JP2013194603A - Forced drainage pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a forced drainage pump which is easily retro-fitted to an existing drainage apparatus and capable of enhancing the flexibility of construction of a water section facility.SOLUTION: A side part space 55 is partitioned into a storage chamber 57 and an air chamber 59 by a partition member 56 in which the lower end edge is terminated at a position where an inner bottom face of a bottom part space 51 is not reached. On an outer wall of the storage chamber, an inflow nozzle is provided at least at one position and in the air chamber, an air pressure detection chamber 58A is formed which includes an air pressure detector and does not communicate with outside air. At a position lower than the air pressure detection chamber, an atmosphere communicating part 60 is provided which makes the air chamber communicate with the atmosphere, and an upper end portion of the atmosphere communicating part is positioned higher than the lower end edge of the partition member.

Description

  The present invention relates to a forced drainage pump for efficiently discharging filth, miscellaneous drainage, and other liquids around the water of a building such as a building or a house, and is particularly easy to be retrofitted to an existing facility, The present invention relates to a forced drainage pump that can increase the degree of freedom of construction of surrounding equipment.

  When designing and installing toilets, washrooms, kitchens, laundry areas, etc. installed in buildings such as buildings, houses, etc., create a gradient in the drain pipe (horizontal pipe) to be installed under the floor to reduce gravity. It is common to adopt a natural flow system that promotes the drainage that is used and transports it to an underground sewage tank via a collection pipe. However, in order to pipe a drainage pipe with a slope under the floor, it must be constructed within the height of the underfloor space of the frame or the height of the ceiling pocket. For this reason, the installation position of each drainage device such as a toilet bowl is subject to the restriction of the distance from the collecting standpipe. Alternatively, there is an inconvenience that it is necessary to secure a large space height in order to secure the height of the gradient of the drain pipe.

In addition, if the floor area of a building, etc. becomes larger and the water supply facilities diversify, the number of residential areas where the separation distance between the collecting pipe and the drainage device becomes longer will increase. Unless the height of the underfloor space and the height of the ceiling pocket are increased, it is difficult to secure the gradient from the drainage equipment. However, in recent designs of buildings and the like, there is a strong demand for reducing the space height as much as possible, making it difficult to match the demand for ensuring the slope of the drain pipe.
In order to deal with such problems, forced drainage pumps are connected to drainage pipes from toilets, sinks, sinks, washing machines, and other toilets installed in toilets, washrooms, kitchens, and laundry areas. In addition, it is effective to forcibly drain waste and miscellaneous wastewater through a horizontal piping path (Patent Document 1).

Japanese Patent Application Laid-Open No. 2004-151620 discloses a toilet having improved on-site workability by incorporating a pump for pumping and draining into the toilet itself in advance.
However, this pump for pumping and draining has a special structure in which the toilet and pump are unitized by placing the pump in close proximity in the space provided directly behind the bowl portion of the toilet and connecting it directly to the toilet. It cannot be applied to the construction of retrofitting to a dispatch drainage system by adding a pump to a toilet with a conventional structure. Moreover, since it is the structure which arrange | positions a storage tank and a pump in the slight space right behind back of the bowl part of a toilet bowl, only a small pump can be utilized and there exists a limit in the output obtained.

Moreover, since this pump is a direct connection type only for toilets, it is impossible to pump and discharge filth and miscellaneous wastewater from other drainage equipment to the collecting pipe using this pump.
In order to solve such a problem, Patent Document 2 discloses that the pump casing has a double body structure of an inner body part and an outer body part, and a space as an air reservoir is provided between both body parts. Is composed of a side space and an air chamber, detects changes in the water level in the air chamber as changes in the internal pressure of the air chamber, and turns on and off the pump using changes in the air chamber pressure caused by the inflow and discharge of wastewater from the outside. A forced drain pump that can be controlled is disclosed.

16 (a) and 16 (b) are a front view (A-B-B cross-sectional view of (b)) and a cross-sectional view ((a)) showing the main part of the forced drainage pump according to Patent Document 2 in cross section. XX sectional view).
This forced drainage pump is a means for efficiently discharging waste and miscellaneous wastewater from drainage equipment such as toilets, washstands, sinks, washing machines, etc., placed around the water of buildings, houses, etc. It is an on-floor installation type arranged between an inflow pipe and a drain pipe extending from a drainage device installed on the floor surface of a building or the like.
The forced drain pump includes a motor 200 having a vertical motor 200 with an output shaft 201 projecting from the bottom, an impeller 205 that rotates integrally with the output shaft by being fixed to the output shaft 201, and a motor unit. The pump casing 210 is connected to the inflow pipe 250 and the drain pipe 251 in a state where 204 is supported.
The pump casing 210 is disposed with a space 230 between a hollow cylindrical inner body portion 211 that supports the motor 200 in a watertight manner while the impeller 205 is housed therein, and a lower portion of the inner body portion 211. A large-diameter outer body 220, an inflow nozzle 221 and a drain nozzle 222 provided on the outer body 220 and connected to the inflow pipe and the drain pipe, respectively, and a vent hole 225 for communicating the space 230 with the atmosphere, Is provided.

The inner trunk portion 211 includes a volute portion 212 formed in a portion corresponding to the lower side from the outer diameter direction of the impeller so as to surround the impeller 205, and a volute suction port 213 formed in the lower center of the volute portion 212. , And the inside of the inner body portion communicates with the drainage nozzle 222. Furthermore, the inner trunk portion 211 includes a bearing portion (not shown) that rotatably supports the output shaft 201 of the motor.
The space 230 is formed between the inner bottom surface 220a of the outer body portion 220 and the lower portion of the volute portion 212, and communicates with the inflow nozzle 221. The space 230 communicates with the bottom space 231 on the outer diameter side of the volute portion. And a side space 235 formed so as to surround.
The side space 235 is partitioned by a partition member 236 into one storage chamber 237 provided on the inflow side and two air chambers 238 provided on the discharge side.
An inflow nozzle (inflow opening) 221 is provided on the outer wall of the storage chamber 237.

An air pressure detection port 240 communicating with an air pressure detector (not shown) is provided in the upper part of one air chamber 238. An air pressure detection chamber 241 that does not communicate with outside air extends upward from the air pressure detection port 240, and an air pressure detector is disposed in the air pressure detection chamber 241.
The start switch (pneumatic switch) of the motor 200 operates (turns on) when the air pressure detector detects that the air pressure in the air chamber 238 exceeds a predetermined specified value, and turns off when the air pressure falls below the specified value. It is configured as follows. When the drainage does not flow into the pump casing, the water level in the air chamber is lowered and the air pressure in the air chamber 238 is lower than the specified value, so the motor start switch does not operate and the motor is off. Is in a state. On the other hand, when the drainage flows into the pump casing and the water level in the air chamber 238 rises and the internal air pressure rises and exceeds the specified value, the air pressure detector is activated to turn on the start switch, and the motor Start up.

By the way, when the motor 200 is driven by the inflow of water from the inflow pipe 250 and the impeller 205 rotates, the water introduced from the inflow pipe is discharged to the drainage pipe 251 through the bottom space 231 and the volute 212. The pressure in the vicinity of the center of the impeller in the volute 212 is reduced (negative pressure) by the centrifugal force generated by the rotation of the impeller 205. This negative pressure also reduces the air pressure in the air chamber 238 via the volute inlet 213 and the space 231 during operation. That is, due to the negative pressure generated in the center of the impeller, the water level in the air chamber decreases and at the same time the pressure in the air chamber decreases. When the pressure in the air chamber falls below a predetermined value, the air pressure detector is turned off and the motor 200 is stopped. When suction by the pump is stopped by stopping the motor, the pressure in the air chamber returns (increases). At this time, when the inflow continues and the water level is equal to or higher than the predetermined value, the pressure in the air chamber rises to the predetermined value or higher, the motor restarts, and suction from the inflow pipe starts. Such an off / on cycle is repeated until there is no inflow, and the pump stops after the inflow has ceased. During the operation of a pump that originally requires continuous operation, the motor is turned off and on due to the negative pressure at the impeller center in a relatively short cycle, resulting in early damage to the equipment, unpleasant operating noise, and drainage. Problems such as reduced efficiency occur.
Further, when the remaining water level immediately after the pump stops after the inflow of water is equal to or higher than the lower edge of the partition member 236, the pressure in the air chamber is maintained at the negative pressure generated during the operation of the pump (the water level in the air chamber). May exceed the lower end 236a of the partition member 236), but in this state, even if there is an inflow again, the air pressure detector does not operate, so the motor does not start. In this case, the motor is started when a certain time elapses and the water level in the pump (the air level in the air chamber) becomes lower than the lower end edge of the partition member 236 and communicates with the atmosphere. Although improvement of such a motor malfunction has been conventionally demanded, it has not been solved.
If the pressure on the inflow piping side (indentation pressure) is sufficient, it will not be in a negative pressure state even if the pressure in the air chamber decreases, but the inflow side water supply device is normally in a state of pouring and there is almost no pressure. Even if the pressure increase (speed head) due to the flow velocity is taken into consideration, the suction pressure (Req.NPSH) of the impeller causes a negative pressure.

JP 2005-105581 A JP 2011-169078 A

The present invention has been made in view of the above, and efficiently disposes filth, miscellaneous drainage, and other fluids from drainage equipment such as toilets, washstands, sinks, and washing machines installed around the water in buildings and houses. An object of the present invention is to provide a forced drainage pump for discharging to the side, which is easy to be retrofitted to existing drainage equipment and can increase the degree of freedom of construction of watering equipment.
In particular, the negative pressure generated by the impeller rotated and driven by the motor can effectively eliminate the malfunction of the pump caused by lowering the air pressure in the air chamber equipped with the air pressure detector. It provides a forced drainage pump that can be used.

  In order to achieve the above object, a forced drain pump according to the invention of claim 1 is a forced drain pump disposed between an inflow pipe and a drain pipe, and includes a motor having an output shaft, and the output shaft. A motor unit including a fixed impeller, and a pump casing connected to the inflow pipe and the drain pipe while supporting the motor unit, and the pump casing includes the impeller inside. A hollow inner body portion that supports the motor in a housed state, and a lower portion of the inner body portion that is spaced apart from each other through a space and has a larger diameter than the inner body portion; and the outer body An inflow nozzle and a drainage nozzle that are connected to the inflow pipe and the drainage pipe, respectively, and a vent hole that communicates the space with the atmosphere, and the inner body portion corresponds to the impeller Volvo formed on , A volute suction port formed in a lower part of the volute part, and a discharge opening formed in a side wall of the volute part and communicating with the drain nozzle, and the space is an inner bottom surface of the outer trunk part And a bottom space formed between the lower portion of the volute portion and communicated with the inflow nozzle, and a side space formed on the outer diameter side of the volute portion and communicating with the bottom space. In the space, an air chamber is formed by a partition member that terminates at a position where the lower end edge does not reach the inner bottom surface of the bottom space, and the air chamber includes an air pressure detector and does not communicate with outside air. A chamber is formed in communication, and an air communication portion that communicates the air chamber with the atmosphere is provided at a position below the air pressure detection chamber, and an upper end portion of the air communication portion is a lower end of the partition member. Above the edge Characterized in that it is location.

The pump casing has a double body structure of an inner body part and an outer body part, and a space as an air reservoir is provided between both body parts. Further, the space includes a side space and an air chamber, and the motor can be controlled to be turned on and off by utilizing a change in internal pressure in the air chamber.
In addition, when negative pressure is generated in the impeller center due to the centrifugal force generated by the rotation of the impeller during operation of the motor, the fluid in the space and the air in the air chamber are sucked, so that the water level in the air chamber decreases. The pressure in the air chamber decreases. Since the height position of the air communication portion is above each height position of the lower edge of the partition member, the water level in the air chamber is lower than the air communication portion and the air chamber communicates with the atmosphere. The atmospheric pressure is released to atmospheric pressure.

The invention according to claim 2 is characterized in that the air communication portion is an air chamber vent hole formed through the side wall of the air chamber.
According to a third aspect of the present invention, the air chamber is divided into a first small chamber as an air pressure detection chamber and a second small chamber communicating with the atmosphere, and a lower end edge is located above the lower end edge of the partition member. An air pressure detection chamber is formed above the partition wall lower end edge of the first chamber, and the second chamber is air communicating with the atmosphere above the partition wall lower edge. A chamber communication hole is provided, and the first chamber and the second chamber are configured to communicate with each other when a water level in the air chamber falls below a lower end edge of the partition wall.

According to a fourth aspect of the present invention, there is a rising portion on the downstream side of the drainage pipe, and a check valve for backflow prevention is installed on the rising portion, the air chamber is connected to the downstream side of the check valve when the pump is stopped. It is characterized in that the water level in the air chamber in a state where there is a back pressure is arranged at an upper position not lower than the water level in the upstream side pipe of the check valve in the upward pipe at the same time.
On the downstream side of the drainage pipe, there is an upward pipe part that rises upward, and the upward pipe part is provided with a check valve that prohibits the rise of drainage or cancels the prohibition, It is characterized in that the water level in the air chamber when the check valve prohibits the rise of drainage is arranged at an upper position not lower than the water level in the upward pipe at the same time.

The invention according to claim 5 includes control means for controlling the motor, and the control means detects when the air pressure detector detects that the air pressure in the air chamber as the air pressure detection chamber exceeds a specified value. A drive command signal for driving the motor is output, and a drive stop command signal for stopping the motor drive is output when the air pressure detector detects that the air pressure has fallen below the specified value, and the control The means does not stop the motor immediately when the air pressure detector detects that the air pressure falls below a specified value during driving of the motor, but stops the motor after continuing the operation for a predetermined time. It is characterized by controlling to.
According to a sixth aspect of the present invention, when the air pressure detector detects that the air pressure exceeds a specified value during the operation of the motor for the predetermined time, the control means performs the predetermined operation. The timing of the remaining operation time is stopped, and the motor is newly operated for a predetermined time.

  According to the present invention, the negative pressure generated by the impeller that is rotationally driven by the motor effectively reduces the malfunction of the pump that occurs due to the decrease in the air pressure in the air chamber equipped with the air pressure detector. Can be resolved.

It is a front longitudinal cross-sectional view (AA sectional drawing of FIG. 3) which shows the structure of the forced drainage pump which concerns on one Embodiment of this invention. It is BB sectional drawing of FIG. It is a cross-sectional view of the forced drainage pump of the present invention. It is a top view which shows the piping state with respect to a forced drainage pump. (A) is principal part longitudinal cross-sectional view (AOB sectional drawing of (b)) which shows the characteristic structure of the forced drainage pump which concerns on one Embodiment of this invention, (b) is (a). It is XX sectional drawing of this, (c) is a block diagram which shows the structure of a control circuit. (A) And (b) is a principal part longitudinal cross-sectional view (AOBCD cross-sectional view of (b)) which shows the characteristic structure of the forced drainage pump which concerns on other embodiment of this invention. And (b) is an XX cross-sectional view of (a). It is a principal part longitudinal cross-sectional view (A-OBCD cross-sectional view of (b)) for demonstrating the influence of a negative pressure. It is a flowchart which shows an example of the control procedure of the forced drainage pump which concerns on this embodiment. (A) And (b) is a principal part longitudinal cross-sectional view (AOB sectional drawing of (b)) which shows the characteristic structure of the forced drainage pump which concerns on other embodiment of this invention, (b ) Is an XX cross-sectional view of (a). It is the figure which showed the external appearance structure of the forced drainage pump which concerns on embodiment of FIG. (A) And (b) is the top perspective view which shows the structural example of the pump casing used in common with the forced drainage pump which concerns on 2nd, 3rd embodiment, and a bottom perspective view. (A) is an external view of the drainage pump unit which accommodated the forced drainage pump of this invention in the decorative box, and the storage tank unit which accommodated the storage tank in the decorative box, (b) is the exploded view. (A) And (b) is installation state explanatory drawing which shows the state which connected the drainage pump unit to the drainage pipe of the toilet bowl. It is the schematic which shows the example which has arrange | positioned the drainage pump unit of this invention to the drainage equipment provided in various places of a house. It is a longitudinal cross-sectional view which shows the state which connected the storage tank and the drainage pump unit to the drainage apparatus sequentially. (A) And (b) is the front view (AOB sectional view of (b)) which shows the principal part of the forced drainage pump which concerns on patent document 2 in a cross section, and X-axis of (a) X sectional view).

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings.
FIG. 1 is a front longitudinal sectional view (sectional view taken along line AA in FIG. 3) showing a configuration of a forced drain pump according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along line BB in FIG. 3 is a cross-sectional view of the forced drain pump of the present invention, and FIG. 4 is a plan view showing a piping state with respect to the forced drain pump.

The forced drainage pump 1 according to the present invention efficiently removes filth, miscellaneous drainage, and other fluids from drainage equipment such as toilets, washstands, sinks, and washing machines arranged around the water of buildings such as buildings and houses. It is a means for discharging to the downstream side, and can be assembled by retrofitting or the like in a narrow space around the drainage device as will be described later. The illustrated configuration example is an on-floor installation type disposed between an inflow pipe 91 and a drain pipe 92 extending from a drainage device installed on a floor surface 90 of a building or the like. The installation location does not matter, such as the type to be buried. In this example, a vibration-proof rubber 93 is disposed on the floor surface 90 to absorb and reduce vibration and noise generated from the pump.
The forced drain pump 1 includes a motor unit having a vertical motor 2 in which an output shaft 2a projects from the lower part, and an impeller 3 that rotates integrally with the output shaft by fixing the shaft center part to the output shaft 2a. 4 and a pump casing 20 that is connected to the inflow pipe 91 and the drain pipe 92 in a state where the motor unit 4 is supported.

The pump casing 20 is disposed with a space 50 between a hollow cylindrical inner barrel portion 21 that supports the motor 2 in a watertight manner while the impeller 3 is accommodated therein, and a lower portion of the inner barrel portion 21. An outer body 40 having a diameter larger than that of the inner body, an inflow nozzle 41 and a drain nozzle 42 provided in the outer body 40 and connected to an inflow pipe and a drain pipe, respectively, and a space provided in the inflow nozzle. Ventilation hole 45 which makes 50 communicate with the atmosphere. The inner trunk portion 21 and the outer trunk portion 40 are integrated by, for example, integral molding.
The pump casing 20 of the present invention has a double body structure composed of an inner body part 21 and an outer body part 40, and is characterized by a structure in which a space 50 is formed between the inner body part 21 and the outer body part 40. It is. As will be described later, in this embodiment, the center portion C1 of the substantially cylindrical inner trunk portion 21 and the center portion C2 of the substantially cylindrical outer trunk portion 40 do not coincide with each other. Good.

The inner body portion 21 includes a volute portion 25 formed in a portion corresponding to the lower side from the outer diameter direction of the impeller so as to surround the impeller 3, and a volute suction port 26 formed in the lower center of the volute portion 25. And a discharge opening 27 a formed in the volute side wall 27 and communicating with the drain nozzle 42. Furthermore, the inner body portion 21 includes a shaft seal portion 30 that prevents leakage of water to the outside, and an oil reservoir 31 that stores the lubricating oil 32 supplied to the shaft seal portion 30.
The space 50 is formed between the inner bottom surface 40a of the outer body portion 40 and the lower portion of the volute portion, and communicates with the inflow nozzle 41, and communicates with the bottom space 51 on the outer diameter side of the volute portion. And a side space 55 formed so as to surround it.
The side space 55 is partitioned by two partition members 56 into one storage chamber 57 provided on the inflow side and two air chambers (air pressure detection chambers) 58 provided on the discharge side. The partition member 56 terminates at a position where the lower end edge 56 a does not reach the inner bottom surface of the bottom space 51. That is, the storage chamber 57 and the air chamber 58 are arranged in the circumferential direction with the partition member 56 interposed therebetween, but communicate with each other through the bottom space 51.
At least one inflow nozzle (inflow opening) 41 is provided on the outer wall of the storage chamber 57.

In the upper part of the air chamber 58, an air pressure detection port 59a communicating with the air pressure detector is provided. Above the air pressure detection port 59a, an air pressure detection chamber 59 that does not communicate with outside air extends upward, and an air pressure detector is disposed in the air pressure detection chamber 59.
That is, an air pressure detection chamber 59 that includes an air pressure detector and does not communicate with the outside air is formed in communication with the upper portion of the air chamber 58, and the air chamber is located below the air pressure detection chamber (air pressure detection port). An air communication part that communicates with the atmosphere is provided.
Since the air pressure detection port 59a communicates with an air pressure detector (not shown), the air pressure in the air chamber 58 decreases when the pump is stopped and the drainage in the volute portion is reduced. Then stop the pump.

The partition member 56 functions as a shielding member for reducing the influence of a large amount of inflow from the inflow nozzle 41 and strong water (dynamic pressure) on the air pressure detector disposed in the inner part of the air chamber. That is, the partition member 56 is configured so that the inflow amount and the water flow during the operation of the motor do not affect the detection accuracy of the air pressure detector.
When the amount of drainage in the volute is below a predetermined value, the resistance against the rotation of the impeller decreases, so that the decrease in resistance is electrically detected and the power supply to the motor is turned off. May be.

Under the control of the control means, the start switch (pneumatic switch) of the motor 2 is activated (turned on) when the air pressure detector detects that the air pressure in the air chamber 58 exceeds a predetermined specified value, and sets the specified value. It is configured to turn off when below. When the drainage from the drainage device does not flow into the pump casing, the air pressure in the air chamber 58 is lower than the specified value, so the motor start switch does not operate and the motor is in the off state. . On the other hand, when the air pressure in the air chamber 58 rises and exceeds the specified value due to the drainage from the drainage device flowing into the pump casing, the air pressure detector is activated and the start switch is turned on to start the motor Let
That is, the air chamber 58 functions as an air pressure holding source of the start switch for automatically operating the motor. By providing the air pressure detection port 59a on the ceiling (upper part) of the air chamber 58, an unillustrated start switch connecting pipe Prevent sewage from entering. The reason for not using the liquid contact type sensor is to avoid a malfunction due to adhesion of dirt.

The automatic operation on / off water level of the pump is as shown in FIG. 2, and the off water level is the volute inlet water level (air suction state) in order to prevent the occurrence of scum.
By setting the height level (water level when the pump is OFF) h1 of the volute suction port 26 to be lower than the height level h2 of the opening lower edge 41a of the inflow nozzle 41, the water in the bottom space 51 when the pump is stopped Can flow back to the inflow nozzle side (residual water in the inflow piping).
By providing a through hole 25a communicating with the storage chamber 57 in the uppermost portion of the volute 25, that is, on the wall surface of the volute positioned in the outer diameter direction of the outer peripheral surface of the impeller 3, air accumulated in the volute is stored in the storage chamber. It becomes possible to discharge to the atmosphere via the vent hole 45 via 57. That is, when the discharge check valve for preventing the backflow provided in the drain pipe 92 is “closed” (while the pump is stopped), the air accumulated in the volute portion is vented to the vent hole 45 through the through hole 25a. Since it comprised as mentioned above, inflow of the waste_water | drain from the inflow piping 91 is performed smoothly.

Next, Fig.5 (a) is a principal part longitudinal cross-sectional view (AOB sectional drawing of (b)) which shows the characteristic structure of the forced drainage pump which concerns on one Embodiment of this invention, (b) ) Is a sectional view taken along line XX in (a), and (c) is a block diagram showing a configuration of a control circuit.
The forced drain pump 1 according to the present embodiment includes an air pressure detector S and communicates an air chamber (air pressure detection chamber) 58 with outside air at a position below the air pressure detection port 59a of the air pressure detection chamber 59 that does not communicate with outside air. It is characteristic that a dedicated air chamber ventilation hole (atmospheric communication portion) 60 is provided. The air chamber vent 60 communicates with a vent pipe 60A that communicates with the atmosphere.
That is, in this example, the air chamber vent hole 60 is formed in the air chamber side wall 61, and the upper end portion 60 a of the air chamber vent hole 60 (the lower end portion of the side wall 61) is higher than the lower end edge 56 a of the partition member 56. To be in position. As a result, the water level in the air chamber decreases and falls below the air chamber vent upper end edge 60a, and at the same time, the air chamber is released to the atmosphere and can be returned to the initial state (the state before the motor 2 is started).
That is, before starting the motor, the water level in the pump is low and is below the upper edge 60a of the air chamber vent, so the air chamber 58 is opened to the atmosphere via the air chamber vent 60 and the vent pipe 60A. The
The upper end 60 a of the air chamber vent is positioned above the lower end of the volute 25, that is, the volute suction port 26.

The drainage flows into the space 50 from the outside via the inflow pipe 91, the air chamber water level starts to rise, rises over the upper end portion 60a of the air chamber vent, and the air chamber pressure exceeds the specified value. Then, the air pressure detector S detects this and transmits a detection signal to the control means (CPU and others), so that the control means transmits a control signal to the motor 2 to start driving.
When the inflow of drainage stops and the water level in the air chamber falls below the air chamber vent upper end edge 60a, the air chamber 58 and the vent pipe 60A are in communication with each other. When the pressure detector S detects this and transmits a detection signal to the control means, the control means transmits a control signal to the motor 2 to stop driving.

By the way, in this embodiment, when a negative pressure is generated in the center of the impeller due to the centrifugal force generated by the rotation of the impeller 3 during the operation of the motor, the water between the volute suction port 26 and the air chamber 58 is caused by the negative pressure. Since the air in the air chamber is sucked, the water level in the air chamber decreases and the pressure in the air chamber decreases. Since the height position of the air chamber vent hole upper edge 60a is higher than the height positions of the volute suction port 26 and the partition member lower edge 56a, the water level in the air chamber is higher than the air chamber vent upper edge 60a. When the air chamber and the vent pipe 60A communicate with each other below the air pressure, the air pressure in the air chamber is released to atmospheric pressure.
When the air chamber vent hole 60 is not present, the negative pressure generated in the center of the impeller during operation of the motor causes the pressure in the air chamber to drop below a predetermined value, and the air pressure detector is turned off. 2 is stopped. At this time, a part of the air in the air chamber is sucked and discharged by the negative pressure generated in the center of the impeller during operation of the motor, so that the negative pressure is easily maintained in the air chamber even after the motor stops. The water level in the air chamber is higher than the lower edge of the partition member. Thus, in a state where the air chamber is maintained at a negative pressure, even if water flows in again, the air pressure detector does not turn on and the motor does not start.
On the other hand, in this embodiment, even if the water level in the air chamber is above the lower end edge of the partition member, the air chamber can be communicated with the atmosphere as long as it is below the upper end edge 60a of the air chamber vent hole 60. Therefore, the negative pressure in the air chamber can be eliminated, and the air pressure detector can be reliably turned on and the motor can be started when water newly enters.

Next, FIGS. 6 (a) and 6 (b) are longitudinal cross-sectional views of the main part showing the characteristic configuration of the forced drainage pump according to another embodiment of the present invention (A-O-B-C- in (b)). (D sectional drawing), (b) is XX sectional drawing of (a). FIG. 7 is a vertical cross-sectional view of an essential part for explaining the influence of the negative pressure (A-O-B-C-D cross-sectional view of (b)). The same parts as those in FIGS. 1 to 5 are denoted by the same reference numerals. Moreover, FIG. 8 is a flowchart which shows an example of the control procedure of the forced drainage pump which concerns on this embodiment.
In the forced drainage pump 1 according to the present embodiment, the air chamber 58 formed by partitioning the side space 55 by the partition member 56 is replaced with the first small chamber (air pressure detection chamber) 63 for air pressure detection by the partition wall 62. In addition to partitioning into a second small chamber (venting chamber) 64 communicating with the atmosphere, the lower end edge 62 a of the partition wall 62 is positioned above the lower end edge 56 a of the partition member 56. The first small chamber 63 does not communicate with the outside air except for a lower open portion (atmospheric communication portion) that communicates with the bottom space 51.

In this example, the position where the partition member 56 is formed is different from the partition member of FIG. That is, in the present embodiment, the partition member 56 is provided in the side space 55 near the inflow nozzle 41, thereby forming one air chamber 58 on one side of the partition member 56 and further provided in the air chamber 58. The partition wall 62 divides the air chamber 58 into a first small chamber 63 and a second small chamber 64. In addition, each lower end edge of the partition member 56 and the partition wall 62 is terminated at a position that does not reach the inner bottom surface 40a of the outer trunk portion.
In addition, the position of the partition member lower end edge 56a is not limited to the illustrated height position, and may be lower than the lower end edge 62a of the partition wall.
Further, an air pressure detection port 65a is formed above the partition wall lower end edge 62a of the first small chamber, and the air in communication with the atmosphere is disposed above the partition wall lower end edge 62a of the second chamber 64. A chamber communication hole 66 is formed. Above the air pressure detection port 65a, an air pressure detection chamber 65 that does not communicate with outside air extends upward, and an air pressure detector is disposed in the air pressure detection chamber 65.
The first small chamber 63 and the second small chamber 64 can communicate with each other via the side space 55 (or the bottom space 51) (atmospheric communication portion) located below the partition wall lower edge 62a. The chamber 58 (63, 64) is configured to communicate with the water level when it falls below the partition wall lower edge 62a.

In the embodiment of FIG. 5, when the air chamber vent 60 is sideways and the opening diameter is small, it cannot be said that there is no risk of foreign matter adhering and sedimenting there and blocking over time.
On the other hand, in the embodiment of FIG. 6, such a problem can be prevented in advance because the air chamber side holes are not provided with air chamber vents that are likely to be clogged with foreign matter.
That is, the lower part of the first small chamber 63 and the second small chamber 64 is an open portion (atmospheric communication portion) communicating with the side space 55, and the partition wall lower edge 62 a and the inner bottom surface 40 a of the bottom space 51 are formed. Since there is a sufficient space between the two, there is no possibility that foreign matter adheres, settles and is blocked.

Further, as in the case of the embodiment of FIG. 5, the height position of the partition wall lower edge 62a is arranged above the partition member lower edge 56a, so that the water level in the air chamber exceeds the partition member lower edge 56a. However, if it is below the partition wall lower edge 62a, the first small chamber 63 can be communicated with the atmosphere, so that the negative pressure in the first small chamber 63 can be eliminated, and new inflow of water can be achieved. When this happens, the air pressure detector can be reliably turned on to start the motor (state shown in FIG. 7).
That is, before the start of the motor, the water level in the pump is low and the position is below the partition wall lower edge 62a, so the first small chamber 63 is opened to the atmosphere.
The drainage flows into the space 50 from the outside via the inflow pipe 91, the air chamber water level starts to rise, rises beyond the partition wall lower edge 62a, and the first small chamber pressure becomes equal to or higher than the specified value. Then, when the air pressure detector detects this and transmits a detection signal to the control means, the control means transmits a control signal (drive command signal) to the motor 2 to start driving.

When the inflow of drainage stops, the water level in the first small chamber 63 falls below the partition wall lower edge 62a, so that the first small chamber 63 and the second small chamber 64 are in communication with each other. When the pressure falls below a specified value, the air pressure detector detects this and sends a detection signal (off signal) to the control means, so that the control means sends a control signal (drive stop command signal) to the motor 2. To stop driving.
If the flow rate from the inflow nozzle 41 is sufficient as shown by the two-dot chain line in FIG. 7 with respect to the flow rate discharged from the drain nozzle 42 during operation of the motor, the water level in the pipe of the inflow nozzle The air hole 45 does not function because it does not decrease.

Next, the control means does not stop the motor immediately when the pneumatic detector outputs an off signal, but forcibly continues the operation for a predetermined time (t), for example, about 10 seconds, and then stops the operation. (FIG. 8, steps S1 to S5). By controlling in this way, the pressure in the air chamber decreases due to the negative pressure generated at the impeller center during operation of the motor, and it can be prevented that the pump stops even though the inflow continues. The motor can be stopped when the water level of the first small chamber 63 is stabilized in a state where it is reliably below the lower end edge 62a of the partition wall.
However, if the water level rises again during forced operation of the motor and the pneumatic detector sends an ON signal, the remaining operation time is stopped and a new count is started (operation continues S6, 8, 9). Then, after the operation is continued for a new fixed time, the motor is controlled to stop. This control is continued until the water level in the first small chamber becomes equal to or less than the specified value (below the partition wall lower edge 62a) and the first small chamber and the second small chamber are in communication.

If controlled in this way, even if the air pressure detector sends off once during the forced operation of the motor, if the large flow of water continues to flow in, the motor is continuously operated. The water level in the first small chamber can be set to a specified value or less, and the pneumatic detector can be finally turned off. For this reason, it is possible to prevent the first small chamber 63 from becoming negative pressure and to immediately operate the air pressure detector when there is a new inflow.
The control method described in FIG. 8 can be applied not only to the embodiment of FIG. 5 but also to other embodiments described later.
In FIG. 6, the first small chamber 63 on the inner diameter side is an air pressure detection chamber and the second small chamber 64 on the outer diameter side is an air communication chamber, but this may be reversed.
Next, when there is a vertical pipe on the downstream side of the pump, the water in the pipe up to the downstream check valve flows backward after the pump is stopped and stays as residual water in the pump. When the amount of remaining water is large, the water level in the pump becomes high, and even if the inflow and drainage are finished, a problem occurs that the pneumatic pressure detector transmits an ON signal to drive the motor.
Moreover, even if there is little residual water, the water level in a pump may rise temporarily by the water force at the time of a reverse flow, and an ON signal may be transmitted. For this reason, even if the inflow and discharge into the pump are completed, a malfunction in which the motor repeatedly turns on and off is likely to occur.

The embodiment of FIG. 9 is for solving the above problems.
9 (a) and 9 (b) are longitudinal cross-sectional views (A-B-B cross-sectional view of (b)) showing a characteristic configuration of a forced drainage pump according to another embodiment of the present invention. And (b) is an XX cross-sectional view of (a). The same parts as those in FIGS. 1 to 5 are denoted by the same reference numerals.
In the forced drainage pump 1 according to the present embodiment, there is an upward piping portion 92a that rises upward on the downstream side of the drainage piping 92, and the upward piping portion 92a prohibits (limits) or releases the prohibition of the drainage ( A check valve 92b is provided to block water flow in the upward piping section. In the air chamber, the water level in the air chamber (pneumatic pressure detection chamber) 58 in a state where back pressure is present in the downstream pipe of the check valve when the pump is stopped similarly controls the water level in the upward pipe 92a when the rise of drainage is prohibited. It is arranged in an upper position that does not fall below.

In the present embodiment, the air level in the air chamber (air pressure detection chamber) 58 when the check valve prohibits the rise of drainage is determined as the air chamber 58 formed by partitioning the side space 55 by the partition member 56. Similarly, when the drainage is prohibited from rising, it is disposed at an upper position not lower than the highest rising water level in the upward pipe 92a.
Specifically, it is fixed in a state where the lower end portion of the tubular air chamber 58 extending upward is communicated with the opening 58 a provided on the ceiling surface of the side space 55, and is further attached to the side wall of the air chamber 58. An L-shaped vent pipe 67 is connected to the provided through hole (atmospheric communication portion) 58b. The ventilation pipe 67 includes a horizontal pipe 67a extending in the horizontal direction and a vertical pipe 67b extending upward from the distal end portion of the horizontal pipe, and communicates with the atmosphere.

In this example, the partition member lower edge 56a is located at the same position as the ceiling surface of the side space 55, while the upper end portion of the through hole 58b serving as the air communication portion is located above the partition member lower edge 56a. . Moreover, the height position of the through hole 58b is arranged at a position that does not fall below the maximum water level in the upward pipe 92a when the check valve 92b prohibits the rise of drainage.
Note that the water levels indicated by WL1 and WL2 in FIG. 9A are the air chamber 58 and the vent pipe corresponding to the maximum water level in the upward pipe 92a when the check valve 92b prohibits the rise of drainage. 67 is the water level. Moreover, the water level shown by WL3 has shown the water level reduced by completion | finish of drainage.
There is an air pressure detection chamber 58A that does not communicate with the atmosphere above the inside of the air chamber 58, that is, above the through hole 58b, and an air pressure detector is disposed in the air pressure detection chamber.
In this example, an air pressure detector is disposed in the air pressure detection chamber 58A that linearly extends upward from the air chamber 58, and the vent pipe 67 that branches and extends in an L shape is used for air communication. It may be reversed.

The operation process of the forced drainage pump 1 according to the present embodiment is as follows.
First, before the motor is started (initial state), the water level of the remaining water is at the position WL3 and is lower than the through hole 58b. Therefore, the air pressure detection disposed in the air pressure detection chamber 58A extending above the air chamber 58 is detected. The vessel is in the off state.
It is necessary to set the height position of the through hole 58b (branch portion) as the atmosphere communication portion after adjusting the height position so as to be optimal according to the difference in the height position of the check valve. That is, the remaining water level WL3 when the motor is stopped varies depending on the height position of the check valve and the remaining water amount, that is, the piping distance (pipe diameter) between the check valve and the pump. After taking into account, the height position of the air communication part is determined. Alternatively, the height position of the check valve and the piping distance may be made constant while keeping the height position of the atmosphere communication portion constant.

Next, when drainage flows from the outside into the pump, the water level in the air chamber 58 rises, and when the water level rises beyond the branch position, that is, the upper end of the through hole 58b, the pressure in the air pressure detection chamber 58A rises. When the pressure exceeds the specified value, the air pressure detector transmits an ON signal to the control means, and the control means starts the motor.
When there is a large amount of inflow at a time, such as a toilet, the water level rapidly rises due to the water force, so the motor starts simultaneously with the inflow.
When drainage is completed, the water level in the air pressure detection chamber decreases, and when the water level becomes lower than the upper end of the through hole 58b, the air pressure detection chamber 58A is opened to the atmosphere, and the air pressure detector outputs an off signal. Stop.

  The pipes connected to the forced drain pump 1 having the above-described configuration need to be provided with a gradient in the drainage pipe on the downstream side by arranging the excess space on the floor surface around the drainage equipment such as a toilet. And the frequency of drainage clogging is greatly reduced. In addition, there is an advantage that maintenance of the exposed motor and the piping portion is facilitated. Moreover, it is easy to install this motor by retrofitting with respect to water around existing buildings, residences, etc., and drainage efficiency in the water around can be enhanced.

Further, the forced drainage pump 1 is characterized in that the axial center portion C1 of the volute portion 25 is arranged so as to be displaced toward the drainage nozzle side (left side of the drawing) with respect to the center portion C2 of the outer trunk portion. . By configuring in this way, it becomes possible to secure the volume of the storage chamber 57 constituting the side space 55 larger than the volume of the air chamber 58, and as a result of increasing the area of the outer wall of the storage chamber, a plurality of It becomes possible to arrange the inflow nozzle 41 at different locations on the outer wall of the storage chamber. By providing a plurality of inflow nozzles, it becomes possible to connect pipe bodies that flexibly correspond to the difference in the positional relationship between the discharge pipe (inflow pipe) of the drainage device and the discharge pipe. In addition, by providing multiple inflow nozzles on the outer periphery of the outer body, it is possible to collect the drainage from various drainage equipment in one place, and it is possible to construct the pipes in the shortest time, corresponding to the installation direction of the drainage equipment It becomes.
Further, since the protrusion amount of the outer body portion toward the outflow nozzle side where the air chamber 58 is present is reduced, the outer diameter of the outer body portion can be minimized as a whole, and the entire pump can be reduced in size.

When a plurality of inflow nozzles 41 are not disposed, that is, when only one inflow nozzle is disposed, the axial center portion C1 of the volute 25 is disposed on the drain nozzle side (on the left side in the drawing) with respect to the center portion C2 of the outer trunk portion ) Is not required to be offset.
In the present invention, since the heights of the ceiling surfaces of the inflow nozzle 41 (inflow pipe 91) and the drainage nozzle 42 (discharge pipe 102) are matched, air does not collect on the upper part of any nozzle when the pump is driven. . Therefore, there is no possibility that the air accumulated in any of the nozzles moves to the impeller side and causes an air lock or the like.
Since the impeller 3 is positioned below the ceiling surface of the inflow nozzle 41 (inflow pipe 91) and the drain nozzle 42 (discharge pipe 102), air does not collect around the impeller.
Since the height position of the bottom surface 3a of the outer peripheral portion of the impeller 3 is set to the same height as the bottom surface of the through hole 25a or lower than the bottom surface of the through hole, waste water containing foreign matter enters the through hole 25a. It is possible to eliminate problems such as clogging caused by closing the cover.

Next, FIG. 10 is a diagram showing an external configuration of the forced drainage pump according to the embodiment of FIG. 9, and FIGS. 11 (a) and 11 (b) are forcings according to the embodiment of FIG. 9 and the embodiment of FIG. It is the top perspective view which shows the structural example of the pump casing used in common with a drainage pump, and a bottom perspective view.
In this forced drainage pump 1, the motor 2 and the pump casing 20 can be used in common in the above two embodiments, and the first, second, and third holes 71, 72, 73 is formed.
The third hole 73 is a part for detachably mounting the lower end opening 58a of the tubular air chamber 58 in the embodiment of FIG. At this time, the other holes 71 and 72 that are not used are closed with a closing plug or the like.
The first hole 71 and the second hole 72 are used in the embodiment of FIG. That is, the second hole 72 is a part that detachably connects the lower end of the annular air detection chamber 65 in the embodiment of FIG. 6, and the first hole 71 corresponds to the air chamber communication hole 66. At this time, the unused third hole 73 is closed. In the bottom view of FIG. 11B, the arc-shaped protrusion 75 located between the first hole 71 and the second hole 72 is the partition wall 62 of the embodiment of FIG.

Next, FIG. 12 (a) is an external view of a drainage pump unit in which the forced drainage pump of the present invention is accommodated in a cosmetic box, and a storage tank unit in which a storage tank is accommodated in the cosmetic box. FIG. Is an exploded view thereof. 13 (a) and 13 (b) are explanatory views of the installation state showing the state in which the drainage pump unit is connected to the drainage pipe of the toilet bowl, and FIG. It is the schematic which shows the example which has arrange | positioned. FIG. 15 is a longitudinal sectional view showing a state in which a storage tank and a drainage pump unit are sequentially connected to the drainage device.
The forced drainage pump 1 of the present invention is constructed in a cosmetic box 100 as shown in FIG. 12 to construct a drainage pump unit 105, and this drainage pump unit 105 is installed in a floor space around a drainage device 120 such as a toilet. To do. In addition, a storage tank 110 may be connected to the upstream side of the drainage pump unit 105 (between the drainage device and the forced drainage pump).
The storage tank 110 has an inflow side connection portion connected to the drain pipe of the drainage device 120 on the front surface, and an outflow side connection portion connected to the inflow pipe on the drain pump unit 105 side on the side surface.

By making the opposing surfaces of the rectangular parallelepiped decorative box 100 and the rectangular parallelepiped storage tank 110 into the same shape that match each other, when they are combined, it can be configured as a thin rectangular parallelepiped as shown in FIG. It becomes possible to arrange in a narrow space around the toilet bowl or the like.
The storage tank 110 is disposed between the drainage device 120 and the forced drainage pump and temporarily drains the drainage device when the amount of drainage from the drainage device 120 may exceed the capacity of the forced drainage pump 1. And is used to limit the amount of time drainage to the forced drain pump 1. Therefore, the storage tank 110 is unnecessary when the amount of time drainage from the drainage device does not exceed the capacity of the forced drainage pump 1.

In the example of FIG. 13, an example in which the drainage pump unit 105 and the storage tank 110 are arranged using a space that is normally formed behind the toilet 120 is illustrated. According to this, floor / ceiling exposed piping or concealment piping is possible in a place where the drainage gradient cannot be obtained, and installation can be completed in a short time. Also, the removal work is easy. When clogging occurs due to contamination by foreign matter, it is possible to remove or replace the foreign matter by separating only the pump unit. Even in the case of using a small pipe (25 mm), the water brush effect and the scale clogging prevention effect due to the powerful drainage effect utilizing the suction force of the pump can be exhibited. Since the amount of water used for flushing toilet bowls can be reduced, the flush tank can be downsized. Furthermore, a sewage pit is not required.
The forced drainage pump 1 of the present invention is, for example, drainage treatment in a basement, renovation of kitchens and toilets, drainage pipe work accompanying renovation of stores and tenants, new installation of watering equipment for nursing care, filthy logistics sites in hospitals, extension It is very effective when installing temporary toilets such as water facilities at the time of expansion, employees at construction sites and event venues.
At this time, since a plurality of pipes can be connected to the forced drain pump 1, the degree of freedom in layout increases and the reservoir can be easily connected. Specifically, for example, the storage tank 110 is disposed behind the toilet 120 as in the forced drainage system shown in FIGS. 13A and 13B, and forced drainage is performed on either side of the storage tank 110. An L-shaped connection to which the pump 1 is connected, or an I-shaped connection in which the toilet 120, the storage tank 110, and the forced drainage pump 1 are connected in a straight line as shown in FIG.
By attaching a plurality of inflow nozzles to the storage tank 110 as shown in FIG.

As described above, in the forced drainage system according to the present invention, since a pipe from another drainage device is connected to a storage tank or a forced drainage pump arranged in the immediate vicinity of one drainage device such as a toilet, one forced drainage pump The drainage from a plurality of drainage devices can be discharged to a common drainage pipe 92 by using the output of.
The forced drainage pump or forced drainage system of the present invention can be used, for example, in a tenant building, when there is a need to install a sudden water supply in a renovation accompanying a tenant replacement, Drainage equipment can be installed without considering the positional relationship with the vertical pipe.
The present invention can be used not only for wastewater but also for draining any fluid.

  DESCRIPTION OF SYMBOLS 1 ... Forced drainage pump, 2 ... Motor, 2a ... Output shaft, 3 ... Impeller, 3a ... Bottom surface, 4 ... Motor unit, 20 ... Pump casing, 21 ... Inner body part, 25 ... Volute part, 25a ... Through-hole, 27: Volute side wall, 27a: Discharge opening, 30 ... Shaft seal, 32 ... Lubricating oil, 40 ... Outer body, 40a ... Inner bottom surface, 41 ... Inflow nozzle, 41a ... Lower end edge of opening, 42 ... Drain nozzle, 42 DESCRIPTION OF SYMBOLS ... Drain nozzle, 45 ... Vent, 50 ... Space, 51 ... Bottom space, 55 ... Side space, 56 ... Partition member, 56a ... Bottom edge of partition member, 57 ... Storage chamber, 58 ... Air chamber, 58A ... Air pressure detection 58a ... Opening, 58b ... Through hole, 59 ... Pneumatic detection chamber, 59a ... Pneumatic detection port, 60 ... Air chamber vent, 60A ... Vent pipe, 60a ... Air chamber vent upper end edge, 61 ... Side wall, 62 ... partition wall, 62a ... partition wall Edge 63, 1st chamber, 64 ... 2nd chamber, 65 ... Air pressure detection chamber, 65a ... Air pressure detection port, 66 ... Air chamber communication hole, 67 ... Vent tube, 67a ... Horizontal tube, 67b ... Vertical Pipe 90, floor, 91, inflow pipe, 92 ... drain pipe, 92a ... pipe, 92b ... check valve, 93 ... anti-vibration rubber, 100 ... decorative box, 102 ... discharge pipe, 105 ... drain pump unit, 110 ... Storage tank, 111 ... inflow side connection part, 112 ... outflow side connection part, 120 ... drainage equipment.

Claims (6)

A forced drain pump arranged between the inflow pipe and the drain pipe,
A motor having an output shaft, and a motor unit having an impeller fixed to the output shaft;
A pump casing connected in communication with the inflow pipe and the drain pipe in a state where the motor unit is supported,
The pump casing is disposed with a space between a hollow inner trunk portion that supports the motor in a state where the impeller is housed therein and a lower portion of the inner trunk portion, with a space therebetween. A large-diameter outer trunk, an inflow nozzle and a drain nozzle provided in the outer trunk and connected to the inflow pipe and the drain pipe, respectively, and a vent hole for communicating the space with the atmosphere,
The inner body portion includes a volute portion formed in a portion corresponding to the impeller, a volute suction port formed in a lower portion of the volute portion, and a discharge formed in a side wall of the volute portion and communicating with the drain nozzle. An opening, and
The space is formed between an inner bottom surface of the outer body portion and a lower portion of the volute portion, and is formed on the outer diameter side of the volute portion, communicating with the bottom space, communicating with the inflow nozzle. A side space,
In the side space, an air chamber is formed by a partition member terminating at a position where the lower end edge does not reach the inner bottom surface of the bottom space,
The air chamber is provided with an air pressure detection chamber that includes an air pressure detector and does not communicate with the outside air.
At a position below the air pressure detection chamber, an air communication portion that connects the air chamber to the atmosphere is provided,
The forced drainage pump according to claim 1, wherein an upper end portion of the atmosphere communication portion is positioned above a lower end edge of the partition member.   The forced drainage pump according to claim 1, wherein the air communication part is an air chamber vent formed through the side wall of the air chamber. A partition wall in which the air chamber is partitioned into a first chamber serving as an air pressure detection chamber and a second chamber communicating with the atmosphere, and a lower end edge is positioned above a lower end edge of the partition member;
The air pressure detection chamber is formed above the lower edge of the partition wall of the first small chamber,
The second small chamber includes a communication hole for an air chamber that communicates with the atmosphere above the lower end edge of the partition wall,
2. The forced drainage according to claim 1, wherein the first chamber and the second chamber are configured to communicate with each other when a water level in the air chamber falls below a lower end edge of the partition wall. pump. There is an upward piping section that rises upward on the downstream side of the drainage pipe, and the upward piping section is provided with a check valve that prohibits the rise of drainage or cancels the prohibition,
The air chamber is in an upper position where the water level in the air chamber when back pressure is in the downstream side of the check valve when the pump is stopped does not fall below the water level in the upstream side of the check valve in the upward piping at the same time. The forced drainage pump according to claim 1, wherein the forced drainage pump is arranged. Control means for controlling the motor,
The control means outputs a drive command signal for driving the motor when the air pressure detector detects that the air pressure in the air chamber serving as the air pressure detection chamber exceeds a specified value, and the air pressure is determined by the specified air pressure. A drive stop command signal for stopping the drive of the motor when the air pressure detector detects that the value is below the value,
The control means does not stop the motor immediately when the air pressure detector detects that the air pressure has fallen below a specified value while driving the motor, but stops after the operation is continued for a predetermined time. The forced drainage pump according to any one of claims 1 to 4, wherein the forced drainage pump is controlled to be controlled.   When the air pressure detector detects that the air pressure has exceeded a specified value while the motor is continuously operating for the predetermined time, the control means determines the remaining operating time of the predetermined time. 6. The forced drain pump according to claim 5, wherein the time counting is stopped and the motor is newly operated for a predetermined time.

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