JB/T 8644-2017Single screw pumps (English PDF)

3.1 Model and expression methods

Five groups of Chinese phonetic alphabet and numbers can be used to indicate the model of the pump, consisting of pump type, structure, installation type, purpose, flow rate and pressure parameters.

3.2 Examples of labeling

Example 1:

The horizontal single screw pump with the nominal diameter of the rotor of 15 mm and with a standard lead series for transporting food and medical media is labeled as follows:

GS15-1

Example 2:

The vertical single screw pump for marine use with nominal diameter of the rotor of 35 mm and with two standard lead series is labeled as follows:

GUC35-2.

Example 3:

At 200 r/min, the theoretical flow rate Q = 2 m3/h. The single screw pump, with the maximum pressure of P=0.6 MPa and with a long lead, for transporting corrosion resistant medium is labeled as follows:

3.3 Rotating direction

Seen from the driving end, the pump rotates in counterclockwise direction. In case of any special requirements from the user, the pump shall be manufactured according to the contract confirmed by both the supplier and the purchaser.

3.4 Basic parameters

Pumps are divided into five grades according to flow rate, as shown in Table 1.

Table 1 Classification of pumps

Grade Theoretical flow rate per 100 r Volumetric efficiency etav Efficiency of pump eta

L No load Rated pressure

Mini-sized <=10 0.96 0.65 0.55

Small-sized >10~50 0.96 0.70 0.64

Middle-sized >50~200 0.96 0.75 0.68

Large-sized >200~800 0.97 0.81 0.73

Extra-large-sized >800 0.97 0.86 0.77

In the table, the test medium of efficiency index is clean water at 20°C, and the pump speed is the data under the relative sliding speed of stator and rotor at vgm=4 m/s. When the pump is integrated with the driving mechanism and cannot be disassembled, the efficiency of the driving mechanism shall be taken into account in measuring the total efficiency of the unit.

3.5 Design maximum speed

The design maximum speed of the pump is determined according to the relative sliding speed of the stator and rotor vgm=4 m/s: the design maximum speed of different types of pumps varies. The above speed is only used for assessing various indexes of the pump during type tests with clear water, and shall not be used as the actual speed. See Annex A for the speed range of the pump when transporting different medium.

4.1 General requirements

The pump shall meet the requirements of this standard, and shall be manufactured according to the product drawings and technical documents approved through specified procedures. While considering the requirements of this standard, special requirements from the users (if any) shall be indicated in the order and the pump shall be manufactured according to the contract confirmed by both the supplier and the purchaser.

4.2 Efficiency of pump

The volumetric efficiency of the pump shall meet those specified in Table 1 of this standard. Under the condition that the power tolerance of pump meets the requirements of JB/T 8091, the efficiency of pump shall meet those specified in Table 1 of this standard, and the lower tolerance limit is 95 % of the specified value. Under the condition that both shaft power and efficiency reach the standard, the lower deviation of pump flow rate shall meet the requirements of JB/T 8091, and the upper deviation shall not be controlled.

4.3 Conditions for medium transported

The pump shall be capable of continuous normal operation under the following conditions for medium transported:

- - the temperature is less than or equal to 80°C, and the special stator can reach -20°C~150°C (otherwise agreed by both the supplier and the purchaser):

- - the pump is allowed to transport medium containing solid particles and fibers. The maximum volume fraction of solid matters shall not exceed 40 %, the maximum particle diameter shall not exceed the eccentricity of the rotor, and the maximum fiber length shall not exceed 40 % of rotor pitch.

4.4 Marine conditions

The pump shall be capable of working reliably under the following marine conditions:

- - periodic rolling of 22.5°;

- - pitch of 7.5°;

- - continuous heeling of 15°;

- - continuous trimming of 15°.

4.5 Vibration level evaluation of pumps

The vibration value of the pump is determined by the following conditions:

- - the pump are divided into four categories according to the theoretical flow rate of pump:

Category I: theoretical flow rate q <= 10 L at 100 r (mini-sized pump):

Category II: theoretical flow rate 10 L 200 L at 100 r (large-sized or extra-large-sized pump).

- - the vibration level of the pump is divided into four levels: A, B, C and D. Among them, A, B and C indicate acceptance and D indicates rejection.

- - the evaluation methods for vibration of pump shall meet those specified in Table 2.