JP3366876B2 - Rotary pump - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary pump suitable for transporting liquid food, and more particularly to a cleaning structure for a pump chamber of the rotary pump.

[0002]

2. Description of the Related Art In a rotary pump, as shown in FIG. 1, a casing main body 1 and a casing cover 2 attached thereto form a pump chamber 3 in which a pair of rotors 4 and 4 are housed. The end surface 4a of each rotor 4 facing the casing cover 2 is different from the inner end surface 2a of the casing cover 2 by the rotor 4
Are substantially in contact with each other with a minimum gap required for rotation. And both rotors 4 are rotor drive shafts 5.
As a result, as shown by the arrow in FIG. 2, the pump tooth portions 6 of the rotors 4 engage with each other and synchronously rotate in opposite directions, whereby liquid is sucked into the pump chamber 3 from the suction port 7 and pressurized Then, it is discharged to the discharge port 8. In this case, the gap between the end surface 4a of the rotor 4 and the inner end surface 2a of the casing cover 2 facing the end surface 4a is almost in contact with the minimum minute gap necessary for the rotor 4 to rotate as described above. Therefore, the fluidity of the liquid in the minute gap is extremely poor. Therefore, even if the cleaning liquid is circulated in the pump chamber after the work of one day is completed, the cleaning liquid will not be discharged on the both end surfaces 4
There was a drawback that the cleaning effect could not be exerted due to insufficient distribution between a and 2a.

[0003]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the conventional apparatus and makes it possible to sufficiently flow the cleaning liquid into the gap between the rotor end face and the inner end face of the casing cover facing the rotor end face to enhance the cleaning effect. It is the main problem to be solved.

[0004]

In order to solve the above-mentioned problems, the invention according to claim 1 is such that a pump chamber 3 is formed by a casing body 1 and a casing cover 2 attached thereto, and the pump chamber 3 is formed. In a rotary pump that accommodates a pair of rotors 4 and 4 that rotate synchronously in opposite directions by engaging the pump tooth portions 6 of each rotor 4 with each other, a space 9 is provided in a part of the casing cover 2. In the space 9, a cover piston 10 that is movable in a far and far direction with respect to the rotor end surface 4a is installed, and an air cylinder 11 that reciprocates is attached to the casing cover 2,
The cover piston 10 has a structure in which it is connected to a piston rod 12 of an air cylinder 11.

According to the second aspect of the invention, a pump chamber 3 is formed by the casing body 1 and the casing cover 2 attached thereto, and the pump tooth portions 6 of the rotors 4 are engaged with each other in the pump chamber 3. In a rotary pump that accommodates a pair of rotors 4 and 4 that are synchronously rotated in opposite directions, a vacant space 9 is provided in a part of the casing cover 2, and the vacant space 9 is located near the rotor end surface 4a. A movable cover piston 10 is provided, an air cylinder 11 that reciprocates is attached to the casing cover 2, and a lock cylinder 14 having a lock bolt 13 is attached to the air cylinder 11. The piston 36 of the air cylinder 11 is connected to the piston rod 12a protruding from one end surface of the piston 36, and The piston rod 12b protruding from the end 36 or the other end face is in contact with the lock bolt 13, and the movement of the cover piston 10 is restricted by the lock bolt 13. .

In the invention according to claim 3 , a pump chamber 3 is formed by the casing body 1 and a casing cover 2 attached thereto, and the pump tooth portions 6 of the rotors 4 are engaged with each other in the pump chamber 3. In a rotary pump that accommodates a pair of rotors 4 and 4 that are synchronously rotated in opposite directions, a vacant space 9 is provided in a part of the casing cover 2, and the vacant space 9 is located near the rotor end surface 4a. The movable cover piston 10 is equipped and
As shown in FIG. 5, a plurality of reciprocating air cylinders 11 and 11A are attached to the casing cover 2 such that the piston rods 56 of the cylinder cylinders are connected to each other, and the cover piston 10 is connected to the piston rod 12. It is configured by adopting the following configuration.

In the invention according to claim 4 , a pump chamber 3 is formed by the casing body 1 and a casing cover 2 attached thereto, and the pump tooth portions 6 of the rotors 4 are engaged with each other in the pump chamber 3. In a rotary pump that accommodates a pair of rotors 4 and 4 that are synchronously rotated in opposite directions, a vacant space 9 is provided in a part of the casing cover 2, and the vacant space 9 is located near the rotor end surface 4a. The movable cover piston 10 is equipped and
As shown in Fig. 10, a plurality of reciprocating air cylinders 11 and 11A are attached to the casing cover 2 so that the piston rods 56 of the air cylinders 11 and 11A are connected to each other, and are locked to the rearmost air cylinder 11A. The bolt 13 is concentrically provided, the cover piston 10 is connected to the piston rod 12 of the frontmost air cylinder 11, and the piston 54 or the piston rod 54a of the rearmost air cylinder 11A is brought into contact with the lock bolt 13. The structure is such that the movement of the cover piston 10 is restricted by the lock bolt 13.

[0009]

1 and 2 show an embodiment of the present invention, in which a pump casing 15 accommodates a pair of rotors 4 on one end face side thereof and is integrally formed with a pump tooth portion. A casing body 1 in which a pump chamber 3 in which a loose fit rotation is formed is formed, and a suction port 7 and a discharge port 8 which communicate with the pump chamber 3 are formed, and a plane along the end faces of the pair of rotors 4. And a casing cover 2 that is detachably attached to the casing body 1 with bolts 16.

The casing cover 2 of each rotor 4
The through hole 19 is formed so as to face the side and communicate with the recess 17, and the spline inner peripheral surface 18 is formed. The distal end portions of the pair of hollow rotor drive shafts 5 are connected to the through hole. By forming the spline shaft 20 that engages with the spline inner peripheral surface 18 of 19 and fitting the spline shaft 20 into the through hole 19, the rotor 4 and the hollow rotor drive shaft 5 are accurately concentrically aligned. In a combined state, they are firmly coupled so as to rotate together.

The concave portion 1 formed in the rotor 4
The rotor tension fixing bolt 22 integrally formed with the collar portion 21 to be engaged with 7 is inserted from the recess 17 on the casing cover 2 side, and the rotor tension fixing bolt 22 is inserted through the hollow portion of the hollow rotor drive shaft 5. The rear end of the bolt 22 is exposed from the outer end surface of the hollow rotor drive shaft 5, and a tension fixing nut 23 is screwed into the exposed end to lock the nut 23 on the rear outer end surface of the hollow rotor drive shaft 5. With this, the rotor 4 is pulled toward the hollow rotor drive shaft 5 side, firmly abutted against the inner end surface of the distal end portion of the rotor 4 and fixed, and the lock nut 24 is screwed in appropriately. In addition,
With the collar portion 21 engaged with the concave portion 17, the collar portion 21
And the rotor 4 are formed flush with the casing cover 2.

The pair of hollow rotor drive shafts 5 are supported on bearings 26 and 27 by a gear box 25 adjacent to the pump casing 15, and in the gear box 25,
When the tuning drive gears 28 and 29 provided in the respective gears mesh with each other, they rotate in synchronism with each other.

Of the hollow rotor drive shafts 5, one hollow rotor drive shaft 5A is extended to the outside of the gearbox 25, and a cylindrical frame-shaped transmission is provided on the extended drive shaft portion. The coupling 30 is adapted to be connected.

When driving the rotary pump,
The rotational force of the transmission member 31 connected to the motor side is transmitted through the transmission member side coupling 32 to the transmission coupling 3
0, the coupling 30 rotates the hollow rotor drive shaft 5A on one side directly connected thereto, and the other hollow rotor drive shaft 5B via the pair of tuning drive gears 28 and 29. Rotation causes the pair of rotors 4 to rotate in synchronization with each other in opposite directions.

In the rotary pump shown in the above-mentioned embodiment, the side of the casing 4 facing the end face 4a of the casing 4 is recessed in the central portion of the casing cover 2 to form a space 9 having a constant width in the thickness direction of the casing cover 2. The cover piston 10 which is movable in the thickness direction, that is, in the perspective direction with respect to the rotor end surface 4a is airtightly fitted to this. Then, the air cylinder 11 is attached to the casing cover 2 concentrically with the cover piston 10 by the attachment bolt 33. The air cylinder 11 includes a cylindrical cylinder body 11a, a cylinder cover 34 on the casing cover 2 side, a cylinder cover 35 on the opposite side, a piston 36 that slides in the cylinder body 11a, and both sides of the piston 36. Projecting piston rod 12 (12a, 1
2b) and the air supply / exhaust holes 39, 4 communicating with the forward and backward movement side cylinder chambers 37, 38 on both sides of the piston 36, respectively.
0 is provided. The cylinder cover 34 on the casing cover 2 side may also serve as the casing cover 2 as illustrated. Further, it may be provided separately on the side of the air cylinder 11, and in this case, the void 9 of the casing cover 2 is provided so as to penetrate the casing cover 2. Alternatively, the cylinder cover 34 formed separately on the air cylinder 11 side may be used as the casing cover 2, and the shilling cover 34 and the casing cover 2 may be integrally formed. In this case, the cylinder cover 34 of the air cylinder 11 is directly attached to the casing body 1 as the casing cover 2 with bolts.

The end surface 10a of the cover piston 10 on the rotor 4 side is at a position flush with the inner end surface 2a of the casing cover 2 during normal work, and the end surface 4 of the rotor 4 is
It is in a substantially contact state with a through a minute gap. The piston rod 12a protruding from the piston 36 of the air cylinder 11 to the casing cover 2 side penetrates the cylinder cover 34 and is integrally connected to the cover piston 10, and the piston rod 12 protruding from the piston 36 to the opposite side.
b projects through the other cylinder cover 35 and projects to the outside. To be precise, the piston rod 12b has a collar 42 fitted to the small diameter portion 41 and a small diameter end bolt portion for fixing the collar 42. And a nut 43 that is screwed into the.

As shown in the drawing, a cylindrical lock cylinder 14 is also concentrically attached to the air cylinder 11 by a bolt 44, and the end wall 45 of the lock cylinder 14 has a piston of the air cylinder 11. A lock bolt 13 that can come into contact with the tip end surface of the rod 12b and that moves back and forth in the moving direction of the piston rod 12b is screwed together, and a lock nut 46 that locks the bolt 13 at a predetermined screwing position. Lock bolt 1
It is screwed to 3. The lock cylinder 14 is not limited to the cylindrical one as a matter of course.
The point is that the frame body can be moved forward and backward by screwing the lock bolt 13. Further, the piston rod 12b of the air cylinder 11 penetrates the cylinder cover 35 and projects outward, but without providing the piston rod 12b, the lock bolt 13 is moved from the cylinder cover 35 to the cylinder chamber 3.
7 may be airtightly fitted so that the tip of the lock bolt 13 is brought into contact with the piston 36.

3 differs from the embodiment shown in FIG. 1 in the shape of the cover piston 10A which is airtightly fitted in the space 9 provided in the casing cover 2, and in the embodiment shown in FIG. The rotor-side end surface 10a of the cover piston 10 is formed flush with the cover piston 1 shown in FIG.
In 0A, the head 47a of the bolt 47 is the rotor 4
Since it projects from the recess 48 for accommodating it
Are different in that they are formed. Incidentally, in this rotary pump, the rotor drive shaft 5 is provided at the center of the rotor 4.
And the rotor 4 is attached to the drive shaft 5 by screwing the above-mentioned bolt 47 into the screw hole 50 provided on the end face of the rotor drive shaft 5 with the fastening plate 49 interposed therebetween. .

Except for the shape of the cover piston 10A, the structure is the same as that of the above-mentioned embodiment, and therefore, the components having the same functions as those of the embodiment of FIG. Is omitted.

The present invention has the above-mentioned structure, and when operating as a normal rotary pump, as shown in FIG. 1 or 3, air is supplied from the air supply hole 39 of the air cylinder 11 to the forward side cylinder chamber 37. The piston 36 is moved forward to the left side in the drawing, whereby the cover pistons 10 and 10A are flush with the inner end surface 2a of the casing cover 2 and the end surface 4a of the rotor 4 is pressed.
And a state of being in contact with each other through a minute gap. When the piston 36 moves to the left side in the figure, the air in the left return-side cylinder chamber 38 is discharged to the outside from the exhaust port 40.

During the automatic operation by the air cylinder 11, the lock bolt 13 of the lock cylinder 14 is retracted from the tip end surface of the piston rod 12b on the right side of the air cylinder 11 in the figure, but when the rotary pump is operated. The internal pressure of the pump chamber 3 becomes a predetermined output or more and becomes higher than the pressing pressure of the piston 36 of the air cylinder 11,
The lock bolt 13 of the lock cylinder 14 can be kept in contact with the tip end surface of the piston rod 12b so that the cover pistons 10 and 10A do not retract from the end surface 4a of the rotor 4 and the pumping action does not decrease.

After the operation of the pump for one day is completed, the pump room 3
When cleaning the lock bolt, the knob 13 of the lock bolt 13
By operating a, the piston rod 12a is retracted from the tip end surface, air is press-fitted from the air supply hole 40 of the air cylinder 11 into the return-side cylinder chamber 38, and the air of the opposite cylinder chamber 37 is exhausted from the exhaust hole 39. By discharging and air in the space 9 between the casing cover 2 and the cover piston 10 is removed from the air vent 51 provided in the casing cover 2, as shown in FIG. 4 or FIG. By returning to the right side, the cover pistons 10 and 10A connected to the piston rod 12a retreat away from the end surface 4a of the rotor 4, and a large gap 52 is formed between the cover pistons 10 and 10A and the rotor end surface 4a. Since the cleaning water is formed in this state, by supplying the cleaning water into the pump chamber 3 through the suction port 7 shown in FIG. It can be discharged from the discharge hole 8 while flowing a large amount in the space 52 as indicated by an arrow, and the larger the amount of cleaning water sent and the faster its flow rate, the greater the cleaning effect can be. It is possible to effectively improve the cleaning action on the pump chamber 3, particularly the rotor end surface 4a and the inner end surface 2a of the casing cover 2 facing the rotor end surface 4a.

The rotor 4 may be rotated at a low speed or stopped, and it is preferable that the cleaning water is sent by a pump for cleaning water. In this case, the rotary pump does not need a bypass pipe for supplying the cleaning water. There is also an advantage.

In the case of manual operation, the air cylinder 11 is not used and the air supply / exhaust holes 39, 40 are kept free, only the lock cylinder 14 is used, and only the lock bolt 13 is attached to the piston rod 12b. The cover pistons 10 and 10A may be kept flush with the casing cover 2 by the contact pressure. At this time, in FIG. 1 or 3, the lock cylinder 14 is attached to the casing cover 2 via the air cylinder 11, but the air cylinder 11 is omitted and the lock cylinder 14 is directly fixed to the casing cover 2 with a bolt. However, the lock bolt 13 of the lock cylinder 14 may be brought into contact with the portion (rod portion 12a) of the cover piston 10 protruding from the casing cover 2.

Then, during the cleaning work, the lock bolt 1
3 is retracted from the tip end surface of the piston rod 12b, and the wash water is sent to the pump chamber 3 in this state, whereby the cover piston 10 is retracted from the rotor end surface 4a due to the water sending pressure, and a large gap 52 is formed between them. Occurs, and a large amount of washing water can be efficiently sent to the washing water to enhance the washing effect.

Further, as described above, the lock bolt 13 of the lock cylinder 14 is retracted from the tip end surface of the piston rod 12b on the right side of the air cylinder 11 in the figure, and when the air cylinder 11 is automatically operated, the rotary pump is used. The cover pistons 10 and 10A can have a role as a vented (relief) cover that can be adjusted so that the pump discharge pressure of the above does not rise above a certain level.

That is, air having a constant pressure is constantly supplied from the air supply hole 39 of the air cylinder 11, and the cover piston 1 is pressed by the piston 36 pressed by the air pressure.
0, 10A is held opposite to the pump action position of the rotor end surface 4a, and the pressure that the discharge pressure of the pump rises above a certain level to move the cover piston 10, 10A backward from the rotor end surface 4a is the pressing pressure of the piston 36. Larger than that, the cover piston 10 has a rotor end surface 4
As a result, the pump action is reduced and the discharge pressure is released, so that the pump discharge pressure of the rotary pump can be adjusted. Therefore, this discharge pressure can be freely set by the air pressure supplied into the air cylinder 11.

FIG. 6 shows another embodiment of the present invention. In the above embodiment, only one air cylinder 11 is provided, but in this embodiment, the air cylinder is 11, another air cylinder 11A is additionally installed with a bolt 53, the respective pistons 36 and 54 are connected by a piston rod 56 penetrating both common cylinder covers 55, and the lock bolt 13 is attached to the cylinder cover 57 of the latter air cylinder 11A. It is made by screwing. In the present embodiment, the two air cylinders 11 and 11A are connected to each other, but more air cylinders may be added, and in this embodiment, the lock bolt 13 is used. Is screwed into the rearmost air cylinder 11A, but as in the embodiment shown in FIGS. 1 and 3, a lock cylinder is attached to the rearmost air cylinder 11A, and a lock bolt is screwed into the lock cylinder. The lock bolt may be brought into contact with the piston or the piston rod in the same manner as the embodiment shown in FIGS. 1 and 3.

In this embodiment, the air is forced into the forward movement cylinder chamber 59 from the air supply hole 58 of the latter air cylinder 11A, so that the air passes through the through hole 60 provided in the piston rod 56. It is supplied to the forward movement cylinder chamber 37 of the other air cylinder 11, and the pistons 36 and 54 of both air cylinders 11 and 11A are simultaneously pressed, which is why the cover piston 1
The pistons 0, 10A are held by both pistons 36, 54 to strongly hold the rotor end face 4a at the pump action position on the rotor end face 4a. At this time, the cover bolts 10, 10A are fixed by the lock bolt 13 as required. As described above, it can be held in the working position.
Numerals 61 and 62 are air supply / exhaust holes provided in the return-side cylinder chambers 38 and 63 of both air cylinders 11 and 11A, and 63 is an air vent provided in the space 9.

[0030]

According to the invention of claim 1, a pump chamber is formed by the casing body and the casing cover attached to the casing body, and the pump tooth portions of the respective rotors engage with each other in the pump chamber. In a rotary pump that accommodates a pair of rotors that rotate in synchronism in opposite directions, a space is provided in a part of a casing cover, and the space is equipped with a cover piston that is movable in a perspective manner with respect to the rotor end face. Since an air cylinder is attached to the casing cover and the cover piston is connected to the piston rod of the air cylinder, when operating as a normal rotary pump, air is forced into the cylinder chamber from the air supply hole of the air cylinder. This causes the piston to move forward, which moves the cover piston inside the casing cover. It can be automatically brought to a position where it is flush with the end face of the rotor and in a substantially abutting state of the pump through a minute gap, and the pump operation for the day is completed. When cleaning the pump chamber, the piston moves back by pressurizing air from the air supply hole of the air cylinder into the returning side cylinder chamber, and the cover piston connected to the piston rod moves away from the end surface of the rotor. As described above, a large gap is formed between the cover piston and the end face of the rotor.In this state, by supplying the wash water from the suction port into the pump chamber, a large amount of wash water can be distributed in the large gap. It can be discharged from the discharge hole, which makes it possible to send a large amount of cleaning water to the pump chamber. The larger the amount of cleaning water sent and the faster the flow velocity, the greater the It will be able to raise the Do cleaning effect, the pump chamber, can be particularly effectively improve the cleaning action for the inner end surface of the casing cover facing the rotor end face and thereto.

Further, since the normal operation and the cleaning operation are switched by the air cylinder, remote automatic operation can be performed, and the operation can be performed promptly.

Further, according to the present invention, the cover piston can have a role as a vented (relief) cover that can be adjusted so that the pump discharge pressure of the rotary pump does not rise above a certain level.

That is, a constant pressure of air is constantly supplied from the air supply hole of the air cylinder, and the cover piston is held in opposition to the pump action position on the rotor end face by the piston pressed by the air pressure. When the pressure rises above a certain level and the pressure to retract the cover piston from the rotor end surface becomes larger than the pressing pressure of the piston, the cover piston retracts from the rotor end surface, reducing the pump action and releasing the discharge pressure. Therefore, the pump discharge pressure of the rotary pump can be adjusted. Therefore, this discharge pressure can be freely set by the air pressure supplied into the air cylinder.

According to the second aspect of the present invention, a pump chamber is formed by the casing body and the casing cover attached to the casing body, and the pump tooth portions of the rotors engage with each other in the pump chamber. In a rotary pump that accommodates a pair of rotors that rotate in synchronization with each other in a direction, a cavity is provided in a part of a casing cover, and the cavity is equipped with a cover piston that is movable in a perspective manner with respect to the rotor end surface. An air cylinder is attached to the casing cover, and a lock cylinder having a lock bolt is attached to the air cylinder, and the cover piston is connected to a piston rod protruding from one end surface of the piston of the air cylinder, and the piston Alternatively, the piston rod protruding on the other side is brought into contact with the lock bolt, Since the movement of the over the piston is adapted to be regulated by the lock bolt, supra to claim 1
It is possible to expect a pulling effect, and
The cover piston against the casing cover
By keeping the bar flush with the normal
It can be used for operating
In this case, move the lock bolt backward and wash in this state.
By sending purified water to the pump room,
The cover piston retracts from the rotor end face by
There is a large gap between workers, and a large amount of cleaning water is effective here.
Water can be efficiently supplied to enhance the cleaning effect.

According to the invention of claim 3 , a pump chamber is formed by the casing body and the casing cover attached to the casing body, and the pump tooth portions of the rotors engage with each other in the pump chamber. In a rotary pump that accommodates a pair of rotors that rotate in synchronization with each other in a direction, a cavity is provided in a part of a casing cover, and the cavity is equipped with a cover piston that is movable in a perspective manner with respect to the rotor end surface. A plurality of air cylinders are attached to the casing cover so that their piston rods are connected to each other, and the cover piston is connected to the piston rod. Therefore, the same effect as that of the invention according to claim 1 can be expected. In addition, it is possible to move the cover piston to the rotor end face with a plurality of air cylinders. Can let the strongly held in the position of operating conditions, it is possible to raise the discharge pressure of the much pump.

According to the invention of claim 4 , a pump chamber is formed by the casing main body and the casing cover attached to the casing main body, and the pump teeth of each rotor engage with each other in the pump chamber. In a rotary pump that accommodates a pair of rotors that rotate in synchronization with each other in a direction, a cavity is provided in a part of a casing cover, and the cavity is equipped with a cover piston that is movable in a perspective manner with respect to the rotor end surface. A plurality of air cylinders are attached to the casing cover so that their piston rods are connected to each other, and a lock bolt is concentrically provided on the rearmost air cylinder. It is connected to the piston rod, and the piston or piston rod of the rearmost air cylinder is In contact with the Kkuboruto, since the movement of the cover piston is adapted to be regulated by the lock bolt, effects listed to the invention of claim 2 as it is possible to expect, to the invention according to claim 3 As described above, the cover piston can be strongly held at the position of the pump operating state with respect to the rotor end surface by the plurality of air cylinders, and the discharge pressure of the pump can be increased accordingly.

[Brief description of drawings]

FIG. 1 is a partially longitudinal front view of a rotary pump showing an embodiment of the present invention.

FIG. 2 is a side view of the same.

FIG. 3 is a partially longitudinal front view of a rotary pump according to another embodiment.

FIG. 4 is a front view of relevant parts showing a usage state of the embodiment shown in FIG.

FIG. 5 is a front view of the main parts showing the usage state of the embodiment shown in FIG.

FIG. 6 is a front view of a main portion showing a usage state of the other embodiment.

[Explanation of symbols]

1 Casing body 2 casing cover 3 pump rooms 4 rotor 4a rotor end face 6 pump teeth 9 vacant places 10 Cover piston 11 Air cylinder 12 piston rod 13 Rock bolt 14 Lock cylinder

Claims (4)

(57) [Claims] 1. A pump chamber is formed by a casing main body and a casing cover attached to the casing main body, and a pair of rotors, which are engaged with each other by the pump teeth of the rotors and rotate in opposite directions, are formed in the pump chamber. In a housed rotary pump, a space is provided in a part of a casing cover, the cover piston is provided in the space and is movable to and from a rotor end face, and an air cylinder that reciprocally drives the casing cover is provided. A rotary pump that is attached and the cover piston is connected to the piston rod of the air cylinder. 2. A casing main body and a casing cover attached to the casing main body form a pump chamber, and a pair of rotors that rotate synchronously in opposite directions by engagement of pump tooth portions of each rotor with each other. In a housed rotary pump, a space is provided in a part of a casing cover, the cover piston is provided in the space and is movable to and from a rotor end face, and an air cylinder that reciprocally drives the casing cover is provided. A lock cylinder equipped with a lock bolt is attached to the air cylinder, and the cover piston is connected to a piston rod projecting on one end face of the air cylinder and a piston or a piston projecting on the other end face. The rod comes into contact with the lock bolt and the movement of the cover piston moves Rotary pump that is to be regulated by the door. 3. A casing main body and a casing cover attached to the casing main body form a pump chamber in which a pair of rotors which are engaged with each other by the pump teeth of the rotors and synchronously rotate in opposite directions. in housed rotary pump comprising, space is provided in a part of the casing cover, with perspective movable cover piston is equipped with respect to the rotor end face the voids, air to a plurality of reciprocating drive to the casing cover A rotary pump in which cylinders are mounted so that their piston rods are connected to each other, and a cover piston is connected to the piston rods. 4. A casing main body and a casing cover attached to the casing main body form a pump chamber, and a pair of rotors that rotate synchronously in opposite directions when pump teeth of each rotor engage with each other are formed in the pump chamber. in housed rotary pump comprising, space is provided in a part of the casing cover, with perspective movable cover piston is equipped with respect to the rotor end face the voids, air to a plurality of reciprocating drive to the casing cover The cylinders are attached so that their piston rods are connected to each other, and the lock bolt is concentrically provided on the rearmost air cylinder, and the cover piston is connected to the piston rod of the frontmost air cylinder. , The piston or piston rod of the rearmost air cylinder should not touch the lock bolt. , A rotary pump movement of the cover piston is adapted to be regulated by the lock bolt.