General Description

Model 264DD, 264HD and 264ND detailed in this data sheet apply for those

transmitters which include on high pressure measuring side, a direct mount

seal which is integral to the transducer by a short capillary connection inside

a protective rigid tube. This construction forms a standalone single assembly

suitable to be mounted to the process by the seal mounting facilities.

By properly selecting the high and low pressure side variant in the ordering

codes model 264DD can be in the following versions :

a) one direct mount seal and one flange for process connection, direct

1/4 – 18 NPT or 1/2 – 14 NPT through adapter; this allows also to connect

the other leg (wet or dry) for differential measurement.

A proper filter is supplied as standard  when 1/4 – 18 NPT connection is

selected, in order to plug the unused entry, leaving it vented for gauge

measurement with reference to atmosphere.

b) one direct mount seal and one remote seal with capillary; the two seals

allow again a differential measurement and must be selected of same

type/size.

Model 264HD and 264ND have the direct mount seal on the positive side,

respectively with the reference at atmospheric or vacuum pressure, for

gauge or absolute measurements.

Allowed types of direct mount seal are mainly used for chemical application:

– flush diaphragm flange mounted seal

-extended diaphragm flange mounted seal-off

-line threaded connection sea

-off-line flanged connection seal

These are suitable also for other process applications including food and

sanitary, using FDA approved filling, which are defined as food fills and are

Generally Recognized As Safe (GRAS) by the US Food and Drug Administration

(FDA). Refer to seal data  sheet for all data and details relevant to seal

element. The following table list the types of standard seal which can be

mounted with 264DD, 264HD and 264ND transmitters (the mnemonic is

used as reference in the compatibility table).