Vacuum self-priming pump for the negative pressure to start the pump, start with the vacuum pump before the pump and suction pipe air out and filled with water to start the pump, the pump starts to close the valve start. In addition to ensure that the vacuum self-priming pump centrifugal pump water intake pump can be normal, set two vacuum pump exhaust volume (Q = 2m3 / -10m3 / min range according to the actual length of the pipeline length, my company technicians can choose for you, V Degree of vacuum) = 0 ~ 200hpa). Vacuum self-priming pump group to take the pump and its piping system control can be centralized control of the pump station operator station can also be operated locally. Take the pump to achieve automatic interlock between the pump (that is, a pump failure, the standby pump automatically put into operation). Vacuum pump, water pump to achieve automatic program-controlled start of the pump; normal stop pump, the pump outlet by the electric butterfly valve to complete the full off after the chain can automatically stop the pump. 1) The horizontal arrangement of the pump, pump and motor installed on the same basis. Vacuum self-priming pump group pumps 2) Bo Yu pump performance curve provided in the design conditions within the flow, lift, efficiency is not allowed to have negative deviation, and the positive deviation of the head should not exceed 5%, lift Flow curve from the design flow to zero flow should gradually rise between the pump structure design should take into account the motor speed can be 20% of the conditions. Pump rated operating conditions, the efficiency should be in the best efficiency range. As the vacuum self-priming pump water flow caused by pump reversal, the reverse speed reaches 120% of rated speed, the pump and motor from damage. The pump (motor) can be started when the pump reverses no more than 20% of the rated speed. 3) Vacuum self-priming pump pump Q ~ H curve must be smooth from the design point up to close the head point. Shut-off head should be greater than the design point head, pump curve in any case to meet the system resistance requirements. 4) Vacuum self-priming pump The horizontal, vertical and torque generated by the pump under various conditions (including when the pump is closed and reversed) should also include the force and moment due to the earthquake and temperature changes By the pump unit to withstand the body, passed to the base of the pump base. 5) vacuum self-priming pump group pump bearings and seals without the need for pre-lubrication start, no external water supply lubrication structure and allows the transient dry start. The required lubrication water after the pump is started will be extracted by the pump outlet pipe and filtered to lubricate / cool the pump bearing and shaft seal assembly. Pump seal body using mechanical seal. 6) vacuum self-priming pump group pump normal operation, require the pump has good cavitation performance, and to ensure that does not produce cavitation, vibration phenomenon. 7) vacuum self-priming pump group pump material: pump body made of cast iron, pump bearings using high-quality imported SKF, impeller wear-resistant 304 stainless steel, the rest by the seller according to conventional materials selection. 8) vacuum self-priming pump pump housing to be equipped with automatic exhaust valve. 9) Vacuum self-priming pump The pump is connected with the motor by a rigid coupling. The coupling should be provided with a detachable and solid protective cover. 10) vacuum self-priming pump pump still need to work in the high-efficiency area when NPSH = 5m. Vacuum self-priming pump group motor basic requirements (1) the motor is a three-phase asynchronous motor. (2) Tolerance of basic performance guaranteed value of motor: 1) Efficiency: -0.1 (1-h) Indirect method 2) Power factor (cosf) :-( 1-cosf) / 6 3) Maximum starting current: guaranteed value 20% 4) Maximum starting torque: -15% of guaranteed value 5) Maximum torque; -10% of guaranteed value (3) When the frequency is rated and the deviation of the power supply voltage from the rated value does not exceed ± 5% The motor should output the rated power. (4) When the voltage is rated, and the deviation of the power supply frequency from the rated value does not exceed ± 1%, the motor shall output the rated power. (5) The vacuum self-priming pump group motor rated power shall not be less than the capacity of the motor-driven equipment required for long-term continuous operation, the value should be greater than the maximum braking power. In the full voltage direct start, the motor rated power overload value to meet GB755 standards. (6) vacuum self-priming pump motor rated voltage 380V. Rated frequency is 50Hz. (7) vacuum self-priming pump group motor must be able to start at 85 ~ 100% of the rated voltage and rated power, and accelerate the start of the device. (8) The motor shall be capable of withstanding all thermal and mechanical stresses at the design ambient temperature and shall be capable of achieving satisfactory operating characteristics when the terminal voltage is maintained at 100% of its rated value. (9) Stall current of three-phase asynchronous induction motor, which can not exceed 750% of the full load current without consent of the demand side. (10) Motor room layout, protection class IP54. Cooling using self-cooling. (11) The motor housing shall be properly grounded. (12) The lead grounding device should be installed in the main motor terminal box. (13) The motor should have class F insulation rating (temperature rise according to class B assessment), the junction box protection class is at least IP55. (14) The bearing structure of the motor should be sealed to prevent dirt and water, and can not make the lubricant into the coil. (15) motor housing and motor base should be anti-rust measures. (16) The critical speed of the shaft should be at least 25% greater than the rated speed. 3.2.7 The noise level of the equipment shall comply with the "Hygienic Standard for Design of Industrial Enterprises". The noise level at the level of 1.0m and the height of 1.2m from the pump casing should not exceed 85dB (A). 3.2.8 vacuum self-priming pump group maximum vibration dual-pump amplitude limit, vibration measurement methods and requirements should be consistent with the existing relevant standards.
