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- Uses and advantages of the Volumetric dosing systems<\/span><\/dt>\n
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The mixer unit is proposed as alternative to the traditional mixing systems, such as Venturi systems, membrane tanks, variable flow systems.<\/p>\nThe possibility of drawing up foaming liquid from any type of atmospheric stockage, without interruptions or any particular operations of re-filling during the emergency phase.<\/p>\n
The machine is in fact able to draw up the foaming liquid even in negative inlet pressure.<\/p>\n
Therefore pressure tanks, necessary in membrane type units, and also the pressurisation systems with pumps and distribution networks, necessary in pressure control units, are eliminated.<\/p>\n
The advantage is evident in terms of cost, space and, above all, in the operability of the system.<\/p>\n
With this equipment it is just necessary to install a minimum amount of foam liquid stock on site for the initial intervention and then refill the tank by means of connection with mobile vehicles, drums or containers.<\/p>\n
There is a drastic reduction in the possibility of breakdown and maintenance; the total absence of a membrane for the separation of water\/foaming liquid, calibrated diaphragms or regulating valves, together with the constructive simplicity and the choice of materials, reduce to the minimum the possibility of breakdown and maintenance work.<\/p>\n
The membrane proportioner needs complicated maintenance operations (use of crane for lifting etc.) for the membrane removal. All these operations are no longer needed, saving money and time.<\/p>\n
Simplicity in operation: the unit does not need any activation operation apart from the opening of the delivery valve of the foaming solution to the various utilities.<\/p>\n
The system can adjust itself automatically to the required flow-rate.<\/p>\n
Since the versatility in the injection capacity is independent to the up- and downstream pressure capacity of the unit, the proper modifications to get really needed output can be easily made.<\/p>\n
It is possible to develop a foam mixing distribution network connecting several parallel mixing units; in this way, each unit’s flow-rate can be added to the others’ until reaching the required total flow-rate.<\/p>\n
This type of application is ideal for fires in large scale plants due to the fact that foam mixture is available in all zones of the plant, and, as it is possible to activate
\nonly the premixing units further away from the fire front, a continuous re-filling of foam solution by vehicles which can work at safe distances, is guaranteed.<\/p>\nEasy execution of periodical tests, since it is possible to re-cycle the foaming liquid in the tank without mistakes in handling and avoiding waste of product.<\/p>\n
Versatility in mixing any kind of foam liquid, since the machine is calibrated for a mixing percentage fixed beforehand.<\/p><\/div>\n<\/dd>\n
- Comparative table for premixing units<\/span><\/dt>\n
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\n\n\n
\n <\/p>\n WORKING CONDITIONS<\/p>\n
<\/td>\n
\n<\/span><\/b><\/p>\nBLADDER TANK PREMIXER<\/span><\/b><\/p>\n<\/td>\n
\n<\/span><\/b><\/p>\nVARIABLE FLOW RATE SYSTEM<\/span><\/b><\/p>\n<\/td>\n
\n<\/span><\/b><\/p>\nVOLUMETRIC SYSTEMS<\/span><\/b><\/p>\n<\/td>\n<\/tr>\n
\n
\n<\/span>1) Working Principles<\/span><\/td>\n
\n<\/span>Venturimeter + Calibrated orifice disk<\/span><\/td>\n
\n<\/span>Dosage according to pressure & flow rate (Venturi)<\/span><\/td>\n
\n<\/span>Volumetric ratio water\/foaming liquid<\/span><\/td>\n<\/tr>\n\n
\n<\/span>2) External energy sources<\/span><\/td>\n
\n<\/span>Water under pressure<\/span><\/td>\n
\n<\/span>Water under pressure Foam under pressure<\/span><\/td>\n
\n<\/span>Water under pressure<\/span><\/td>\n<\/tr>\n\n
\n<\/span>3) External elements required for operation<\/span><\/td>\n
\n<\/span>None<\/span><\/td>\n
\n<\/span>Foam pumping units (electrical and\/or diesel pumps) and distribution network<\/span><\/td>\n
\n<\/span>None<\/span><\/td>\n<\/tr>\n\n
\n<\/span>4) Type of foam stock<\/span><\/td>\n
\n<\/span>Local in pressure tanks with separator membrane<\/span><\/td>\n
\n<\/span>Distribution network<\/span><\/td>\n
\n<\/span>Local in any atmospheric container<\/span><\/td>\n<\/tr>\n\n 5) Required conditions for mixing <\/span> <\/span><\/td>\n
\n<\/span>Pressurisation of foaming liquid storage tank<\/span><\/td>\n
\n<\/span>Foam feeding network pressurisation<\/span><\/td>\n
\n<\/span>None. Complete autonomy in operation<\/span><\/td>\n<\/tr>\n\n
\n<\/span>6) Intervention autonomy<\/span><\/td>\n
\n<\/span>Limited by the capacity of the storage tank and drainage operation complexity<\/span><\/td>\n
\n<\/span>Limited by the capacity of centralised storage tank, which can anyway be refilled by vehicles<\/span><\/td>\n
\n<\/span>Unlimited. It can draw up foam in any conditions, also by negative inlet pressure<\/span><\/td>\n<\/tr>\n\n
\n<\/span>7) Reintegration of foaming liquid<\/span><\/td>\n
\n<\/span>Possible by doubling the storage tank in pressure. Otherwise it is necessary to stop foam output.
\nComplex operation requiring personnel in critical areas<\/span><\/td>\n
\n<\/span>Possible by transferring foaming liquid from vehicles to storage tank<\/span><\/td>\n
\n<\/span>Unlimited until foaming liquid stock is finished.
\nNo interruption in foam output.
\nFoam reintegration by gravity<\/span><\/td>\n<\/tr>\n\n
\n<\/span>8) Foam concentrate refilling<\/span><\/td>\n
\n<\/span>Very complicated: one of the 2 tanks must be isolated, and water drained by removing it with the same amount of foaming liquid.
\nOperations made in critical phases.<\/span><\/td>\n
\n<\/span>Simple: Normal operations of foaming liquid transfer in security zones.<\/span><\/td>\n
\n<\/span>Simple: Normal operations of liquid transfer carried out at safety distance by means of mobile connections.<\/span><\/td>\n<\/tr>\n\n
\n<\/span>9) Variations field of foam distributions flow-rate<\/span><\/td>\nTheoretically 10:1;
\nGenerally, the calibration curves are not available <\/td>\n
\n<\/span>Theoretically 10:1;
\nGenerally, calibration curves are not available<\/span><\/td>\n
\n<\/span>From a minimum of 50 m^3\/h to maximum 1000 m ^3\/h obtained with single units<\/span><\/td>\n<\/tr>\n\n 10) Mixing % shifting from nominal value upon variation of flow-rate<\/span><\/td>\n
\n<\/span>Operative tests have shown high shifts from nominal values. Foam gives worse performance and by a greater consumption intervention time is shorter<\/span><\/td>\n<\/td>\n
\n<\/span>Differences in the nominal values are negligible and mixing is constant.
\nCalibration curves are available<\/span><\/td>\n<\/tr>\n\n
\n<\/span>11) Total pressure loss<\/span><\/td>\n
\n<\/span>Not always calibration curves referring to variation of flow rate (min.\/max.) are available.
\nWorking tests have shown high pressure loss values during the max. flow rate<\/span><\/td>\n
\n<\/span>There are not always calibration curves<\/span><\/td>\n
\nPressure loss is very low.
\nAccurate calibration curves are available <\/td>\n<\/tr>\n\n
\n<\/span>12) Variation field of % nominal value<\/span><\/td>\n
\n<\/span>Complex. Only possible by using a throttle device on feed-line. Effect only theoretic as precision is very low<\/span><\/td>\n
\n<\/span>Only possible with throttle on feed-line effect theoretical as precision is low<\/span><\/td>\n
\n<\/span>Effective control of % as function is based on ratio of volumes<\/span><\/td>\n<\/tr>\n\n
\n<\/span>13) Starting-up operations<\/span><\/td>\n
\n<\/span>Complex. Controls and membrane venting operation necessary<\/span><\/td>\n
\n<\/span>Complex. Filling lines, venting, calibrating recycle valves, startup pumps<\/span><\/td>\n
\n<\/span>No particular operations<\/span><\/td>\n<\/tr>\n\n
\n<\/span>14) Maintenance operations<\/span><\/td>\n
\n<\/span>Complex. Removal of membrane needs several people and cranes.
\nWater & foaming liquid must be drained<\/span><\/td>\n
\n<\/span>Membrane substitution needs specialised workers & accurate calibration of dosage valve<\/span><\/td>\n
\n<\/span>No maintenance or calibration. Materials used & construction exclude need for maintenance<\/span><\/td>\n<\/tr>\n\n
\n<\/span>15) Movement error<\/span><\/td>\n
\n<\/span>Possible during refilling operations due to the number of valves and to
\nthe movement sequence<\/span><\/td>\n
\n<\/span>Possible in pumping station<\/span><\/td>\n
\n<\/span>Practically none due to autonomy of machine<\/span><\/td>\n<\/tr>\n\n
\n<\/span>16) Hot areas: Countries or regions where summer temperatures exceed 40\u00baC<\/span><\/td>\n
\n<\/span>Temperature could melt compound protecting membrane joints;
\nfoaming liquid is therefore going inside the membrane itself<\/span><\/td>\n
\n<\/span>No contraindications<\/span><\/td>\n
\n<\/span>No contraindications<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/dd>\n<\/dl>\n<\/div>\n![](\"\/imgs\/large-seperator.png\")
<\/div>\nFiredos<\/a><\/h2>\n
General features<\/h3>\n
Technical datasheets<\/h3>\n
FD1000<\/a> – FD2000<\/a> – FD3000<\/a> – FD4000<\/a> – FD6000<\/a> – FD8000<\/a> – FD10000<\/a> – FD15000<\/a> – FD20000<\/a> – FD25000<\/a>
\n<\/p>\nImage gallery<\/h3>\n
Reference list 2010<\/h3>\n
<\/div>\n\n<\/div>\n\n<\/div>\n<\/p>","protected":false},"excerpt":{"rendered":"
General Aspects Uses and advantages of the Volumetric dosing systems The mixer unit is proposed as alternative to the traditional mixing systems, such as Venturi systems, membrane tanks, variable flow systems. The possibility of drawing up foaming liquid from any type of atmospheric stockage, without interruptions or any particular operations of re-filling during the emergency […]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":1359,"menu_order":3,"comment_status":"closed","ping_status":"closed","template":"","meta":[],"_links":{"self":[{"href":"https:\/\/www.sabo-esp.com\/en\/wp-json\/wp\/v2\/pages\/2050"}],"collection":[{"href":"https:\/\/www.sabo-esp.com\/en\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.sabo-esp.com\/en\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.sabo-esp.com\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.sabo-esp.com\/en\/wp-json\/wp\/v2\/comments?post=2050"}],"version-history":[{"count":43,"href":"https:\/\/www.sabo-esp.com\/en\/wp-json\/wp\/v2\/pages\/2050\/revisions"}],"predecessor-version":[{"id":5826,"href":"https:\/\/www.sabo-esp.com\/en\/wp-json\/wp\/v2\/pages\/2050\/revisions\/5826"}],"up":[{"embeddable":true,"href":"https:\/\/www.sabo-esp.com\/en\/wp-json\/wp\/v2\/pages\/1359"}],"wp:attachment":[{"href":"https:\/\/www.sabo-esp.com\/en\/wp-json\/wp\/v2\/media?parent=2050"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
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