Treatment and maintenance equipment

Treatment and maintenance equipment

A guide to identifying, selecting and using filters, filtration pumps, anti-algae materials, injection equipment, valves, strainers and consumable parts.

The beauty of the fountain depends on the quality of the water that circulates in it. Water pollution can reduce the clarity of the pool, change the shape of the nozzles, cover the surface of the lights and increase the cost of cleaning and repairs. Therefore, the purification equipment should be selected from the beginning of the design, together with the demonstration equipment.

The water fountain filtration system has three different tasks: particle separation, microbial pollution control, and water chemical regulation. A mechanical filter cannot perform all three tasks alone. Also, the clarity of the water is not a sufficient reason for its suitability in terms of health.

This chapter examines seven groups of equipment, according to the book's initial list. Computational relationships are provided to explain the selection method; The values ​​of the examples are hypothetical and the performance specifications of each project must be adapted to the actual conditions, manufacturer's documents and the requirements of the responsible authority.

62–1. Basis for selection of purification equipment

Before choosing the model and capacity of the equipment, the type of operation must be determined.

This separation should correspond to the actual use of the space. CDC guidance emphasizes that if people enter a decorative water feature, it should be managed like a water play area or be prevented by appropriate measures. This guide is an international reference and does not replace local project requirements. Manual for using interactive water fountains, CDC ^[425]

A non-contact water fountain also requires a water quality management plan. Sediment, biological layer, water temperature, water retention and disinfection status are important factors of pollution control in decorative fountains. Guide to Legionella Control in Decorative Fountains, CDC ^[426]

To start the design, at least the following information should be registered:

• The volume of operation of the reservoir, reservoirs and related parts of the circuit;

• The quality of incoming water and the possibility of entering soil, leaves and runoff;

• Display activity hours and necessary hours for purification;

• sensitivity of nozzles to particles and clogging;

• Installation space, maintenance access and sewage exit route;

• Ability and number of operating staff.

62–2. Filters

62-2-1. What does the filter do?

A mechanical filter collects particles by passing water through a bed or separator surface. Its performance depends on the size and nature of the particles, flow rate, bed condition and washing method.

Phrases such as "suitable for a 100 cubic meter pond" without mentioning the flow rate, pollution load, and operating conditions are not sufficient for engineering selection. Also, the ordinary sand filter does not remove the hardness and dissolved salts of the water; The issue of sediment caused by incoming water should be investigated separately.

62-2-2. Main filter groups

In conventional cartridge filters, cleaning is done by removing and washing the element, and the sand filter backwash method should not be extended to them. For example, in the introduction of the Clean & Clear Plus family, Pentair mentions the absence of the need for backwashing. Pentair cartridge filter ^[427]

62-2-3. Calculation of the initial flow rate of treatment

The basic relationship for the theoretical circulation of water is:

$Q_f=\frac{V}{T}$

in which:

• $Q_f$: treatment flow, in cubic meters per hour;

• $V$: water volume under treatment, in cubic meters;

• $T$ : theoretical circulation time, in hours.

The turnaround time should be derived from the project design basis. This time does not mean that all water components pass through the filter at one time; Mixing, short circulation paths and low flow points affect the result.

Educational example

For a hypothetical decorative fountain, we consider the water volume to be $60$ cubic meters and the hypothetical circulation time to be $3$ hours:

$Q_f=\frac{60}{3}=20m^3/h$

The number of three hours in this example is not a general recommendation for fountains, especially interactive ones.

For a granular bed filter:

$A=\frac{Q_f}{v_f}$

In this regard, $A$ is the bed surface and $v_f$ is the rate of water passing through the surface unit. If, just to continue the example, the default rate $25m/h$ is chosen:

$A=\frac{20}{25}=0.80m^2$

For circular substrate:

$D=\sqrt{\frac{4A}{\pi }}\approx 1.01m$

This diameter is the geometric result of the example. In addition to the surface, the selection of the final product depends on the bed depth, media type, flow distribution, allowable pressure and washing capacity. The method of determining the level from the flow ratio to the filtration rate is also explained in the Pentair training manual. Pentair pump and filter base guide ^[428]

62-2-4. Washing the filter

At start-up, the inlet pressure, outlet pressure and actual flow rate are recorded:

$\Delta P=P_{in}-P_{out}$

The change in pressure difference should be checked at comparable flow rates. As the pump revs change, a simple comparison of today's and day one's pressure can be misleading.

Washing time is determined based on the manufacturer's instructions, pressure drop increase, flow rate decrease and water condition. Poor backwash does not remove dirt well; Excessive current may also eject media from the reservoir. Pentair's THS Filters Guide addresses both situations in troubleshooting. Guide to THS filters ^[429]

Approximate volume of water used for one washing step:

$V_{bw}=Q_{bw}\times \frac{t_{bw}}{60}$

If the assumed flow rate of washing is $32m^3/h$ and its duration is four minutes:

$V_{bw}\approx 2.13m^3$

The consumption of the rinsing step and other steps are added separately. The discharge capacity of wastewater and compensation water must be compatible with this consumption.

62-2-5. Examples introduced in builders' sources

In the filtration section of the GSO website, the following products have been introduced:

In the introduction of the S144, it is mentioned that it comes with a one-horsepower Power-Flo LX pump. This information is the primary ID of the product; From the name of the model or the power of the engine, it is not possible to conclude the actual flow rate of the circuit or the proper volume of the fountain. Pump curve, filter level, pressure drop and backwash conditions should be obtained for final selection. GSO filtration equipment ^[430]

An international example is FiltoClear 3400 from OASE. In the American version of this product, the maximum flow rate is 9000 liters per hour, the maximum working pressure is 0.2 bar, and the UVC power is 24 watts. The electrical specifications are the same as the 120 V and 60 Hz version; Therefore, when preparing, the appropriate version of the project's power grid should be checked. Specifications of FiltoClear 3400 ^[431]

The declared capacity for the pond and the power of the UVC lamp alone do not confirm the applicability of the device for interactive water fountain disinfection.

6-2-62. The role of UV in purification

UV is a disinfection or biological control step and does not take the place of a particle collection filter. It is not enough to choose it based on the wattage of the lamp; Flow rate, UV transmittance of water, sheath condition, lamp life and validated reactor performance are important.

Manufacturers such as ProMinent introduce validated UV systems with independent application ranges and performance specifications. This difference indicates that "pond clarifier" and "disinfection reactor approved for specific use" should be evaluated separately. ProMinent UV systems ^[432]

62–3. Purification pumps

62-3-1. The difference with the display pump

The display pump works to create the height, shape and movement of the fountain; The purification pump must provide the necessary flow for the purification process.

If the purge is fully dependent on the display program, stopping the display may also stop the purge cycle. Therefore, the schedule and hydraulic arrangement of these two circuits must be designed in harmony. The independence of the treatment circuit in many projects simplifies the operation control.

62-3-2. Selection criteria

The selection of the pump should be based on the required flow rate in the actual head of the circuit. The total head includes the effective level difference, the drop of pipes and fittings, strainer, filter and equipment installed in the track.

For design, three situations should be considered:

1. Clean filter and the highest possible flow rate; 2. The filter is at the threshold of washing and the lowest acceptable flow rate; 3. Backwash mode, if using the same pump.

A pump that is in proper filtration mode does not necessarily provide the required flow for backwash.

62-3-3. Power estimation

Hydraulic power:

$P_h=\rho gQH$

In this regard, $Q$ must be entered in cubic meters per second. For hypothetical discharge $20m^3/h$ and hypothetical head $12m$:

$P_h\approx 654W$

If the total efficiency of the pump and motor at the same point is hypothetically 0.60:

$P_{in}\approx \frac{654}{0.60}=1090W$

This estimate does not replace the actual pump curve. Motor selection and load control should be done for the operating range.

62-3-4. Installation and service requirements

The treatment pump must be able to be separated, drained and accessible for replacing the seal. Check the condition of suction, air intake and filter pressure drop. Increased clogging in the suction can disrupt the pump's performance; Enlarging the engine is not the solution to this problem.

In the variable speed system, the minimum permissible speed must be compatible with the minimum flow of filter, disinfection and injection. Reducing power consumption should not eliminate necessary process flow.

62–4. Anti-algae material

62-4-1. Control the cause of growth

Before choosing an anti-algae agent, the condition of soil and organic matter entry, floor sediment, low flow points, treatment quality and cleaning schedule should be checked. Repeated addition of material, without addressing these conditions, can increase the cost of operation and make the problem recurring.

62-4-2. Necessary information to choose

For each proposed article, the following should be recorded:

The title "anti-algae" alone does not mean a disinfectant suitable for general contact.

For example, OASE offers AquaActiv AlGo Fountain Concentrate for algae, odor, and scale control in the indicated application and emphasizes reading the label and product information. The use in each fountain should be adapted to the same range of use. OASE fountain care product ^[433]

62-4-3. Amount of consumption and registration of operations

The consumption amount should be derived from the actual water volume, product recipe and water management plan. Starting dose, maintenance and corrective action may vary.

Registration of the substance, amount, time of consumption, volume of water and the result of the subsequent measurement, provides the possibility of checking the effectiveness. Changing the brand name should also be accompanied by a re-examination of the concentration and dosage.

Different chemicals should not be mixed with each other; Especially the contact of chlorinated materials and acid can produce toxic gas. Chemical Injury Prevention Guide, CDC ^[434]

62–5. Injection equipment

62-5-1. System components

An injection system, depending on the material and process, can include a storage tank, metering pump, suction and injection line, injection valve, anti-siphoning equipment, level control and measuring instruments.

Diaphragm or peristaltic pump selection should be done with flow rate, injection point pressure and chemical compatibility. The capacity in liters per hour is not complete information without knowing the pressure and working conditions.

62-5-2. Calculation of injection capacity

For flow proportional injection:

$q_s=\frac{Q_w\times d}{C_s}$

in which:

• $q_s$: injection solution flow rate, liters per hour;

• $Q_w$ : water flow rate, cubic meters per hour;

• $d$: amount of added active substance, mg/liter;

• $C_s$: concentration of the active substance in solution, grams per liter.

In these units, $Q_w\times d$ gives the amount of active substance in grams per hour.

The amount added is not the same as the target residual concentration. The reaction of the substance with pollution, mixing and water conditions have an effect on the result. Therefore, the target concentration should not be related without analyzing the process and keeping the pump constantly on with the same value.

62-5-3. Control and monitoring

Sampling points should be representative of the desired situation. Sensors require washing, calibration and comparison with independent testing.

In automatic systems, monitoring of sample water flow and material inventory is also important. For example, ProMinent introduces the combination of pH and chlorine measurement and control, sample water monitoring, material inventory monitoring and data logging in the DULCODOS Pool Comfort family. This product is an example of an integrated control structure; The choice of its version for the project depends on the application conditions. DULCODOS Pool Comfort System ^[435]

62-5-4. Stop injection in the absence of flow

The command to turn on the pump does not prove the existence of real flow. The injection system should go to safe mode when there is no or lack of circulating flow.

Incompatible material tanks should also have separate leak containment. These two issues are emphasized in the CDC's Chemical Safety Guidelines. Safety of material storage and injection system ^[436]

Flow cut test and injection stop check should be recorded in periodic delivery and service schedule.

62–6. faucets

Valves determine the route of operation, washing and repair. Their improper arrangement can turn the service of a small piece into the drain of a large part of the collection.

Connection diameter is not the only criterion for valve selection. Pressure, temperature, material of components in contact with fluid and pressure drop curve should also be checked.

A multi-way valve should be selected for the same filter arrangement. For example, Pentair introduces different valve models for specific filter families; Similarity of connection does not mean substitutability. Pentair multi-way valves ^[437]

For manual valves, filter redirection, pump stop and changeover procedure must be done according to the manufacturer's instructions. Before opening the tank or cap, it is necessary to safely shut down, isolate and depressurize.

All taps must have an ID. The valve status table should be installed next to the system in "cleaning", "washing", "flushing" and "repair" modes.

62–7. The smooth ones

62-7-1. The difference between smoothness and filter

A strainer is usually used to prevent larger objects from entering the pump or sensitive equipment. The suction strainer does not take the place of the main filtration filter, and it should not be too dense without a hydraulic check to remove fine particles.

Strainers can be designed in the form of a basket, line or entrance protector. The selection should be compatible with the flow rate, possible object size, cleaning space and pressure drop.

62-7-2. Free level crossing

The speed of passing through the apertures is obtained from the following relationship:

$v=\frac{Q}{A_{free}}$

$A_{free}$ is the real free surface of the apertures; Not the apparent area of ​​the sheet or flat body.

For example, if the apparent area is $0.20m^2$ and the assumed share of open space is 40%:

$A_{free}=0.08m^2$

Constipation reduces this level. For this reason, the calculation should also take into account the state of soiling and the cleaning schedule.

62-7-3. Filters introduced by GSO

In introducing the suction basket strainer family, GSO has announced the 304 stainless steel material, gear connection, connection range from 2 to 6 inches and strainer surface range from 0.12 to 0.55 square meters. On the same page, two-, three-, and four-inch models are listed as 610, 611, and 612. GSO suction basket strainer ^[438]

For practical selection, orifice size, effective free surface, pressure drop in design flow rate and required space for opening should be determined. Also, the normal strainer should not be considered as a suction safety cover in the space accessible to people without evaluation.

62–8. Consumable parts

62-8-1. List of consumables and spare parts

All these items do not have the same replacement period. Some are replaced based on working hours, some based on performance quality, and some according to expiration date or manufacturer's instructions.

62-8-2. Inventory management

For each item, the compatible equipment code, part code, installed quantity, supply time and minimum stock should be recorded.

A simple way to schedule an order:

$\mathrm{نقطه\; سفارش}=\mathrm{مصرف\; مورد\; انتظار\; در\; زمان\; تأمین}+\mathrm{ذخیره\; اطمینان}$

For a component whose failure would stop the entire treatment system, lead time is usually more important than unit price. On the other hand, storing more chemicals and reagents with expiration dates can lead to waste.

62-8-3. Record performance and maintenance

The operation form should allow comparing the current state with the delivery state:

In an interactive fountain, pre-opening inspection, water quality testing and recording of actions should be part of the daily schedule. The distance of the tests and the permissible limits are determined based on the approved instructions of the project. CDC Operation and Monitoring Guide

62–9. Documents required to deliver the system

The delivery of treatment equipment is complete when the operator can start, control and service them. Delivery documents must include the following:

1. The final map of the circuit and the identification of equipment and valves; 2. Basis for calculating the volume, flow rate and treatment capacity; 3. Pump curve and filter and media technical information; 4. Instructions for washing and waste disposal route; 5. Water quality management plan and conditions for stopping and reopening; 6. Safety information sheets of consumables; 7. List of consumables and spare parts with order code; 8. Measurement results during start-up and protection performance test; 9. User training and responsibilities program.

In the delivery test, in addition to observing the operation, the actual flow rate, initial pressure difference, washing performance, leakage, and the system's reaction to the interruption of flow should be checked and recorded.

62–10. Suggested images for layout

In the schematic illustration, the direction of flow and arrangement of the equipment must be consistent with the approved project plan. The photo of the actual product should also be included with the model name and archive source so that the training image is not confused with the product that can be ordered.