World Applied Sciences Journal 18 (8): 1088-1094, 2012
ISSN 1818-4952
© IDOSI Publications, 2012
DOI: 10.5829/idosi.wasj.2012.18.08.2262
Controlling the Water Pressure in the Pressure Control
Networks Using a New Automatic Pressure-Reducing Valve
H.R. Lotfizadeh, H. Barza and M. Abdevalipour
Department of Civil Engineering, Islamic Azad University, Ilam Branch, Ilam, Iran
Abstract: Increase in urban water networks, network management is one of most important problem in which
the parameters of the network pressure and leakage at night in search of networks and connections will be worn.
Given that the urban water networks with more than 30 years old have been worn and is part of the network and
still have not replaced the night of exhaustion and pressure leakage is due to increased consumption. Network
Management in day and night in order to pressure, pressure-reducing valve was designed and built automated.
In order to reduce demand hours (night) to minimize automatically pressure and increasing pressure on
consumers can be provided for the maximum allowable pressure. The pressure-reducing valve on the network's
performance is such that the input by a pilot pressure to a constant pressure at the output decreases. If the
pressure is 6 bars pressure-reducing valve can be input by a pilot pressure to 3 times reduced and the pressure
will be night and day, 3 times a night if not need this pressure will cause a leak. Pressure-reducing valve built
in this research can be proposed to minimize the pressure in the night and day in different time with different
pressure curve of the network will deliver.
Key words: Urban water networks
Network pressure and leakage
INTRODUCTION
According to the analysis of water networks profile,
flow rate and head tube are unknown at the nodes.
It should be possible for all phenomena occurring in the
water supply network [1]. Logical study of these
phenomena as well as be able to provide answers for the
unknown fact in accordance with the offer. Answers lead
to more accurate results than utilizations are correct.
Phenomena that occur in water distribution networks
include leaks and broken pipes should logically be
studied and analyzed. Check for correct function of these
events to see what these are factors that contribute to
these factors, presented a method for reducing network
[2-5]. In these models is assumed that the flow rate output
is designed for consumers, always prepared and fixed.
Research in the last two decades has shown that the
outflow rate of virtually every node in the node is
proportional to the pressure and flow-based methods to
prove the efficiency, especially in critical situations in
the hydraulic analysis of the water will not be networks.
Due to unexpected changes such as fractures or broken
pipes and valves, pumps, resulting in excessive pressure
drop than the rate for consumers greatly reduced and
Pressure-reducing valve
even some nodes will not be able provide any water [6, 7].
For this purpose, it is necessary to use flow relationships
- the demand-related pressures considered. One of the
most important problems in a network there are leaks in
the network. To combat this scourge must be able to
estimate the leakage in the network, then attempted to
reduce it. Actually, cause leaks in the network, wasting a
large percentage of water is distributed. Additional costs
that the company responsible for supply, transport,
refining, pumping, storage and distribution of water is
likely to be one of the damaging effects of leakage.
Moreover, in cases where there is water shortage crisis is
more serious problem. Water companies to reduce leakage
are often the first step towards replacing the old tubes are
in the network. This process was time consuming and
cost effective than replacing all the pipes in a short time
and financial resources is not possible. Irrigation systems
for proper management and proper planning is needed
with regard to the urban water supply and water
distribution networks, pressure and flow values always
apply to various demands of consumers, including
domestic, industrial, agricultural etc. During the day, be
accountable. A type of water supply network analysis,
demand analysis, the analysis cannot prove that this type
Corresponding Auhtor: H.R. Lotfizadeh, Department of Civil Engineering,
Islamic Azad University, Ilam Branch, Ilam, Iran.
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of network reality shows, especially in critical situations.
This type of analysis only works in normal mode [1].
Other type of demand-based method can be based on the
pressure the network behavior of the model. The tank
should be kept in mind when considering the balance of
time in bed or static or dynamic analysis is performed
[8-11]. In this study discharge pressure is assumed to be
variable and then providing an automatic pressurereducing valve designed by the research team and
consider an arbitrary time intervals can be changed
according to the needs of consumer’s pressure. On the
other hand, high consumption period (peak usage) added
pressure and low consumption period (midnight to dawn)
pressure to a minimum, the second section, including
review of technical literature Pressure-reducing network
is fluid valve. Relations used to compare the strengths
and weaknesses of each are discussed. In the third
section, methods and components used in this research
pressure-reducing valve and water supply networks and
relationships - discharge pressure and other parameters
related to network components needed to be reflected. In
the fourth section, with the valve installed in a real
network equipment performance and accuracy of its
operation is demonstrated. Finally, in the final section of
the paper, we summarized and conclusions.
Types of Pressure-Reducing Valve: Pressure
management is important issues of global water industry.
However, in spite of extensive research and experience on
domestic and international corporations, government
agencies of such experiences. We are in control, low
interest and unfortunately, the greater part of project and
the water industry, large-scale hardware is concerning this
and leaks in networks that are already in some provinces
are more than twenty percent without increasing power of
new water sources, horizontal accountability plans
increase. Mankenberg International Co., Inc. Org and
mechanical valves Pressure-reducing water developments
have had a good talk but nevertheless managed to solve
because they can not push the valves installed on a
constant outlet pressure is set (Figure 1).
Solenoid valves type Danfoos electric company and
can only act as zero and one. Electric Solenoid valve so
that the pressure to zero at night to reduce the possibility
of this problem is that at night there is no minimum
consumption (Figure 2).
Watts the most advanced international companies
in a variety of valves between the aforementioned
companies have marketed but have been unable to
solve the problem of automatic pressure management.
Fig. 1: Normal pressure-reducing valve
Fig. 2: Different parts of Solenoid pressure-reducing
valve: 1) Opening and closing valve, 2) - filter, 3)
one-way valve, 4) Solenoid
Some products include valve, water level control tank,
Solenoid valve closed, the valve float off and normal
pressure-reducing valve. Solenoid valve in open and
closed is shown in Figure 3.
Theory
Water Consumption in the Network: The amount of
water that enters the network and can be used can be
divided into two categories:
Controlled Consumption: The amount of water entering
the network is part of the consumer is placed. Each share
of the total water consumption of the controlled input is
more network, network design and performance in order
to create favorable conditions for taking the step.
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This relationship,
the
relationship
between
pressure and flow at each node for a specific
period covered The relationship between flow
direction can not be a good indicator - if the
pressure at each node [1].
Continuous relations: These relationships have been
between flow rate- pressures at each node for the entire
range and continue to consider. Germanopoulos [2]
proposed the following relationship:
 H j − H min


j

− cj  des
min  


−
H
H
req
avl
j
j


Qj
Q j 1 − b j e
=




Fig. 3: Solenoid Valve opening and closing
Here it is necessary that the two concepts are defined:
the flow rate demand (Demand) and the discharge or
outflow (Outflow). Discharge flow rate or flow rate at each
node is a node in the head based on head and compare
this with the minimum required head is obtained. This
amount may be less than or equal to the amount of
discharge in each node wanted to be in place. Network
design is based on the available flow or output node, the
node closer to the flow demand. The network condition is
closer to normal conditions.
Uncontrolled Consumption: This amount includes the
portion of the water entering the network is out of the
cycle without the consumer being consumed or the
amount to be paid.
Relationship Between Pressure and Flow in Demand
Nodes: Over the past decade, various researchers have
tried on was the relationship between flow rate and the
pressure in the receiver node is in its offer. Relationship
can be controlled with the use of them to be divided into
two general categories:
Discontinuous Relations: The earliest expression of
the relationship between discharge and pressure
at each network node in this group are presented.
(1)
where Q avl : is flow in which the nodes j, Q req : demand
j
j
rate at node j and Hj: is the head node j.
Absolute minimum in the head so the head
node is smaller or equal to the amount of any
current does not pass. Where the value is not
enough information in hand, is usually considered
to be equal to the height of land. Required minimum
design head, the heads of these amounts do not
have the ability to satisfy consumer needs. This amount
is usually less than 30 meters above the base level is
considered. Empirical coefficients of the equation
and their values are 10 and 5 respectively. Also the
relation flow rate- pressure of the appropriate
algorithm to use is required. According to the research
Tabesh [1], among the algorithms Gupta, Bhave [2],
the manner in which the flow - pressure at the nodes and
term leak directly in the continuity equations in the node
set and in all replicates of Network Analysis, it used the
best response between models based on pressure and the
answer is having [1, 2].
Leakage: The costs of water distribution network at a
cost of pumping and water treatment is injected into the
network. The amount of water that is produced
entirely in the network always been available to
consumers and some of it is wasted in the production to
consumption. This water loss is mainly due to
leakage and unauthorized links causes water out of the
cycle and reduced water. Wastewater companies to
impose heavy costs will be. This time also limits the use
of water resources, the shortage is more serious
and need to deal with various aspects of the spill will tell.
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Unfortunately, this problem has always existed in
urban water distribution network and sometimes
includes the percent of total water entering the
network is extensive. For example, in England,
between 10 to 50 percent of the total amount of water
unaccounted for water injection and the average was
24 percent [3]. In another report, this amount of between
5 to 55 percent is approximated [4]. In Malaysia, Sweden
and Brazil, the amount of leakage, respectively 40, 25 and
25% have been reported [5]. In Iran, the average amount
of unaccounted water in the entire country is about 30
percent. I should note that the studies are usually
between 40 to 70 percent of total water unaccounted for
water loss or leakage to be physical. Factors such as
pressure in the pipeline leaks in the network, the traffic
route, aging pipelines, connection quality, water quality
and the bed is made.
Leak and Pressure: As mentioned above the pressure of
the pipeline is leaking. In practice, the network can be
seen that with the pressure well reduced the leakage in the
network and thereby reduce the frequency of burst pipes
network [6-8]. Among all the factors in the leak, pressure
most efficient, easiest and most economical solution is to
reduce leakage. Between leaks - pressure based on field
studies performed in the United Kingdom Water Research
Centre is obtained. As previously noted, leaks in the
network is not only a function of pressure, so that the
vertical axis represents the leakage index is larger than the
actual spill volume in the network. Leakage index is the
ratio of pressure to leak in a pressure leak. The horizontal
axis of this curve at night MV (AZNP) is. AZNP is the
mean pressure within the system that occurred at night
and pests affected area is hydraulic and topographic
changes. Therefore, the position of the night when
demand is selected because it had the lowest and the
network can be represented well for network leaks.
Therefore, it can be concluded that the pressure in the
high range can lead to a significant reduction in leakage
compared to the same amount of pressure in the low
range.
Pumps: The head - discharge curves of the pumps can be
inherit a share that will be remembered as the pump
characteristic curve, stated:
H P = H j − H i = APQP 2 + BPQP + CP
(2)
AP, BP, CP Values are fixed and are determined
experimentally. The pump manufacturer usually provides
these values. Where HP Head produced by the pump, QP
Flow generated by the pump.
The Amount of Leakage in the Network:
Considering the above mentioned conditions and
the current lack of information and ease of use,
the study of the relationship Germanopolous [2] is used
to determine the amount of leakage in the network:
(
)
=
QL,ij Cl Lij 0.5 H i − GLi + H j − GL j  1.18


(3)
Leakage in each node is calculated as follows:
QL, j = 0.5
∑ QL,ij
(4)
i∈I
QL,j leakage in the node j and I Number of connections
leading to node j.
Experimental
Valve Pressure-Reducing: Fluctuations in a distribution
network of drinking water, during a night, include a
challenge that can be converted into opportunities.
During the interval between twelve at night to six in the
morning that consumption is virtually zero network out of
orbit in twenty-five percent of the time pressure at least
equal to one half to two times a day, has a leak can be
reduced. In the inlet, pressure is defined for automatic
pressure-reducing valve by the boards of the converter
output. This control system for an electric (AC or battery)
and adjustable (time pressure and output) with the
information network in the downstream pressure sensor
and pressure applied by a command to increase or reduce
the outlet pressure regulator. Other electric equipment in
the valve of a gearbox with four different tests and change
the RPM of the gearbox and electromotor ensure that any
impact on the upstream network does not. Performance
management system can be briefly stated thus the
pressure, which reduces time spent in the control system
automatically reduces the pressure and at a minimum need
for keeps. Moreover, the timing of intake, with the system
provides pilot pressure to the desired command (Figure 4).
Typically consume higher in early morning and
evening and at midnight is less. The system pressure
must fulfill the requirements for high consumption users
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Fig. 4: The optimal consumption
Fig. 5: The input and output pressure during the night and day
are high, while the pressure is higher than the amount
required to be low during the night hours. In high-use,
hours and the pressure at the beginning of each region
should be high so the water pressure drops due to flow
over the tubes. Since the problem is caused by low
consumption hours, with reduced water flow, pressure
drop due to the lost, the pressure inside the pipeline
pressure is equal. The water pressure in the pipe pressure
is much more than they can be used for fill. High-pressure
water, creating a permanent change in one hand and
fatigue, causing premature wear joints, cracks, leaks
and burst pipes provides severe. If the leakage rate of
pre-created gaps and wasted water and energy levels also
add to the above, the amount of damages will be difficult
to change water pressure. The old management system
pressure, water pressure at the beginning of each region
was kept constant by the pressure control valve. One of
the most important problems in these systems is the lack
of feedback from the network. Despite the importance of
having a system with feedback from the network, the
immediate decision-making and control water pressure
must be specified (Figure 5).
Network is a real need for performance evaluation
purposes. It is necessary that at least a few days testing
the pressure changes occur in a pipeline based on the
parameters to be measured.
Studied Network: Ilam drinking water network has 8 zone
of compressive pressure fluid valve that is running in the
breaker zone Tuesday and four were installed in the
network due to the high altitude zone of 60 meters in each
half of the zone has been designed and tested in a It took
half of the zones.
Designed Automatic
Pressure-Reducing Valve:
In order to model the behavior of pressurereducing valve must be a node in the network a
little extra valve after the primary node can be defined.
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Fig. 6: Automatic pressure-reducing valve downstream pressure sensor feedback control board and motor
3.5
3
2
1.5
Pressure (Bar)
2.5
1
0.5
0
90
80
70
60
50
40
30
20
10
0
Time(H)
Fig. 7: Pressure downstream of the outlet valve installed in the evening hours
This node has its head in the valve in pressurereducing valve is considered. Pressure-reducing
valve show the ability to be placed in the network.
Figure 7 shows the head in the pipe downstream of
the PRV. However, referring to Figure 7 can be seen that
only when the pressure-reducing valve will do their
duty to the electronic board to give him command of the
keys installed on the pension board monthly or
quarterly be modified or are the. Pressure-reducing
valve with electric actuator for a period of twenty
days on the zone lines were installed and Results Four
Ilam water system pressure downstream of the outlet
valve and the sensor feedback system in place as
boarding was recorded following the curve of the
results show. Twenty days of the completion of the
test car battery is installed. The important point
precision pressure
sensor
downstream of the
control system was defined as 0.1 Bar to the fluctuations
of less than one tenth of the load control system,
does not react because of the severe depreciation of its
energy consumption by motor valve engine uses the
incoming electrical shocks. Experts also very well attend
once the valve from rural to urban Abfa regional water
experts Ilam was installed at the pumping station zone,
three cities and a pilot test was carried out through a
bypass line.
CONCLUSIONS
The aim of this study was to analyze the demand
for urban water supply networks based on the pressure.
The effect of leakage on water distribution networks is
required, the formula that makes the connection to leak
pressure, discharge pressure in the continuity equations
with the relations between nodes, can be integrated.
This relationship is assumed that the leak in the pipe
length, which is distributed equally according to the
network needs to investigate the leak is in place, in
this simple premise of this software is used. As mentioned
in the hydraulic analysis of water supply networks
must be possible for all phenomena occurring in the
network, including leakage, fire flow analysis is logical,
etc., to obtain answers in accordance with reality.
Considering that the purpose of HDSM pressure flow
relationships to address water supply network analysis,
was used. Unlike current methods, this method DDSM
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output node regardless of the amount of pressure for
constant consumer considers the possibility of importing
water phenomena occurring in networks that are output to
reduce the flow of hydraulic network analysis provides.
As mentioned in HDSM, relationships need to
communicate with the discharge outlet pressure based
on the fact that in all cases takes there. Relations Wagner
et al. [8] as the best and most complete link between the
output current with regard to continuity of pressure in the
upper and lower limits for output currents were
considered. Although the scientific basis of Wagner et al.
[8] as well as content in the second and third seasons
seems that, this method provides a more reliable better
and answers. However, for better judgment in this regard
is the need for more extensive field studies. Considering
the relations between nodes in the heads of heads and
heads of at least the required minimum, compare the
amount of current output is determined according to the
current request. The head ties - During the pipes and
pumps and valves of the Hazen–Williams equation used
the psychological experiments concerning water supply
networks, the results of sufficient accuracy and output
currents and pressure relationships in combination with
the continuity equations well-done and hydraulic analysis
of high-speed network will. Each of the other elements
such as hydraulic pumps and valves have their own
equations indicate that the final formulation of continuity
equation in each node are reflected in there. Solving
equations for water supply networks, according to their
nonlinear, numerical and approximate Newton-Raphson
method for solving the equations H with high
convergence and head ties - the members are related to
the Jacobian matrix flow easily, use has. Finally, some of
the benefits of automatic valve Pressure-reducing made
include - the intelligent network pressure on Boards.
The pressure capability of the network at night to reduce
nocturnal leakage. The ability to increase the maximum
allowable pressure in the network at peak hours. Has the
advantage of working with the AC and DC battery.
Complete insulation performance when the pool is due to
flooding. Reset the keyboard. The ability to install a data
logger to record the pressure boarding.
REFERENCES
1.
Tabesh, M., 1998. Implications of the pressure
dependency of outflows on data management,
mathematical modeling and reliability assessment
of water distribution systems, PhD Thesis,
Dept. of Civ. Engrng., University of Liverpool,
England.
2.
Germanopoulos, G., 1985. A technical note on
the inclusion of pressure dependent demand
and leakage terms in water supply network
models, Civil Engineering Systems, 2, September,
pp: 171-179.
3. Tabesh, M., T.T. Tanyimboh and R. Burrows, 2002.
Head driven simulation of water supply networks, Int.
J. Engrng., Transactions A: Basics, 15(1): 11- 22.
4. Tanyimboh, T.T., B. Tahar and A. Templeman, 2002.
Pressure-driven modeling of water distribution
systems, Proc. of the IWA 3rd World Water
Congress (Enviro 2002), 7-12 April, Melbourne,
Australia.
5. Lambert, A., 1997. Managing leakage: Strategic for
quantifying, controlling and reducing water losses,
based on analysis of components using BABE
concepts, In: Water Pipelines and Network
Management, HR Conference, London.
6. Giustolisi, O. and D. Laucelli, 2007. More realistic
water distribution network design using pressuredriven demand and leakage, Water Management
Challenges in Global Change, Ulanicki et al. (eds.),
Taylor & Francis Group, pp: 177-183.
7. Todini, E. and S. Pilati, 1987. A gradient algorithm for
the analysis of pipe networks, In B. Coulbeck and
C.H. Orr (eds.), Computer Application in Water
Supply, Vo.1 (System analysis and simulation), John
Wiley & Sons: London, pp: 1-20.
8. Wagner, J.M., U. Shamir and D.H. Marks, 1988. Water
distribution reliability: simulation methods, J. Water
Resou. Plan. and Manag., ASCE, 114(3): 276-294.
9. Tabesh, M., A.H. Asadiani Yekta and R. Burrows,
2009. An integrated model to evaluate losses in
water distribution networks, J. Water Resou. Manag.,
23: 477-492.
10. Tabesh, M. and A. Doulatkhahi, 2006. Effects of
pressure dependent analysis on quality performance
assessment of water distribution networks, Iranian
J. of Sci. and Tech., Transaction B: Technology,
30(B1): 119-128.
11. Tabesh, M. and M.R. Delavar, 2003. Advances in
Water Supply Management Proceedings of the
CCWI '03 Conference, London, 15-17 September.
12. Jaumouille, E., O. Piller and J.E. vanZyl, 2007.
Ahydraulic model for water distribution systems
incorporating both inertia and leakage, Proc. of Water
Management Challenges in Global Chang (CCWI
2007), Ulanicki et al. (eds.), University of DeMount
Fort, Leicester, UK, Taylor & Francis, pp: 129-135.
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