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Aeration and air-bleed valve Type BEV

In order to achieve optimal de-aeration of the pressurised pipe system with STRATE aeration valves the valves are designed to operate at the system operating pressure. The valve size and type is determined not by the nominal size of the pressure pipe system but by the maximum flow-rate in the system. The design of the first stage is determined by the maximum output of the pump during the filling of the pipe system. This means the first stage of the valve must be able to remove as much air as the water entering the system in the maximum possible case during start-up. Should the pumping rate exceed the valve's ability to remove air the first stage of the valve will close prematurely due to the high flow-rate of air through the valve. The first bleed stage is, there-fore, a coarse ventilation stage which allows rapid filling of the system, that is to say, a rapid reduction in the included air on starting the pump. The process is reversed when the pump is switched off to allow a rapid aeration of the pipe sys-tem. The second stage has the function of bleeding air and gas that collects in the high point of the system during pump operation under system pressure. To achieve this the float weight and the bleed-jet cross-section must match the operating pressure in the valve. If adjusted for to low a pressure the valve will not allow the escape of air during pressurised operation, but only when the pump is switched off and the pressure is reduced. If adjusted for to high a pressure the valve operates only with reduced amounts of bleed air which can lead to problems in operation. Satisfactory operation can no longer be guaranteed under these circumstances. Adjustment of the valve to match opera-ting conditions only concerns the internal components of the valve as the housing and flange connection to the system are matched to the pressure rating of the system only. For STRATE BEV valve housings there are the following pressure ratings.

  1. Series valves according to rule with max. 6 bar operating pressure at installation point. Standard housing in GGG 40. Housing pressure tested to max. 10 bar. Flange connection to PN 10.
  2. Special valves with deviating dimensions with max. 10 bar operating pressure at installation point. Special housing in RSt 37.2 of welded construction. Housing pressure tested to max. 16 bar. Flange connection to PN 10.
  3. Special valves with deviating dimensions with max. 16 bar operating pressure at installation point. Special housing in RSt 37.2 of welded construction. Housing pressure tested to max. 25 bar. Flange connection to PN 16.

As the majority of pressure pipe systems seldom reach a head of 60 mwc the standard valve with a rating of 6 bars sufficient under most circum-stances. In long pipe systems the pressure at the point of installation is reduced the further installation is from the pump. In order to guarantee suitable functioning of the valve it is necessary to supply us with all the information about the pipe system and the pump station.

Aeration and air-bleed valves BEV- G AND BEV- F   Single stage valves DBP No. 431803  

STRATE BEV- G

(Coarse ventilation)

The STRATE BEV- G is a single-stage valve which functions as per the first stage (coarse ventilation).  For the installation of the valve the same conditions apply as described above for the first stage of the to stage valve. Adjustment to match the operating pressure is not necessary for the first ventilation stage as the coarse ventilation stage remains closed when under pressure.

Special applications for this valve are:

  1. Aeration of individual falling sections of pipe.
  2. Quick air bleeding of high points where fine ventilation is not appropriate (e.g. short pump run times)
  3. Vacuum protection in long falling or rising sections.

 

STRATE BEV- F

(Fine ventilation)

The STRATE BEV- F is a single-stage valve which functions as per the second stage (fine ventilation) described above. For installation of this valve the same conditions apply as described above for the second stage of the two-stage valve.

Special applications for this valve are:

  1. High points which due to the high head of the system remain under hydrostatic pressure even when the pump isn't operating and for which a coarse valve would not therefore be appropriate.
  2. High points of systems where the flow-rate is limited. (Flow-rate may not exceed the maximum bleed-rate)

Materials:

Housing: GGG 40

Float: Plastic NCPE

Nozzle and valve face: Stainless steel1.4571

Screws: Steel zinc coated

Corrosion proofing: EGD coating

Colour tone: Green DB 601

 

Click here for BEV Dimensions