case 7 is discharged into the control box 5 through the first connection line 21, while the air inside the weighing unit case 7 is discharged, and as a result, the air inside the control box 5 flows into the weighing unit case 7 through the first connection line 21 and the second connection line 22, as shown by arrow B, and the air inside the weighing unit case 7 is gradually replaced.

This prevents humid air from accumulating inside the weighing unit case 7 and causing condensation.

Moreover, one end 23a of the air introduction pipe 23 does not discharge air directly into the inside of the weighing unit case 7, but discharges air into the inside of the first connecting pipe 21, so that the load sensor 8 inside the weighing unit case 7 is not affected by the flow of discharged air, and its output becomes unstable, which prevents a decrease in weighing accuracy.

The control box 5 is capable of controlling other devices, such as metal detectors, so connection holes are pre-formed so that these devices can be connected as needed.

In this embodiment, the cable gland 25 for connecting the air introduction pipe 23 to the control box 5 is provided in a connection hole that is already equipped in the control box 5, so there is no need to form a new connection hole in the control box 5 or the weighing unit case 7 for connecting the air introduction pipe 23.

The first and second connection pipes 21 and 22 are pipes through which drive cables and signal cables pass, and have been provided conventionally, so the present invention can be easily applied to existing weight sorters.

[Embodiment 2]
FIG. 3 is a view corresponding to FIG. 2 of another embodiment of the present invention, and the same reference numerals are used to designate parts corresponding to those in FIG.

In this embodiment, an air introduction pipe 23 for introducing air is drawn into the weighing unit case 7, and one end 23a of this air introduction pipe 23 is branched into two via a branch connector 24. The first and second branched ends 23a1 and 23a2 are inserted from the inside of the weighing unit case 7 into parts of the first and second connection pipes 21 and 22, which serve as exhaust pipes, respectively.

The other end 23b of the air introduction pipe 23 is pulled out to the outside of the weighing unit case 7 via a cable gland 25.

Air from a compressor (not shown) is supplied to the other end 23b of the air intake pipe 23, with the air pressure adjusted by a filter regulator 26.

As a result, the air supplied from the filter regulator 26 to the other end 23b of the air introduction pipe 23 is discharged from the first and second branch ends 23a1 and 23a2 branched by the branch connector 24 inside the metering unit case 7 into the first and second connection pipes 21 and 22, respectively. At this time, the air inside the metering unit case 7 is drawn into the first and second connection pipes 21 and 22, as shown by arrow A, and is discharged into the control box 5 via the first and second connection pipes 21 together with the air discharged from the first and second branch ends 23a1 and 23a2 of the air introduction pipe 23, respectively.

In this way, the air inside the weighing unit case 7 is discharged into the control box 5 through the first and second connecting pipes 21 and 22, while as the air inside the weighing unit case 7 is discharged, the air inside the control box 5 flows into the weighing unit case 7 through the first and second connecting pipes 21 and 22, as shown by arrow B, and the air inside the weighing unit case 7 is gradually replaced.

As described above, the air discharge end, which is the end 23a on one side of the air introduction pipe 23, is branched into two, and the first and second branched ends 23a1 and 23a2 are inserted into parts of the first and second connecting pipes 21 and 22, respectively, to discharge air into each connecting pipe 21 and 22. This makes it possible to increase the amount of air drawn into the weighing unit case 7 compared to a configuration in which an unbranched air discharge end is inserted into a part of one connecting pipe to discharge air, and therefore makes it possible to more effectively prevent air from accumulating in the weighing unit case 7 and causing condensation.

In addition, air is not discharged directly from the air inlet pipe 23 into the weighing unit case 7, but rather from the first and second branch ends 23a1 and 23a2 of the air inlet pipe 23, which are inserted into parts of the first and second connecting pipes 21 and 22, respectively. This prevents the load sensor 8 in the weighing unit case 7 from being affected by the flow of discharged air, making its output unstable and reducing the weighing accuracy.

Furthermore, the other end 23b of the air introduction pipe 23 can be pulled out from the weighing unit case 7 to introduce air, making it easy to route the air introduction pipe 23.

[Embodiment 3]
FIG. 4 is a view of still another embodiment of the present invention and corresponds to FIG. 2, and the same reference numerals are used to designate the same parts as in FIG.

In this embodiment, an air inlet pipe 23 for introducing air is pulled into the weighing unit case 7, and one end 23a of this air inlet pipe 23 is inserted from the inside of the weighing unit case 7 into a part of the second connection pipe 22 as an exhaust pipe.

The other end 23b of the air introduction pipe 23 is pulled out to the outside of the weighing unit case 7 via a cable gland 25.

Air from a compressor (not shown) is supplied to the other end 23b of the air intake pipe 23, with the air pressure adjusted by a filter regulator 26.

As a result, the air supplied from the filter regulator 26 to the other end 23b of the air inlet pipe 23 is discharged from one end 23a of the air inlet pipe 23 into the inside of the second connection pipe 22. At this time, as shown by arrow A, the air inside the metering unit case 7 is drawn into the second connection pipe 22 and is discharged into the inside of the control box 5 via the second connection pipe 22 together with the air discharged from one end 23a of the air inlet pipe 23.

In this way, the air inside the weighing unit case 7 is discharged into the control box 5 through the second connection line 22, while as the air inside the weighing unit case 7 is discharged, the air inside the control box 5 flows into the weighing unit case 7 through the first connection line 21, and the air inside the weighing unit case 7 is gradually replaced.

This prevents humid air from accumulating inside the weighing unit case 7 and causing condensation.

In addition, one end 23a of the air introduction pipe 23 does not discharge air directly into the inside of the weighing unit case 7, but instead discharges air into the inside of the second connecting pipe 22, so that the load sensor 8 inside the weighing unit case 7 is not affected by the flow of discharged air, and its output becomes unstable, which prevents a decrease in weighing accuracy.

In addition, the other end 23b of the air introduction pipe 23 can be pulled out from the weighing unit case 7 to introduce air, making it easy to route the air introduction pipe 23.

[Embodiment 4]
FIG. 5 is a view corresponding to FIG. 2 of another embodiment of the present invention, and the same reference numerals are used to designate parts corresponding to those in FIG.

In each of the above embodiments, the weighing unit case 7 as the housing for the weighing section and the control box 5 as the housing for the control section are connected in communication with each other through two connection pipes 21 and 22, but they may be connected in communication with each other through a single connection pipe.

5, a measuring unit case ₇₁ as a housing for the measuring section and a control box ₅₁ as a housing for the control section are connected in communication with each other through a single connection pipe _221. The diameter of this connection pipe ₂₂₁ is larger than the diameters of the first and second connection pipes 21, 22 in _each of the above-mentioned embodiments, and the above-mentioned drive cable (not shown) and signal cable (not shown) are inserted through this connection pipe 221.

In this embodiment, an air inlet pipe 23 for introducing air is drawn into the measuring unit case ₇₁ , and one end 23a of this air inlet pipe 23 is inserted from the inside of the measuring unit case ₇₁ into a part of the connecting pipe ₂₂₁ serving as an exhaust pipe.

The other end 23b of the air introduction pipe 23 is pulled out to the outside of the weighing unit case 7 via a cable gland 25.

Air from a compressor (not shown) is supplied to the other end 23b of the air intake pipe 23, with the air pressure adjusted by a filter regulator 26.

As a result, air supplied from the filter regulator 26 to the other end 23b of the air introduction pipe 23 is discharged from one end 23a of the air introduction pipe 23 into the connecting pipe _22-1 . At this time, as indicated by arrow A, air inside the measuring unit case _7-1 is drawn into the connecting pipe _22-1 and is discharged into the control box _5-1 via the connecting pipe _22-1 together with the air discharged from one end 23a of the air introduction pipe 23.

In this way, the air inside the weighing unit case ₇₁ is discharged into the control box ₅₁ through the connecting pipeline _22-1 , while as the air inside the weighing unit case ₇₁ is discharged, the air inside the control box ₅₁ flows into the weighing unit case ₇₁ through the connecting pipeline _22-1 , as shown by arrow B, and the air inside the weighing unit case ₇₁ is gradually replaced.

This makes it possible to prevent humid air from accumulating inside the measuring unit case ₇₁ and causing condensation.

Moreover, one end 23a of the air introduction pipe 23 does not directly discharge air into the inside of the weighing unit case ₇₁ , but discharges air into the inside of the connecting pipe _22-1 . This makes it possible to prevent the load sensor 8 in the weighing unit case ₇₁ from being affected by the flow of discharged air, making its output unstable and causing a decrease in weighing accuracy.

Moreover, the other end 23b of the air introduction pipe 23 can be drawn out from the measuring unit case ₇₁ to introduce air, so that the air introduction pipe 23 can be easily routed.

[Embodiment 5]
FIG. 6 is a view of yet another embodiment of the present invention and corresponds to FIG. 2, and parts corresponding to those in FIG. 2 are given the same reference numerals.

In each of the above-described embodiments, the connection pipes 21, 22, and _{221 that} communicate with the weighing unit case 7, ₇₁ as the housing for the weighing section and the control box 5, ₅₁ as the housing for the control section are used as exhaust pipes for exhausting air inside the weighing unit case 7, ₇₁ , but this connection pipe may be omitted.

That is, in the embodiment of FIG. 6, there is no connecting pipe for communicating between the weighing unit case ₇₂ as the housing for the weighing section and the control box ₅₂ as the housing for the control section, and the weighing unit case ₇₂ and the control box ₂ are directly connected by the drive cable 30 and the signal cable 31 described above.

The weighing unit case ₇₂ is provided with a discharge pipe 32 that communicates with the weighing unit case _72. The discharge pipe 32 is formed of, for example, a duct.

One end 23 a of the air introduction pipe 23 drawn into the inside of the measuring unit case ₇₂ , that is, the end on the air discharge side, is inserted into this discharge pipe line 32 .

The other end 23 b of the air introduction pipe 23 is led out to the outside of the measuring unit case ₇₂ via a cable gland 25 .

Air from a compressor (not shown) is supplied to the other end 23b of the air intake pipe 23, with the air pressure adjusted by a filter regulator 26.

As a result, air supplied from the filter regulator 26 to the other end 23b of the air introduction pipe 23 is discharged from one end 23a of the air introduction pipe 23 into the inside of the discharge pipe 32. At this time, as indicated by arrow A, air inside the measuring unit case ₇₂ is drawn into the discharge pipe 32 and discharged to the outside via the discharge pipe 32 together with the air discharged from one end 23a of the air introduction pipe 23.

In this way, the air inside the weighing unit case ₇₂ is discharged to the outside of the weighing unit case ₇₂ via the exhaust pipe 32, while as the air inside the weighing unit case ₇₂ is discharged, the air from the outside flows into the weighing unit case ₇₂ via the exhaust pipe 32, and the air inside the weighing unit case ₇₂ is gradually replaced.

This makes it possible to prevent humid air from accumulating inside the measuring unit case ₇₂ and causing condensation.

Moreover, one end 23a of the air introduction pipe 23 does not directly discharge air into the inside of the weighing unit case ₇₂ , but discharges air into the inside of the discharge pipe 32. This makes it possible to prevent the load sensor 8 in the weighing unit case ₇₂ from being affected by the flow of discharged air, thereby making its output unstable and reducing the weighing accuracy.

Moreover, the other end 23b of the air introduction pipe 23 can be drawn out from the measuring unit case ₇₂ to introduce air, so that the air introduction pipe 23 can be easily routed.

[Other embodiments]
The present invention can also be implemented in the following forms.

(1) A dehumidifying filter may be provided, and the air from which moisture has been removed by this dehumidifying filter may be supplied to the other end 23b of the air inlet pipe 23.

(2) The connection pipes are not limited to pipes through which drive cables or signal cables are inserted, and other connection pipes through which no cables are inserted may also be used.

(3) During weighing operation, the introduction of air through the air inlet pipe 23 to the weighing unit case 7 may be stopped so as not to affect the weighing by the load sensor 8, and air may be introduced through the air inlet pipe 23 to the weighing unit case 7 during periods when operation is stopped.

1 Weighing conveyor 3 Load measuring unit 5, _{5 1} , 5 ₂ Control box (housing for control unit)
7, _{7 1} , 7 ₂ Metering unit case (casing for measuring section)
8 Load sensor 21 First connecting pipe 22 Second connecting pipe 22 _First connecting pipe 23 Air inlet pipe 24 Branch connector 25 Cable gland 26 Filter regulator (air pressure adjustment device)
32 Exhaust pipe

Claims (8)

A weighing device including a weighing unit housing that houses a load sensor for detecting the weight of an object to be weighed conveyed by a conveyor,
An air introduction pipe is provided inside the housing for the measuring unit,
One end of the air introduction pipe is an end on an air discharge side having a diameter smaller than a diameter of a discharge pipe communicating with the casing for the measuring unit, and is inserted into the discharge pipe.
A weighing device characterized by: a control unit housing that houses a control unit that controls the driving of the conveyor, the weighing unit housing and the control unit housing being connected in communication with each other through a connecting pipe;
The end of the air introduction pipe on the air discharge side is inserted into a part of the connection pipe as the discharge pipe.
2. The weighing device of claim 1. At least two of the connecting pipes are provided,
The end of the air introduction pipe on the air discharge side is inserted into a part of at least one of the connection pipes as the discharge pipe.
3. A weighing device according to claim 2. an end portion of the air introduction pipe on the air discharge side is inserted into a part of one of the two connecting pipes from inside the housing for the measuring unit;
the air introduction pipe is inserted through the other of the two connection pipes from the metering unit housing to the control unit housing, and the other end of the air introduction pipe is drawn out to the outside of the control unit housing,
The other end of the air inlet pipe drawn out to the outside of the control unit housing is an air inlet end.
4. A weighing device according to claim 3. the one end of the air introduction pipe drawn into the inside of the casing for the measuring unit is branched into two branch end portions on the air discharge side, and each branch end portion is inserted into a portion of each of the two connecting pipes from the inside of the casing for the measuring unit,
The other end of the air introduction pipe is drawn out to the outside of the measuring unit housing,
The other end of the air introduction pipe drawn out to the outside of the casing for the measuring unit is an end on the air introduction side.
4. A weighing device according to claim 3. an end portion of the air introduction pipe on the air discharge side is inserted into a part of one of the two connecting pipes from inside the housing for the measuring unit;
The other end of the air introduction pipe is drawn out to the outside of the measuring unit housing,
The other end of the air introduction pipe drawn out to the outside of the casing for the measuring unit is an end on the air introduction side.
4. A weighing device according to claim 3. The other end of the air introduction pipe is led out to the outside of the casing for the measuring unit or the casing for the control unit via a cable gland.
A weighing device according to any one of claims 4 to 6. Air is introduced into the other end of the air introduction pipe via an air pressure adjustment device.
A weighing device according to any one of claims 4 to 7.

Images