JP3061550U - Vacuum pump for fire pump priming - Google Patents

Abstract

(57) [Summary] [Problem] A vacuum pump for priming a firefighting pump capable of achieving a desired purpose even in a low-speed rotation range without damaging a blade even if liquid is contained in intake air. I will provide a. SOLUTION: A casing 10, covers 13 and 14 for closing both ends thereof, and a rotor 15 rotating at an eccentric position in the casing 10 are formed in the same manner as in the related art, and a support provided by cutting into both ends on the diameter of the rotor 10. Blades 19a to 19d sliding in and out of the grooves 18a to 18d are formed of a polyether-ether-ketone resin containing a lubricant and carbon fiber so as to communicate with a support groove located on the diameter of the rotor 10. One of the blades is pushed into the support groove on the inner periphery of the casing 10 in a state where the interval between the two blades in the both support grooves is the shortest distance in the communication hole 22 provided through the rotating shaft 16. The other blade is inserted through a pin 23 that is pushed out of the support groove so as to slide on the inner periphery of the casing 10, and is seen through the casing 10 in the rotation direction of the rotor 15. Outlet 25 before the exhaust port 12
Is provided.

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 This invention relates to a vacuum pump for generating a priming vacuum in a fire pump prior to operation of the fire pump.

[0002]

[Prior art]

 If the above-mentioned vacuum pump is lubricated, lubricating oil is discharged on the road during operation and pollutes the environment. Therefore, as a non-lubricating vacuum pump that does not pollute the environment, a casing made of bronze casting having an intake port and an exhaust port on a cylindrical peripheral surface, and a cover made of bronze casting that closes both left and right ends of this casing. A rotating shaft that is supported eccentrically through the casing with both ends supported by the cover, a bronze cast rotor that is fixed at the center of the rotating shaft and rotates integrally, and a radial cut into the rotor. Each of the plurality of support grooves provided is slidably inserted into the support groove one by one in the in-out direction, and the outer end slides on the inner periphery of the casing with the rotation of the rotor to slide in the in-out direction in the support groove. It is known to use a plurality of blades formed of resin-containing carbon.

[0003]

[Problems to be solved by the invention]

The oilless vacuum pump described above can operate without oil because the carbon containing the resin that forms the blade has self-lubricating properties, but can operate without oil. However, since the bending strength of the blade is as low as about 600 kgf / cm ^2, However, if liquid is mixed into the air sucked into the intake port, liquid compression will occur in the compression process before the exhaust port when viewed in the direction of rotation of the rotor, and the liquid compression will damage the blade. . Therefore, it is necessary to arrange a gas-liquid separator in front of the suction port of the vacuum pump to remove the liquid component in the air sucked into the suction port. In addition to being bulky, the installation space for the gas-liquid separation device must be created in the narrow space of the fire engine, and the gas-liquid separation device must be supported by a support structure, which requires considerable effort.

[0004]

[Means for Solving the Problems]

 The vacuum pump for priming the fire pump of the present invention is made to solve the above-mentioned problems, and includes a casing, a cover for closing both ends thereof, and a rotor rotating at an eccentric position in the casing as in the past. The blades are made of bronze castings, but the blades that slide in and out of a plurality of pairs of support grooves that are cut radially at both ends on the diameter of the rotor are made of polyether containing lubricant and carbon fiber.・ Molded with ether / ketone resin (PEEK), and two communication holes formed through the rotating shaft so as to communicate with two support grooves located on the rotor diameter. With the spacing between the blades being the shortest distance, one of the blades is pushed into the support groove on the inner periphery of the casing so that the other blade slides against the inner periphery of the casing. Extruding pin inserted through, is provided with a relief port of the liquid also serves as a heat radiation in front of the exhaust port as viewed in the direction of rotation of the rotor in the casing compressed.

[0005]

[Embodiment of the invention]

 In the embodiment shown in FIGS. 1 and 2, reference numeral 10 denotes a casing having an intake port 11 and an exhaust port 12 on a cylindrical peripheral surface, and 13 and 14 contact bolts at right and left ends of the casing 10 to secure bolts. , A cover that closes each end of the casing 10, and 15 denotes a rotor that rotates around a rotation center eccentric from the center line of the casing 10, and these casing 10, the covers 13, 14, and the rotor 15 are made of a bronze casting. It is made.

The covers 13 and 14 have a bearing at the position of the center of rotation of the rotor 15 eccentric from the center line of the casing 10, and the rotating shaft 16 made of stainless steel is rotatably supported in the casing 10 by the bearing. The rotor 15 has its center hole fitted on the rotating shaft 16 and is coupled by a key so as to rotate integrally with the rotating shaft 16. Further, a gear 17 that receives rotational power is fixed to an end of a rotating shaft 16 that protrudes outside from one cover 13.

The rotor 15 is provided with a plurality of support grooves 18 radially cut from the outer periphery at equal intervals in a circumferential direction, and a blade 19 can be slid one by one in each support groove 18 in and out of the support groove 18. Has been charged. When the rotor 15 is rotated in the direction of the arrow in FIG. 2 by the rotation shaft 16, the outer end 20 of each blade 19 comes into sliding contact with the inner periphery of the casing 10, and the center of rotation of the rotor 15 moves from the center line of the casing 10. Due to the eccentricity, the blade 19 slides in and out of the support groove 18.

In the embodiment shown in FIGS. 1 and 2, four supporting grooves 18 a, 18 b, 18 c, and 18 d are provided in the rotor 15 with a phase of 90 degrees in the radial direction, and the blades 19 a, 19 b, 19 c, and 19 d are provided. , The blade 19a and the blade 19c face each other on the diameter of the rotor 15, and the blade 19b and the blade 19d also face each other on the diameter. Therefore, when the rotor 15 rotates and the blades 19a, 19d (19c, 19b) slide outward in the support grooves 18a, 18d (18c, 18b), the blades 19c, 19b (19a, 19b). 19d) slides in a direction into the support grooves 18c, 18b (18a, 18d).

In order to reliably slide the blades 19a, 19b, 19c, and 19d in the opposite directions, a series of communication holes 22 are formed in the bottoms of the support grooves 18a and 18c and the rotating shaft 16 so that the pins 23 Is slidably inserted, a series of communication holes 22 are opened at the bottom of the support grooves 18b and 18d and at another position of the rotating shaft 16, and the pin 23 is slidably inserted.

Here, the length of the pin 23 will be described. The length of the pin 23 is determined in a state where the interval between the two blades 19 is the shortest, that is, in the position of the blades 19a and 19c shown in FIG. The length of both ends substantially abuts on the inner end 21 of 19c. At the positions of the blades 19b and 19d shown in FIG. 2, since the blades 19b and 19d are located on a straight line passing through the center of the casing 10 and the rotor 15, the distance between the blade 19b and the blade 19d is longer than the longest distance. As a result, the length becomes longer than the length of the pin 23, and a gap is generated between the pin 23 and the blade 19b and / or the blade 19d.

Therefore, in the case of the blades 19a and 19c shown in FIG. 2, even in a low-speed rotation region where the blade 19a is hard to protrude from the support groove 18a due to centrifugal force, the blade 19c whose outer end 20 is pressed on the inner periphery of the casing 10 is formed. Pushes the inner end 21 of the blade 19a through the pin 23 to give the initial movement, so that the blade 19a reliably projects from the support groove 18a by the pressing force and the centrifugal force of the blade 19c through the pin 23, and the outer end The intended purpose can be achieved because the part 20 is securely brought into sliding contact with the inner periphery of the casing 10.

As shown in FIG. 3, the intake port 11 and the exhaust port 12 are provided at a phase of about 230 degrees with respect to the center O of the casing 10. The eccentric gap 24 between the outer periphery of the rotor 15 and the inner periphery of the casing 10 is located approximately 120 degrees from the intake port 11 in front of the intake port 11 when viewed in the rotation direction of the rotor 15. The cross-sectional area gradually increases in the front half 24a to the position, and the cross-sectional area rapidly decreases in the rear half 24b from that position to the exhaust port 12.

The suction port 11 of this vacuum pump is connected to the top of the housing of the fire pump by piping, and the eccentric gap 24 is separated from the suction port 11 by the rotation of the rotor 15 by two blades 19 before and after passing through the suction port 11. (The air at the top of the fire pump housing) is inflated until the rear blade 19 passes through the front half 24a of the eccentric gap 24, and the rear blade 19 is When passing through the first half 24a of the eccentric gap 24 after passing through the first half 24a of the eccentric gap 24, the air between the front and rear blades 19 is rapidly compressed and generates heat, and the heat causes the casing 10, the covers 13, 14, the rotor 15, When the rotary shaft 16 and the blade 19 are heated and a liquid is contained in the air, the liquid is compressed.

When the front blade 19 passes through the exhaust port 12, the compressed heated air and liquid components are mainly discharged from the exhaust port 12. When the blade 19 is formed of carbon containing a self-lubricating resin, the bending strength is as low as about 600 kgf / cm ² , as described above. In this case, the pressure of the liquid compression generated in the compression process cannot be tolerated, and the blade 19 is damaged.

[0015] Therefore, after examining various molding materials for the blade 19 and repeating tests, a polyether ether ketone resin (PEEK) containing a lubricant and carbon fiber (trade name of Green Tweed and Company Japan Co., Ltd.) 1555) to form the blade 19. The reason is that PEEK has a bending strength of 2150 kgf / cm ² , withstands the pressure generated by liquid compression and does not break.

The bronze casting (BC6) for forming the casing 10, the covers 13, 14 and the rotor 15 has a coefficient of thermal expansion of 3.1 × 10 ⁻⁵ cm / cm / ° C. and a coefficient of thermal expansion of 16 × 10 ^-6 cm / cm / ° C., the casing 10 is provided with an escape port 25 for liquid compression which also serves as a heat radiator in front of the exhaust port 12 when viewed in the rotation direction of the rotor 15 in the casing 10 and is heated in the compression process. By discharging the air from the outlet 25, the rise in the temperature of the casing 10, the covers 13, 14, the rotor 15, the rotating shaft 16, and the blade 19 is suppressed, the expansion of the blade 19 due to the thermal expansion is suppressed, and the liquid is compressed. Thus, the applied pressure is reduced.

In the case of a vacuum pump having a total displacement of about 960 cc per revolution, the diameter of the relief port 25 is most effective at 9 mm. However, the diameter of the exhaust port 25 per revolution of the vacuum pump is most effective. Based on this, it is necessary to experiment to find the optimal dimensions.

As shown in FIGS. 3 and 4, in the case of a vacuum pump having a total displacement of 960 cc per rotation, the inner diameter D1 of the casing 10 is set to about 126 mm, and the axial length L1 (the left and right covers) is set. 13 and 14) to about 169 mm, the diameter D2 of the rotor 15 to about 110 mm, the axial length L2 to about 169 mm, and the eccentric distance E of the center of the rotor 15 with respect to the center of the casing 10. Four support grooves 18 having a thickness T1 of about 7 mm and a depth d of about 35 mm are formed in the radial direction.

Considering that the coefficient of thermal expansion of PEEK is considerably larger than that of bronze, the blade 19 has a thickness T2 of less than 7 mm, a radial length of less than 35 mm, a width of less than 169 mm, and a blade 169 mm. The distance (ΔL) between the inner surface between the left side surface of the blade 19 and the left cover 13 and the distance (ΔR) between the inner surface between the right surface of the blade 19 and the right cover 14 were set to about 0.11 mm in total.

The casing 10, the covers 13, 14, the rotor 15, and the blade 19 having the above dimensions are assembled so that the diameter of the escape port 25 of the casing 10 is 9 mm, and the total exhaust amount per rotation is 960 cc. A vacuum pump was manufactured, and one of the pumps was used as an example of the present invention, and the other was used as a comparative example in which the escape port 25 was closed with a plug, and an in-house test was performed under the same conditions.

First, in the vacuum performance test (test for clearing 84% of atmospheric pressure within 30 seconds), the atmospheric pressure is 706 mmHg (84% of which is 593 mmHg), and the rotation speed of the rotor 15 is 1360 rpm. p. m. Met. In the comparative example, the atmospheric pressure of 84% was reached in 20 seconds, and the degree of vacuum after 30 seconds was 620 mmHg. In contrast, in the embodiment of the present invention, the atmospheric pressure of 84% was reached in 23 seconds in 30 seconds. After 2 seconds, the degree of vacuum was 607 mmHg. That is, the comparative example in which the escape port 25 was closed cleared the atmospheric pressure by 84% 3 seconds earlier, and the vacuum degree after 30 seconds was 13 mmHg higher in the comparative example. However, the embodiment of the present invention also passed the vacuum performance test sufficiently because 84% of the atmospheric pressure was cleared in 23 seconds.

Next, Table 1 and FIG. 5 show the results of a 30-minute durability test in which the intake port 11 was fully closed. The test conditions were such that the rotation speed of the rotor 15 was 1350 r. p. m. The atmospheric pressure was 705 mmHg, and the surface temperature of the casing 10 was measured at the measurement position shown in FIG.

[0023]

[Table 1]

As is clear from Table 1, the vacuum pump of the comparative example in which the escape port 25 is closed quickly reaches the degree of vacuum, but the surface temperature rises to 292 ° C. 12 minutes after the start of operation, and Due to the heat, the blade 19 extends in the left-right direction beyond the gap provided about 0.11 mm in total between the left and right side surfaces of the blade 19 and the inner surfaces of the left and right covers 13 and 14 and rubs with the covers 13 and 14 to rotate. The number gradually decreased, and seizure stopped 14 minutes after the start of operation.

On the other hand, in the vacuum pump according to the embodiment of the present invention in which the escape port 25 is opened, although the degree of reaching the degree of vacuum is slower than that of the comparative example, the surface temperature is at most 277 ° C. for 22 minutes after the start of operation. After that, the number of rotations of the rotor 15 decreased the most at 1342 r. p. m. Then it gradually rose. The ultimate vacuum gradually increased from 565 mmHg after 2 minutes to 647 mmHg after 30 minutes. The operation of the vacuum pump according to the embodiment of the present invention was stopped in 30 minutes, but it was still possible to continuously operate the vacuum pump sufficiently.

After the model acquisition test by the Japan Fire Service Certification Association before 1997, that is, the durability test for 30 minutes with the intake port 11 fully closed, and the durability test for 30 minutes described above, 84% of the atmospheric pressure Must be reached within 30 seconds or must pass a vacuum performance test. As described above, in the vacuum pump of the comparative example in which the escape port 25 is closed, the right and left side surfaces of the blade 19 and the left and right covers 13 and 14 are stopped by seizure within 14 minutes after the start of operation. The model cannot pass the durability test of the model acquisition test. On the other hand, since the vacuum pump of the embodiment of the present invention can continue to operate for more than 30 minutes, it passed the durability test of the type acquisition test sufficiently. % (593 mmHg), and the ultimate vacuum after 30 seconds is 601 mmHg, so that this vacuum performance test is sufficiently passed.

[0027]

[Effect of the invention]

 As described above, according to the present invention, a plurality of blades sliding in and out of the support groove in the support groove while the outer end slides on the inner periphery of the casing with the rotation of the rotor are made of lubricating resin. Molded from polyether ether ketone resin (PEEK) containing lubricant and carbon fiber, which has much higher flexural strength than the carbon contained, the liquid mixes into the air sucked in through the air inlet and the pump Even if liquid compression occurs in the compression step, the blade will not be damaged by the pressure. Since the thermal expansion coefficient of PEEK is much larger than that of bronze, the casing is provided with an outlet for liquid compression, which also serves as a heat radiator, in front of the exhaust port when viewed in the direction of rotation of the rotor. Exhausted air is discharged from this outlet to suppress the rise in the temperature of the casing, cover, rotor, rotating shaft and blades, to suppress the expansion due to the thermal expansion of the blades, and to reduce the pressure applied by liquid compression. I can sum up.

Further, a plurality of communication holes provided through the rotary shaft so as to communicate with the two support grooves located on the diameter of the rotor are inserted, and one blade is inserted into the support groove at the inner periphery of the casing. It has a plurality of pins that push the other blade out of the support groove so that the other blade slides against the inner periphery of the casing by being pushed into the casing. One blade, whose outer end is pushed on the inner periphery of the casing, pushes out the inner end of the other blade via a pin to give initial movement, so that the other blade pushes the pressing force of one blade via the pin and The intended purpose can be achieved because the outer end portion reliably projects from the support groove by the centrifugal force and the outer end portion reliably slides on the inner periphery of the casing.

[Brief description of the drawings]

FIG. 1 is a front view of a cross section of a part of a vacuum pump according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view corresponding to line II-II in FIG.

FIG. 3 is a schematic explanatory diagram of FIG. 2;

FIG. 4 is a schematic explanatory diagram of FIG. 1;

FIG. 5 is a graph showing the results of a durability test in which the suction port of the vacuum pump according to the embodiment of the present invention and the conventional pump are fully closed.

[Explanation of symbols]

REFERENCE SIGNS LIST 10 casing 11 intake port of casing 10 12 exhaust port of casing 10 13 cover 14 cover 15 rotor 16 rotating shaft 17 gear 18 support groove of rotor 15 19 blade 20 outer end 21 of blade 19 21 inner end of blade 19 communication hole 23 Pin sliding in communication hole 22 24 Eccentric gap between outer periphery of rotor 15 and casing 10 24a First half of eccentric gap 24b Second half of eccentric gap 24 25 Escape port

Claims (1)

[Utility model registration claims] 1. A casing made of a bronze casting having an intake port and an exhaust port on a cylindrical peripheral surface, a cover made of a bronze casting for closing left and right ends of the casing, and both ends supported by the cover. A rotating shaft penetrating eccentrically through the casing, a rotor made of a bronze casting fixed at the center of the rotating shaft and integrally rotating, and a plurality of pairs of radially cut ends provided at both ends on the diameter of the rotor. Are inserted one by one into the supporting groove so as to be slidable in the entering and exiting direction, and with the rotation of the rotor, the outer end slides on the inner periphery of the casing to slide in the entering and exiting direction in the supporting groove. A plurality of blades made of a polyether ether ketone resin containing a lubricant and carbon fibers, and a plurality of blades provided so as to penetrate the rotating shaft so as to communicate with the two support grooves located on the diameter of the rotor. In the state where the distance between the two blades in the two support grooves is the shortest distance, the one blade is pushed into the support groove at the inner periphery of the casing, and the other blade is inserted into the communication hole. A plurality of pins for extruding from the support groove so as to be in sliding contact with the inner periphery of the casing, and a relief port for liquid compression which also serves as heat radiation is provided in front of the exhaust port in the casing when viewed in the rotation direction of the rotor. A vacuum pump for priming a fire pump.