AY type hot oil Oil pump The series is a modification and redesign based on the old Y type centrifugal pump series. It is a new product developed to meet the needs of modern construction and quickly adapt to the upgrade of energy-saving focused equipment. It can be used in petroleum refining, petrochemical, chemical industry, and other media that do not contain solid particles such as petroleum, liquefied petroleum gas, and other flammable, explosive, or toxic liquids at high temperature and high pressure.

Description of the AY type stainless steel horizontal centrifugal pump model

　　Model description: 50AY60×2A

　　50—Pump inlet diameter of 50 mm

　　AY—Modified horizontal centrifugal pump

　　60—Single stage head at design point of 60 m

　　2—Number of pump stages: 2 stages

　　A—Impeller outer diameter cutting code

Structural features of the AY type stainless steel horizontal centrifugal pump

　　The AY type hot oil pump is divided into six structural forms: cantilever type with one stage and one suction, cantilever type with two stages and one suction, cantilever type with one stage and double suction, two-support type with one stage and double suction, two-support type with two stages and double suction, two-support type with two stages and one suction.

　　The AY type stainless steel pump casing is radially split, installed with support on the horizontal centerline, the inlet and discharge flange of the hot oil pump are oriented vertically upward, the shaft seal can use soft packing or interchangeable mechanical seal. The bearing housing is equipped with a set of radial ball bearings and a set of back-to-back axial ball bearings, lubricated with fine oil. For easy maintenance, it is not necessary to dismantle the suction or discharge pipes; an extended shaft coupling with elastic pins (can also be equipped with elastic diaphragm coupling) is used to easily disassemble the impeller, bearings, seals, and other parts.

　　1. All components of the bearing housing use advanced sliding bearings and axial thrust bearings, replacing the original bearing housings 35, 50, 60 with housings 45, 55, 70, improving reliability.

　　2. The hydraulic parts adopt an efficient and energy-saving hydraulic model, with an average efficiency 5-8% higher than the old Y type oil pump.

　　3. To maintain continuity, the structure, installation dimensions, and performance parameter range of the AY type pump remain the same as the Y type pump, facilitating the upgrade of old equipment.

　　4. High degree of parts standardization, standard parts are shared among various products in the series.

　　5. Refined material selection, mainly class II and III materials, with components such as the bearing housing made of cast steel and cast iron, providing favorable conditions for use in cold, exposed, and marine regions.

　　6. Bearings can be cooled by air, fan, or water, selected according to the pump's operating temperature. Fan cooling is especially suitable for areas with water scarcity or poor water quality.

Assembly and disassembly of the AY type stainless steel horizontal centrifugal pump

　　I. Disassembly

　　1. Disassembly sequence for cantilever type:

　　(1) When disassembling, first close the valve on the pipe, remove the pump cooling pipe, and disassemble the intermediate coupling and pump coupling.

　　(2) Unscrew the nuts of the bolts connecting the pump cover with the body and the support with the frame, and lift the rotor assembly, cover, and support horizontally out of the pump body.

　　(3) Unscrew the impeller nut, remove the impeller and key (for two-stage cantilever type, also remove the separator plate between stages).

　　(4) Unscrew the nuts of the bolts connecting the cover with the support and the seal pressure cover, remove the cover and then disassemble the seal parts in order.

　　(5) On the support, remove the front and rear bearing covers on both sides, separate the pump shaft from the support, and then remove the bearings inside the support.

　　2. Disassembly sequence for double-support type:

　　(1) When disassembling, first close the valve on the pipe, remove the pump cooling pipe, disassemble the intermediate coupling and pump coupling, and remove the key.

　　(2) Unscrew the nuts of the bearing cover and the dust cover screws.

　　(3) Loosen the nuts of the bolts connecting the bearing housing with the balance chamber cover, and remove the bearing housing from the pump shaft.

　　(4) Loosen the round bearing nut, remove in order the bushing, roller bearing, bearing cover, axial adjustment bushing, and dust cover.

　　(5) Use the same method to disassemble the bearing assembly at the other end.

　　(6) Unscrew the round nut of the seal and remove the seal.

　　(7) Unscrew the nuts connecting the pump body with the cover, and remove the cover horizontally.

　　(8) Remove the bushing, thrust bushing, and impeller of the second stage.

　　(9) Disassemble the bolts connecting the thrust plate and separator plate, and remove both plates.

　　(10) Remove the pump shaft and the first stage impeller horizontally, and disassemble the first stage impeller.

　　II. Assembly:

　　Perform the assembly in the reverse order of the mentioned disassembly.

　　III. Packing assembly and adjustment

　　1. Each packing chamber at both ends is designed with 5 packings, 2 arranged inside the packing ring and 3 outside the packing ring.

　　2. The cut of each packing must be aligned and flat, and the joints of two adjacent packings must be staggered by at least 90°.

　　3. The gland bolts must be tightened alternately and evenly, but without over-tightening the packing; the seal should allow a small leak, preferably in the form of drops.

Installation of AY type horizontal stainless steel oil centrifugal pump

　　I. Installation

　　1. The quality of the pump installation has an important impact on the stable operation and service life of the pump, so correction work must be done carefully and not hastily.

　　2. The height, length, and diameter of the pump suction pipe must meet the calculated values, trying to keep them short to reduce unnecessary losses (such as elbows), and ensuring that during operation the pump does not exceed its allowable margin against cavitation.

　　3. The suction and discharge pipes must have supports. The pump must not bear the load of the pipes.

　　4. The pump installation site must be spacious enough to facilitate maintenance.

　　5. Installation sequence:

　　(1) Place the assembly on the base with embedded anchor bolts, using pairs of shims between the base and the support for correction.

　　(2) Loosen the coupling, place a level on the pump shaft and on the base, and adjust the shims to level the assembly; properly tighten the anchor bolts to prevent movement.

　　(3) Pour concrete into the base and the holes of the anchor bolts.

　　(4) After the concrete has dried, check that the base and bolts have not moved. If all is well, tighten the anchor bolts and recheck the pump shaft level.

　　(5) Correct the concentricity between the pump shaft and the motor shaft; on the outer circle of the coupling, a deviation of 0.1 mm is allowed, and the gap between the surfaces of the two couplings should be 2 to 4 mm (use the smaller value for small pumps), with a uniform gap and a tolerance of 0.3 mm.

　　(6) After connecting the pipes and confirming the motor rotation direction, connect the coupling and verify the shaft concentricity again.

　　(7) After a real operation test of 2 to 3 hours, perform a final inspection; if there are no abnormalities, the installation is considered approved. During the test, check the temperature and vibration of the bearings as follows:

　　Standard temperature Allowed vibration intensity limit

　　Bearing

　　Type Sliding bearing

　　(Babbitt alloy) Roller bearing

　　Bearing speed n Maximum vibration intensity limit mm/s

　　Shaft centerline height

　　≤225mm >225mm

　　Temperature <60°C <65° 3000r/min 4.5 7.1

　　Schematic diagram of the extended coupling Maximum allowed deviation: X=0.2mm a=40

　　6. During installation, to prevent foreign objects from entering the machine, all holes of the assembly must be covered.

　　7. To prevent foreign objects in the pipes from entering the pump, a filter must be installed before the pump in the newly installed pipes, with an effective section 2 to 3 times larger than the suction pipe section.

Start and stop of AY type horizontal stainless steel oil centrifugal pump

　　1. Preparation for start-up

　　(1) Before starting, remove foreign objects from the machine and clean the area.

　　(2) Add the appropriate amount of lubricating oil.

　　(3) Before connecting the coupling, check the motor rotation direction to ensure it matches the pump rotation direction; after verification, connect the coupling.

　　(4) Before installing the coupling, manually move the pump shaft to ensure it rotates easily.

　　(5) Before starting, fill the pump with the liquid to be transported to expel air; at this time, the gate valve of the discharge pipe must be closed.

　　(6) When transporting hot oil, before starting, uniformly preheat the pump using hot oil continuously circulating through the pump body. The pump casing temperature must not be below 40°C at the inlet. The preheating rate is 50° per hour.

　　(7) Before starting, check that the base bolts are not loose and that the supply of lubricating oil, sealant, and cooling water is adequate.

　　2. Start-up

　　(1) Fully verify that all preparations are complete.

　　(2) Turn on the instrument switches and close the pressure gauge valve.

　　(3) Connect the power supply or start the turbine; when the pump reaches normal speed and the instruments indicate the corresponding pressure, gradually open the gate valve in the discharge pipe and adjust to the required working conditions. When the discharge pipe is closed, the pump's continuous running time must not exceed 3 minutes.

　　(4) During startup, pay constant attention to the motor power reading and the pump vibration; the vibration must not exceed 0.06 mm.

　　3. Maintenance:

　　(1) Regularly inspect the bearing heating; the temperature must not exceed the standard values indicated in the table, and constantly check the oil level, changing the lubricant periodically.

　　(2) Do not use the suction valve to regulate the flow to avoid cavitation.

　　(3) The pump must not operate continuously below 30% of the design flow; if it is necessary to operate under this condition, a bypass pipe must be installed at the outlet to return the excess flow to the pump inlet pipe.

　　(4) Pay frequent attention to leaks and seal heating.

　　(5) Frequently check for loosening of the anchor bolts, if the pump body temperature matches the inlet temperature, the fluctuations of the outlet pressure gauge, and the pump vibration.

　　(6) Pay attention to any strange noise during pump operation; if any anomaly is detected, promptly notify the corresponding personnel for handling.

　　4. Shutdown:

　　(1) Gradually close the gate valve of the discharge pipe.

　　(2) Cut off the power supply (or stop the steam turbine).

　　(3) After the pump has cooled down, close the cooling systems and the oil sealing pipes.

　　(4) Drain and clean the liquid inside the pump and the cooling water to prevent freezing and adhesion.