Use as an air fil­ter pres­sure gauge to mea­sure air fil­ter pres­sure drop and indi­cate when ser­vice is required

The pres­sure gauge pro­vides a visu­al indi­ca­tion of when the fil­ter needs ser­vice. Select a mod­el with a mea­sure­ment lim­it cor­re­spond­ing to the allow­able pres­sure drop across the fil­ter, as rec­om­mend­ed by the fil­ter man­u­fac­tur­er. Install a pres­sure gauge with a red point­er posi­tion indi­ca­tor (avail­able sep­a­rate­ly) set at the point of max­i­mum pres­sure drop for the vol­ume of air han­dled. This ensures that the pres­sure gauge is easy to read, even by an inex­pe­ri­enced oper­a­tor.

Mea­sure­ment of sta­t­ic pres­sure in an air stream

For the high­est accu­ra­cy in mea­sur­ing sta­t­ic pres­sures in sys­tems with air flow, con­nect a pres­sure gauge to a sta­t­ic pres­sure valve. The most accu­rate receiv­er is a smooth, razor-sharp sol­der joint “flush” with the inner sur­face of the chan­nel. A sim­ple con­nec­tion is only slight­ly infe­ri­or in accu­ra­cy.

Air flow mea­sure­ment

Con­nect a pres­sure gauge to the pitot tube in the air stream. A sim­ple alter­na­tive is the method illus­trat­ed above — a sta­t­ic valve plus a sim­ple pipe in the cen­ter of the chan­nel as a total pres­sure receiv­er. The dif­fer­en­tial pres­sure read is the veloc­i­ty pres­sure at the cen­ter, which can be con­vert­ed to air­flow veloc­i­ty.

To deter­mine the air flow rate when mea­sur­ing the flow vol­ume

An ellip­ti­cal mea­sur­ing noz­zle with an upstream air grid pro­vides an accu­rate, sim­ple design device for mea­sur­ing air vol­ume. The dis­tri­b­u­tion of air veloc­i­ties along the noz­zle at the out­let point is uni­form, the sta­t­ic pres­sure is zero. Accord­ing­ly, the total pres­sure upstream of the noz­zle is deter­mined by the veloc­i­ty head at the out­let of the noz­zles, and the flow vol­ume is eas­i­ly cal­cu­la­ble.

Check­ing the air fil­ters of engines or com­pres­sors

The pres­sure gauge pro­vides a con­tin­u­ous dis­play of the air pres­sure drop across the fil­ter and indi­cates when it needs to be cleaned or replaced. The pres­sure gauge is mount­ed on the neg­a­tive or low pres­sure port con­nect­ed to the suc­tion pipe between the fil­ter and the motor or com­pres­sor.

Air con­di­tion­ing con­trol

Adjust­ing the air­flow for sea­son­al changes may require peri­od­ic reset­ting of the set­points. The abil­i­ty of the device to mon­i­tor the pres­sure in the line also allows the col­lec­tion of data on oper­at­ing con­di­tions. If nec­es­sary, this becomes a use­ful func­tion in the face of chang­ing pres­sures and vol­umes of sys­tems.

For pres­sure mon­i­tor­ing in air-filled build­ings

The Pho­to­hel­ic® con­tact pres­sure switch/gauge sens­es an over­pres­sure that must be gen­er­at­ed in an air-filled build­ing or a lack of pres­sure that could cause it to col­lapse and con­trols the blow­er fan to pro­vide the cor­rect pres­sure. The pres­sure gauge is eas­i­ly recon­fig­ured to main­tain pres­sure or pro­vide an increase to coun­ter­act the effects of wind.

Liq­uid lev­el detec­tion

By mea­sur­ing the back pres­sure of the purge air in a deeply buried pipe. Gauges can be used in con­junc­tion with a flow meter with a con­stant dif­fer­en­tial pres­sure reg­u­la­tor as shown. The flow meter pro­vides a con­stant amount of purge air to the dip tube. Flu­id lev­el changes affect the head, caus­ing a change in the sta­t­ic pres­sure inside the pipe. These changes are rec­og­nized by the manome­ter. The same set­up allows you to deter­mine changes in the grav­i­ty of the liq­uid while main­tain­ing its lev­el con­stant. The use of a con­tact pres­sure trans­duc­er instead of a pres­sure gauge pro­vides both mea­sure­ment and con­trol of the liq­uid lev­el and ease of chang­ing set­points.

As a diaphragm sen­sor

Gauges can be used as a diaphragm gauge when purg­ing the diaphragm with pres­sur­ized air to pro­tect the gauge from direct con­tact with liq­uid or to pre­vent clog­ging of the mea­sur­ing lines. The illus­tra­tion shows a pres­sure gauge con­nect­ed to two flowme­ters with con­stant dif­fer­en­tial pres­sure reg­u­la­tors, one on the low pres­sure side of the valve and one on the high pres­sure cir­cuit. (With a com­pat­i­ble flu­id flow indi­ca­tor, the gauge can be used with­out purg­ing.)

Mate­r­i­al weight con­trol

In paper machines or weav­ing machines, a con­tact pres­sure transducer/gauge con­trols the weight of the mate­r­i­al being fed accord­ing to changes in pres­sure caused by changes in its per­me­abil­i­ty or thick­ness of the mate­r­i­al.

For life sup­port machines or arti­fi­cial kid­ney

The Pho­to­hel­ic® con­tact pres­sure transducer/gauge mon­i­tors the cir­cu­la­tion pres­sure in life sup­port sys­tems and devices and pro­vides warn­ings of increas­es and decreas­es in pres­sure beyond set lim­its.

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