ZHG
General
Hydraulic accumulator sets built as parallel systems of several pumps are designed for pumping water, raising water pressure in supply networks, and compensation of hydraulic losses resulting from the parameters of supplied pipelines.
The pumping sets are designed to supply potable water and/or treated utility water without solid sediments at a temperature below 25oC. Maximum operating pressure of the set: 10 bar.
Basic technical data
| capacity |
0,9 ÷ 60 m3/h |
| delivery head |
10 ÷ 90 m |
| pumped liquid temperature |
max 25 oC |
| Working pressure |
10 [bar] |
Main applications:
- High-rise multi-family buildings.
- Public buildings (hotels, hospitals, office buildings, banks, etc.).
- Local pressure accumulation systems.
Product marking structure
| a a |
product classification group (general product name, example: ZH), |
| a1 |
hydraulic accumulator design version (G - Deep-well pumps GBA.2, GBA.4, GBA.5.) |
| b |
type size of applied pump, e.g.: ZHG.1 - a set of GAB.2 pumps, |
| c c |
type size of applied pump, e.g.: ZHG.1.08 - a set of eight-stage
GAB.2.08 pumps, |
| d |
number of pumps in set (from 1 to 9), e.g.: ZHG.1.08.3 - a set of three eight-stage
GAB.2.08 pumps, |
| e1 e2 e3 e4 |
design version of the set. This part of the index is covered in the section about the set design, |
| h |
type of control. This part of the index is covered in the section about the set control system types. |
| i i i |
factory designation of the control system. It is issued at the stage of quotation or order confirmation once the function and operating method of the set have been defined. |
| k |
designation of optional accessories |
| k |
Description |
| 0 |
No extra pump. |
| 1 |
Flush pump. |
| 2 |
Fire water pumps. |
| 3 |
Mixed pumps. |
Construction
The hydraulic accumulator sets are systems of several pumps that usually have the same size and which are connected in parallel to the supply and delivery manifolds by non-return and cut-off fittings. The set pumps are installed on a support structure made of steel sections. The support structure features vibration dampers that allow setting the set directly on floors.
The ZHG hydraulic accumulator sets are based on parallel connections of GAB submersible pumps enclosed in hermetic shells. The number of pumps in the set ranges from 2 to 4. The set designation is specified according to the key listed at the beginning of this catalogue.
The sets of this design version with the pumps running submerged in the pumped medium feature very quiet operation and do not cause a nuisance even if installed in rooms directly adjacent to inhabited rooms.
Pumping units
The ZHG type features GAB submersible pumps. They are multi-stage submersible pumping units with an output ranging from 0.9 m3/h to 15 m3/h and hydraulic rise capacity from 10 m H2O to 90 m H2O, depending on the number of stages.
| Set type |
Pump type |
| ZHG.1 |
GAB.2 |
| ZHG.2 |
GAB.4 |
| ZHG.3 |
GAB.5 |
Support structure
The pumps of the hydraulic accumulator sets are installed on a support structure in the form of a framework made of austenitic steel (e2 = 1 only). The support structure is set on vibration dampers at the installation site. The vibration dampers reduce transmission of vibration to the ground and eliminate the need for special foundation work.
Fittings and manifolds
The manifolds connect the pumps in parallel with fittings. The manifolds, hermetic shells and all connections are made of stainless steel. The manifolds feature pressure gauges and transducers. The delivery manifold also features membrane pressure vessels which minimise the water hammer during starting and stopping of individual pumps. Due to the specific nature of certain serviced facilities (high-rise buildings, multi-family residential buildings, etc.) with variable water consumption, the available pressure vessel capacity ranges from 18 dm3 to 200 dm3.
| It is always possible to customise the solutions to detailed requirements concerning every aspect of the offered set. |
Control
There are several control types for the pumping sets offered, due to the wide variety of applications.
| h |
Description |
| 1 |
Adjustment using a rolling (switchable) frequency converter. The control unit is a microprocessor-based controller. |
| 2 |
Cascade control (on/off). The control unit is a microprocessor-based controller. |
| 3 |
Control by a frequency converter linked to a single pump with all other pumps switched on in a cascade. The control unit is a microprocessor-based controller. |
| 4 |
Control and adjustment with a frequency converter with an onboard controller featuring an application for control over the pumping sets. The control unit is a microprocessor-based onboard controller of the frequency converter. |
| 9 |
Design version according to individual and precise customer requirements. |
Features of the microprocessor controller used in standard ZHG set control systems:
- Pump speed control depending on the delivery manifold pressure (in an FC system, h = 1). The control system maintains a constant pressure or its specified values in a defined interval by switching various pumps on and off, and adjusting the RPM of the pump that is currently connected to the frequency converter.
- Switching the pumping unit on and off depending on the delivery manifold pressure (in a cascade system, h = 2). The control system maintains a constant pressure or its specified values in a defined interval by switching various pumps on and off.
- Starting of successive pumping units in the set (by a frequency converter or directly from the mains, or optionally by a thyristor soft starter).
- Pump running time balancing: equalisation of the usage rate and test running of pumps in a set that provides fire water supply (all identical pumps of the set). In this function the first pump to be started is the pump with the shortest running time or with the longest standstill.
- It also prevents starting of more than one pump at the same time. It is possible to set a time delay after which the next pump in the set will start.
- Stopping and switching the set to standby in periods of zero demand.
- Stopping of pumps at programmed permissible pressure setpoints.
- Adjustment of the system's performance of the supplied pipeline characteristics by discrete adjustment of pressure setting values in relation to the number of running pumps or preset measured flow rate (optional connection to a flow meter).
- Readouts of all measured operating parameters.
- Adjustment of parameter settings in relation to time interval settings (option).
- The control system automatically switches to cascade operation when the frequency converter fails.
- The control system enables switching to manual mode when the controller fails.
Features of the controller software:
- Collection of data about the values measured in the last seven days.
- Memory of all operating state changes of the set with precise event times (storage capacity: 1000 events).
- Collection of data about individual pump running times.
- Export/transmission of data packages over a serial link in an agreed format to external devices (radio modems, phone modems, GSM modems, PCs).
ased on this description of features, an example set code presented above can be developed as follows:
| Z |
H |
G |
1 |
0 |
8 |
3 |
3 |
1 |
2 |
5 |
3 |
2 |
0 |
4 |
0 |
A hydraulic accumulator set with three GAB.2.08 pumps and the standalone control cabinet, tapped manifolds, a control system with the frequency converter connected to a single pump and other pumps started directly from the power network in cascade. Type UZS 8.01 control system. The set is without any accessories or extra pumps.
Control cabinet
The control system is installed in a cabinet with an IP54 enclosure. The cabinet size depends on the hydraulic accumulator set size. The cabinet sizes are listed in the set dimensioning tables. The cabinet structure is metal with powder coating. The cabinet has an independent support structure (vertical frame) that accomodates any installation orientation. One end of the structure rests on vibration dampers and the other is fixed to the support structure of the pumps.
The control cabinet front door features:
- The controller ZZ wa front panel with the operator's control panel;
- Operation mode selector switches for individual pumps (operation mode switching: hand/automatic);
- Start and stop switches for individual pumps;
- Operating status and failure alarm indicators.
- "Power Failure" indicator;
- "Dry run" indicator.
The side panel of the control cabinet features the main switch.
| Dry run protection |
|
The set pumps are protected as standard from dry running by means of conductivity probes placed in hermetic coats. In addition, a set that is operated with an open reservoir can feature float switches or a system of conductive measurement probes, or work with a hydrostatic probe that controls the reservoir filling. In this version the set has no pressure transducer on the supply manifold. A set operated on a water supply system has the pump dry run protection with the aforementioned conductive measurement probes and a pressure transducer on the suction/supply manifold. The available optional protection includes an LCA pressure switch installed on the suction/supply manifold of the set.
|
Installation site considerations:
- The room area should enable installing the hydraulic accumulator set with clearances that enable free access to individual components.
- The ambient temperature at the installation site should be between +5oC and + 40oC.
- The room should feature a ventilation system with an air exchange rate of 1/hour or higher.
- Due to the foundation of the set on vibration dampers with levelling, no extra foundation works are necessary for the installation.
- The room floor should have a slope towards floor drains for effective water discharge from the installation site. The running hydraulic accumulator set must be protected from flooding with water.
- If the set is fed by an open storage reservoir, the hydraulic accumulator set should be located to ensure a minimum static flow of 1.0 m at the set connection point. Otherwise contact the manufacturer to select and install a suitable flooding adapter.
Features of sets
- The characteristics of the pumps used in the sets meet PN-EN-ISO 9906:1999 Class 2.
- CE Declaration of Conformity.
- The pumps and the set structure are made of corrosion and water resistant materials.
- The installation style in the hermetic shell ensures quiet running of pumps (40 dB maximum) which enables installation directly in basements of serviced residential buildings
- without any additional sound-proofing of rooms.
- There are no external movement seals.
- The hermetic installation allows operation in difficult ambient conditions, i.e. high humidity, high dust concentrations, or risk of flooding (a pump room).
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