DYD, DYDG, DYDF Pump Samples.docx  

  1. Overview

  DYD The DYD type pump is a single-suction, multi-stage segmented centrifugal clean water pump, suitable for conveying clean water without solid particles or liquids with physical and chemical properties similar to clean water. The temperature of the conveyed medium is -20 ℃ ~80 ℃.

  DYDF 、 DYDG The DYDG type pump is a single-suction, multi-stage segmented corrosion-resistant centrifugal pump, suitable for conveying corrosive liquids without solid particles. The temperature of the conveyed medium is -20 ℃ ~80 ℃.

2. Model Description

Example: DYD, DYDG, DYDF 85-45X8

DYD, DYDG, DYDF — Multi-stage, segmented centrifugal water pump

85 — Pump flow rate (m3/h)

45 — Single-stage head is 45m

8 — Number of pump stages is 8

3. Structural Description

 1 Pump Casing Section

  The pump casing section mainly consists of the bearing housing, front section, middle section, rear section, and guide vanes, all bolted together as a whole. The front suction inlet and rear discharge outlet have two different directional combinations: horizontal or vertical (depending on the specific pump model).

 2 Rotor Section

  The rotor section mainly consists of the shaft and parts mounted on the shaft such as impellers, shaft sleeves, and balance discs. The parts on the shaft are fixed with keys and shaft sleeve nuts to form an integral unit with the shaft. The entire rotor is supported by bearings at both ends on the pump casing. The number of impellers in the rotor section depends on the number of pump stages.

 3 Bearing Section

  This type of pump uses sliding bearings and rolling bearings depending on the model (among them, 85-67 and 155-67 use sliding bearings, while the others use rolling bearings). None of these bearings bear axial force. During operation, the rotor components are allowed to axially float within the pump casing; centripetal ball bearings cannot be used.

 4 Pump Sealing

  The sealing surfaces between the front, middle, and rear sections of the pump use molybdenum disulfide grease seals. The sealing between the rotor and fixed parts relies on sealing rings and guide vane sleeves. When the wear of the sealing rings and guide vane sleeves affects the pump's operation and performance, they should be replaced promptly.

  The shaft seal can be either packing or mechanical seal type. The sealing chamber must be supplied with water at a certain pressure to serve as a water seal, water cooling, or water lubrication. Replaceable shaft sleeves are installed at the shaft seal to protect the pump shaft.

 5 Balancing Mechanism

  The balancing mechanism consists of balance plates, balance sleeves, and balance discs. It is used to balance the axial force of the pump.

4. Rotation Direction

  The rotation direction of this pump, viewed from the motor end towards the pump, is clockwise.

(File Download DYD, DYDG, DYDF Pump Samples.docx )

6. Arrival Inspection

Upon arrival, the equipment should be inspected immediately. Any defects caused by transportation should be reported to the carrier immediately. The instruction manual and other component manuals (such as the motor) and packing lists should be kept in a safe and convenient place for reference at any time.

7. Pump Assembly and Disassembly

1. Pump Assembly This DYD, DYDG, DYDF The assembly quality of the pump directly affects whether the pump can operate normally, as well as the pump's service life and performance parameters; it also affects the vibration and noise of the unit. The following points should be noted during assembly:
   1. The concentricity of the fixed parts after assembly depends on the manufacturing accuracy and assembly quality of the parts. The machining accuracy and surface roughness of the parts must be ensured, and no bumps or scratches are allowed. The molybdenum disulfide used as a sealant must be clean. Screws and bolts used for fastening should be evenly stressed.
   2. The alignment of the impeller outlet flow channel and the guide vane inlet flow channel depends on the axial dimensions of the parts. The quality of this alignment directly affects the pump's performance, so the pump dimensions must not be adjusted arbitrarily.
   3. After the pump assembly is completed and before packing is installed, manually rotate the pump rotor to check whether the rotor rotates flexibly within the casing and whether the axial clearance meets the specified requirements.
   4. After the above checks meet the requirements, add packing at the shaft seals at both ends of the pump, paying attention to the relative position of the packing rings in the packing chamber.
2. Pump Disassembly
   1. Disassembly should be performed in the reverse order of assembly. During disassembly, the manufacturing accuracy of parts must be strictly protected from damage.
   2. When disassembling the tie rods, the middle sections should be supported with shims first to prevent the middle section joints from loosening and sinking, which could bend the shaft.

8. Pump Installation

This DYD, DYDG, DYDF When installing the model pump, in addition to meeting general installation technical requirements, the following points should also be noted:

1. When the motor and pump are installed together, the pump coupling end should be axially pulled out and leave 2-3mm a face clearance value to ensure the axial clearance between the two couplings of the pump and motor.

Note: Ensure the base plate is leveled and the equipment is properly horizontal before grouting.

Caution: To ensure successful installation, the coupling adjustment must be correct. Flexible couplings cannot compensate for any obvious misalignment. Misalignment may cause rapid wear, noise, vibration, and damage to the equipment. Therefore, the coupling must be adjusted within the specified limits.

Caution:

1. Measures must be taken to support the pump's inlet and outlet pipelines to prevent excessive load on the pump's inlet and outlet. 2. The centerlines of the pump and motor shafts should be on the same horizontal line.

3. The pump can only bear its own internal forces and cannot bear any external forces.

9. Pump Start-up, Operation, and Shutdown

( 1. ) Start-up:

Warning: For the safety of the operator, do not operate beyond the conditions specified on the pump nameplate to avoid endangering the safety of the equipment and personnel. To ensure smooth operation and maintenance of the pump and other actions, please refer to the manual.

1. Before starting the pump, manually rotate the rotor to check if it moves freely.
2. Check whether the motor rotation direction matches the pump's rotation direction.
3. Close the pump outlet gate valve and pressure gauge cock, and use the conveyed liquid or vacuum system to remove air from the suction pipe and pump body (starting the pump dry is strictly prohibited).
4. Check the tightness of the bolts connecting the pump and motor and the safety around the pump to ensure the pump is ready to start.

Warning: The equipment can only be operated after the coupling guard is installed; ignoring this may cause injury or death.

1. Start the pump. After the pump runs normally, open the pressure gauge cock, slowly open the outlet gate valve, and control the pump's designated head according to the outlet pressure gauge reading.

(2) Operation:

1. This DYD, DYDG, DYDF The model pump balances axial force through an internal balance mechanism. The balance device discharges balance liquid, which is connected by a balance water pipe to the suction section or a short pipe is set at the balance chamber. The balance liquid flows out of the pump through the short pipe. To ensure normal pump operation, the balance water pipe must never be blocked. 。
2. This DYD, DYDG, DYDF The model pump's rolling bearings have no cooling device. Bearing temperature rise reflects the pump's assembly quality. The bearing temperature rise must not exceed the ambient temperature. 35 ℃, and the maximum temperature should not exceed 75 ℃.

Warning: Operating equipment without proper lubrication may cause bearing overheating, breakage, pump seizure, equipment damage, and personal injury to operators.

1. The rotors of DYD, DYDG, and DYDF model pumps have certain axial movement during operation. The axial clearance between the motor and pump coupling faces must be ensured.
2. During pump operation, regularly check the wear of the impeller, sealing ring, guide vane sleeve, balance disk, and shaft sleeve. Replace them promptly if wear is excessive.

Warning: Do not attempt maintenance, servicing, or cleaning near rotating machinery, as it may endanger the operator's personal safety.

1. Users should formulate detailed operating procedures based on specific conditions.

(3) Shutdown:

Before shutdown, first close the pressure gauge cock, then slowly close the outlet gate valve. Only after the outlet gate valve is fully closed can the motor be stopped.

10. Possible Pump Faults and Solutions