Dead Weight Hatches Model A, AL

The Model A is a dead weight pressure relief gauge and thief hatch with round 8″ nominal diameter API base. The Model A also provides vacuum relief capacity.

The Model A-L is a dead weight pressure vacuum relief gauge and thief hatch with (8″x18″) oblong API base.

Technical Data

Sesco SKU:tp-024 Category: Brand:

Available on backorder


When excessive pressure builds within the storage tank the vent’s hinged cover begins to open at the predetermined set pressure, relieving excess pressure.

When the over pressure has dissipated the cover reseats onto the base. The hinge mechanism prevents misalignment and provides an accurate reseat.

When excessive vacuum builds within the storage tank the spring loaded pallet lifts, breaking the seal between the seat and pallet, allowing vapors to pass through the valve orifice relieving the vacuum buildup. The vacuum valve reseals upon relief and remains sealed.


Features & Benefits

  • Full opening lid design for higher venting capacity requirements
  • Field replaceable gaskets without the need of special tools or complex procedures
  • Optional gasket materials available for “Sour Gas” or corrosive applications
  • Non-Corrosive coating option for extremely harsh environments
  • Certified flow capacities in accordance with API


Model A Dimensions and Parts


Ref.Part No.Part NameMaterialQty.
11 1BaseAluminum1
2A101-2CapCast Iron1
3A102-2Center 0.06 kgCast Aluminum1
0.06, 0.11 kg
Cast Iron1
4A103Vacuum DiscCast Aluminum1
5A104Vacuum GasketBuna N1
*5A104VVacuum GasketViton1
6A105Vacuum Disc SpringStainless Steel1
7A106Cotter KeyPlated1
8A107Cap Set ScrewPlated1
1010GPressure GasketSp. Neop.1
*10110-GVPressure GasketSponge Viton1
115-KHinge PinCRS Plated1
12HPC-148Hinge Pin ClipPlated1
*13110-BGBase GasketTank Packing1
*141/2-13×1 1/2Bolt, HexPltd.16
*141/2-13Nut, HexPltd.16

* Optional – Furnished upon request only.

Model A-L Dimensions and Parts

model a-l dimensions

Ref.Part No.Part NameMaterialQty.
2A111CapCast Iron1
3A112Center 0.06 kgCast Iron1
*3A114Center 0.11 kgCast Iron1
4A103Vacuum DiscCast Aluminum1
5A104Vaccum GasketBuna N1
*5A104VVacuum GasketViton1
6A105Vac. Disc SpringS.S1
7A106Cotter KeyPltd.1
8A107Cap Set ScrewPltd.1
1010GPressure GasketSp.Neop.1
*1010GVPressure GasketSponge Viton1
115Hinge PinCRS Plated1
12HPC-148Hinge Pin ClipPltd.2
*13AL-BGBase GasketTank Packing1
*141/2-13×1 1/2Bolt, HexPltd.26
*141/2-13Nut, HexPltd.26

* Optional – Furnished upon request only.