Softening / Water Softeners From Hungerford & Terry
- There is no graded gravel bed to buy, transport, handle at the job site, and install.
- With most types of H&T gravelless units, there is no concrete fill to buy and install in the bottom of the filter below the strainers.
- The tank height is lower which means a saving in tank cost and its delivery cost, and the tank is easier to handle at the job site during installation. The lower tank height permits its use in a lower height room or building.
- The space in the bottom of the unit previously used for a gravel supporting bed may be used for a greatly increased bed depth of filter media or zeolite, thus providing a greater flow rate and/or softener quality.
- Rugged, corrosion-resistant, stainless steel strainers, uniformly spaced, extend completely across the entire tank bottom and provide better collection of the treated water and more uniform distribution of the backwash water. Strainers may be factory-installed, if desired ... at a small additional cost.
- Units have an extremely low head loss, even when equipped with greater bed depths of filter media and operated at a greater flow rate.
- A lower overall installed equipment cost. This construction is also applicable to overhauling, rebuilding, and modernizing old, low height filters and softeners.
H&T water treating units of the gravelless type offer a number of important features to be considered today by discriminating buyers of water conditioning systems.
H&T gravelless designs are used for both closed pressure type units and open gravity-type units, either manually or automatically operated as preferred. They cover a wide class range including softeners, H&T sand and anthracite filters, Neutralex filters, Acticar filters, and Ferrosand "CR" filters.
Natural Water
Hard water is a problem in a wide range of industries. Since nature seldom supplies pure water, an industry's water source, whether municipally supplied or from ground water, contains calcium and magnesium, which can create additional processing costs or adversely affect final product quality if these unwanted minerals are not eliminated.
Softening Process
Water is softened by removing the hardness-producing ions, or specifically, the cations of calcium and magnesium. In the ion exchange reaction, sodium is substituted for hardness ions. The anions, bicarbonate, chlorides, sulfates, etc., are not changed in this process.
The symbol Rz refers to the ion exchange resin which is frequently referred to as zeolite. The original zeolites or materials resembling zeolites, which include greensand or synthetic alumino silicate cation exchange materials are very seldom used today because of the more durable and higher capacity styrene-divinyl benzene type ion exchange resins.
The two basic cation exchange resins used in water softeners are the gelular and macroporous type. For normal applications or service conditions, the gel resins are most commonly used. For special cases such as high temperature or thermal shock, aggressive oxidizing conditions, or in installations in which the gel type resins have given poor service, the macroporous resin would be recommended.
- Softener Regeneration
After the resin in the softener has reached its exchange capacity, that is, becomes exhausted, hardness begins to leak or is present in the treated water. It is then necessary to regenerate the softener.
Backwash
This step removes all the suspended matter collected on the previous service run and loosens and classifies the resin bed by allowing the backwash water to flow upwards through the bed and out to waste for a minimum period of 10 min. or until the waste is relatively clear. The flow rate is usually in the 5-7 gpm./sq. ft. range or sufficient to produce a minimum resin bed expansion of 50%.
Brine Injection
In order to remove the calcium and magnesium from the ion exchange resin, a predetermined quantity of 10% brine is passed through the resin at a sufficient rate to provide a 15-20 min. contact period.
Slow Rinse
This step is usually accomplished by stopping the flow of saturated brine and using the dilution water only to flush out the bulk of the brine. This step in essence provides another 10-15 min. brine contact time, which allows the remaining brine to contact the resin efficiently.
Fast Rinse
The fast rinse removes the last traces of calcium, magnesium, and excess sodium chloride from the resin. The fast rinse rate is usually between 1 and 2 gpm./cu. ft.
Softener, Countercurrent Regeneration
The above steps are described for the conventional downflow type brine regeneration and service. In some instances where regeneration efficiency and soft water quality are important, the brine injection and slow rinse is admitted to the bottom of the softener and flows upwardly through the compacted ion exchange resin bed. This allows the bottom of the resin bed, which is the last portion the service water contacts, to be most fully regenerated and results in the lowest possible hardness leakage at nominal regeneration levels.
A nest of automatically operated individual valves is usually lowest in first cost for larger size (66" dia. or more) installations. Method of valve actuation can be pneumatic, hydraulic, or electric, depending upon your preference and the type of valves selected.
The rotary disc type multiport valve is usually lowest in cost for smaller size (60" dia. or less) installations. The valve is hydraulically operated (it requires a minimum of 25 psi to operate), electrically controlled, and has a maximum pressure limit of 100 psi.
For best all around operating service, an automatic H&T poppet type multiport valve should be your choice. Though not the least expensive choice, it is a masterpiece of workmanship and operating simplicity and has no equal in the multiport valve field. They are available in 2-1/2", 4", and 6" sizes, to cover the entire range of softeners.
Softener Tank
H&T softener tanks are built of welded steel plate, usually in accordance with section VIII of the ASME code. However, non-code construction is available where its use is allowed. Softener tanks are normally furnished unlined, with adjustable jackleg supports, a 12" X 16" manhole, and prime painting. However, tank linings, structural steel supports, larger manholes and special painting can be furnished to meet any unusual requirements.
Internal Distributors
The underdrain system in the bottom of an H&T softener can be of (1) the header-lateral type with drilled red brass laterals, (2) a header-lateral type with brass or stainless steel nozzles spaced at regular intervals on the laterals, (3) a hub-radial lateral type of plastic construction, or (4) which features stainless steel containers covered by 3/16"-10 mesh fine gravel.
Underdrain types 1 & 2 require that the purchaser fill the bottom head with concrete; they also require the use of a graded gravel bed. Type 3 if the laterals are unwrapped, requires a graded gravel bed; however, if the laterals are wrapped, it requires only that the laterals be covered with fine gravel for the purpose of even distribution. Neither underdrain type 3 nor type 4 require concrete fill, and can be factory installed.
Each of the underdrain types has proven itself worthy of the H&T name through years of satisfactory service in numerous installations.
An inlet distributor/waste water collector is provided for each H&T softener. These are designed to uniformly distribute the water over the entire resin bed.
A brass header-lateral brine distribution system utilizing the H&T brine valve is the best and most efficient way of easily distributing the brine. The brine valve has four (4) horizontal discharge ports, to insure uniform distribution and minimize resin bed disturbance. A PVC header-lateral brine distribution system is available without the H&T brine valve at a lower cost.
Gravel Bed
The graded gravel bed immediately above the underdrain is provided to aid in the distribution of the wash water. The top layer of gravel, the supporting layer, supports the resin and prevents its passage out of the softener. The gravels used by H&T are carefully graded, spherically shaped, iron and lime free.
Automatic Controls
All softener control panels used for automatic and semi-automatic operation are designed, fabricated, wired and tested in our Clayton, New Jersey, plant. This work is not "farmed out" to others and, consequently, there is completely undivided responsibility.
Softeners equipped with individual valves or any of our various multiport valves can be furnished with fully automatic, semi-automatic, or any of many special types of control panels and for either single or multiple softener unit installations. Ordinarily, automatic controls make use of a contact meter head and an automatic re-set counter, which can be easily adjusted over a wide range of softener capacities although these controls can be supplied for installations requiring an adjustable alarm dial register meter with automatic re-set depending on preferences.
The semi-automatic control panel provides a push button for initiating the regeneration cycle. An alarm dial meter and alarm bell or warning light are used to signal the operator that the softener has reached the end of the softening run and requires regeneration. Then a momentary depression of the "start" push button energizes the control circuit which in turn automatically operates either the individual valving or the multiport valve supplied on the softener unit.
In the case of installations requiring special control panels, facilities are available to design, fabricate, and test them to meet any special requirements.
Meters
Softeners are equipped with disc, turbine or propeller type meters and either a standard reading register or a vertical dial register. Each meter is selected for accuracy and pressure loss at the flow range required.
Brine Tanks and Regenerating Systems
In general, water softeners are equipped with one of the three following types of brine tanks and regenerating systems, although there are many other alternate arrangements sometimes employed:
- A single fiberglass combination saturator-measuring tank with gravel bed, collecting system, transfer ejector, and necessary valving, and a float gauge for indicating the correct amount of brine. In some cases, a brine pump is used instead of the ejector for transferring the brine from saturator to the softener being regenerated. Galvanized steel, or lined steel brine tanks are also available.
- Two brine tanks connected in series, one serving as a salt saturator and the other as a brine measuring tank sized to provide enough volume of saturated brine for one regeneration of each softener unit. Each system is equipped with either an ejector or brine pump with the necessary operating valves.
- Where large quantities of salt are consumed, it may be advantageous to use a bulk salt saturator. The bulk saturator tank is sized to hold a truckload or a carload of salt.
Each water softener is equipped with pressure gauges to indicate loss of head at various flow rates and automatic backwash and brine rinse controls for use either in an open sump or closed pressure drain system. Also, each water softener is equipped with sampling cocks and a test kit complete with testing solution.