Operating manual liquid ring vacuum pumps and compressors series TRH - TRS - TRM - TRV - SA & Systems type HYDROSYS - OILSYS
6
4.1 - PRINCIPLE OF OPERATION
(See figure at side)
The aspirated gas enters the pump chamber A-B via the pump suction flange. The gas is trapped between 2 impeller
vanes. The impeller rotates eccentrically in relation to the centreline of the liquid ring that, by centrifugal force, assumes
the shape of the impeller casing. The progressive change of volume between the 2 vanes, the impeller hub and the
liquid ring first creates a vacuum and then a compression of the gas in the B-C area till the gas is discharged, together
with a portion of the liquid, through the discharge port C-D. The lost liquid must then be replenished.
4.2 - SERVICE LIQUID PROPERTIES
For a good operation the liquid ring pumps must be supplied with a service liquid which is clean, non abrasive and free
of any solids.
The service liquid temperature should not exceed 80°C and the gas handled should be maximum 100°C; the liquid
density should be between 800 and 1200 g/dm
3
and the viscosity should be less than 40 cSt (the pump performance
will change if the service liquid has properties different than those of water at 15°C). All engineering data is based on
the use of 15°C as service liquid, see chapter 19 for additional information.
Contact POMPETRAVAINI before using liquids with properties outside the ranges listed above.
In case the metallic pump wetted parts come into contact with aggressive liquids it is recommended to stick to the
following limitations:
- pH limit for cast iron and ductile iron
≥ 6
- pH limit for stainless steel
≥ 2,5
The above values are approximate and refer to ambient temperature. It is recommended to contact POMPETRAVAINI
for doubts, particular conditions or in case different materials are used.
4.3 - PUMP MODELS AND TABLES FOR MATERIAL OF CONSTRUCTION
On the pump nameplate are printed the pump serial number, the year of manufacture and the pump model. Refer to the
following example for understanding the coding of the pump model.
Every letter or number in the pump model designation has a specific meaning relating to the pump design.
Example of pump model number:
T R H C 80 - 750 / C - M / GH - Z
T
Manufacturer POMPETRAVAINI
C
C = Shaft sealing by mechanical seal
R
Liquid ring pump
B = Shaft sealing by stuffing box
M and V = Single stage pump with high vacuum
M
Monoblock design with motor flange
H
S
= Single stage pump with medium vacuum
(upon request)
H
= Two stage pump with high vacuum
GH
Material of construction
C
Revision of hydraulic design
GH - F - RA - A3 (see following table)
80
Ø Flange size (mm)
Z
Special design
750
Nominal capacity in m
3
/h
T R V X 100 7 / 1 - C / A3 - M / Z
T
Manufacturer POMPETRAVAINI
1
Constructive project number
R
Liquid ring pump
C
Shaft sealing by mechanical seal
V
M e V = Single stage pump with high vacuum
A3
Material of construction
X
Stainless steel hydraulic plate version
F - RX - A3 (see following table)
100
Ø Flange size (mm)
M
Monoblock design with motor flange
7
Nominal size rate
Z
Special design
STANDARD materials of construction
VDMA
Description
GH
F
RA
A3
106
Suction casing
Cast iron
Stainless steel
AISI 316
107
Discharge casing
137
Intermediate plate
110
Centre body
210
Shaft
Stainless steel AISI 420
147
Manifold
Carbon steel
357
Bearings & M. S. housing
Cast iron
230
Impeller
Bronze
Ductile iron
Stainless steel AISI 316
For additional details regarding standard or special materials contact POMPETRAVAINI.
Models for systems HYDROSYS and OILSYS are made out of a number which indicates the system size, followed by
the pump model number which is fitted in the system.
(ex.: HYDROSYS 5
– TRHB 50-420/C – M / GH).