Respiratory valves

Safety valve hydraulic CNG

A water lock to protect the tank from excessive overpressure and vacuum. It works in conjunction with the breathing valves NDKM, KDM and KDS.

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Safety valve hydraulic CNG
Description

Purpose and design

CNG insures the tank when the mechanical breathing valves fail. The principle is a hydraulic gate: liquid is filled in the valve cup, and as long as the pressure is normal, it blocks the passage. As the pressure increases, the liquid level decreases, reaches the lower end of the nozzle and is ejected onto the screen, after which the gas space communicates with the atmosphere. Under vacuum, the shutter works in the opposite direction: air penetrates through the recesses of the teeth of the partition.

It consists of a housing with a connecting pipe, a liquid cup, a holder with a submerged pipe, a screen against liquid entrainment, a fire fuse, a lid against precipitation and a drain-filling tube. A low—freezing, slightly evaporating liquid is poured, the level is monitored with a dipstick - this is the main regular operation for valve maintenance.

Parameters

Technical specifications

TypeHydraulic safety valve
PurposeProtection of the tank from excessive increase of excess and vacuum pressure
Working in a bundleTogether with breathing valves NDKM, KDM, KDS
The principle of operationHydraulic shutter with liquid ejection onto the screen
CompositionHousing, water lock cup, clip with submerged nozzle, shield, safety catch, lid, drain-filling tube
MaterialThe body is carbon steel, the fire—blocking element is aluminum alloy, stainless steel on request
Installation locationMounting pipe on the tank roof
Climatic versionY, XL or UHL, placement category 1 for ГОСТ 15150-69
Models

Size range

Standard sizeDN, mmThroughput capacity, m3/h, not lessL, mmB, mmH, mmD/D1/d/nWeight, kg, max
КПГ-100100200764600945205/170/18/470
КПГ-1501505009627931250260/225/18/886
КПГ-200200900———315/280/18/886
КПГ-2502501500107810781278370/335/18/1293
КПГ-3503502700116910001373485/445/22/12210

The operating pressure is 1764-1961 Pa (176-196 mm of water), the vacuum is 343-392 Pa (34-39 mm of water) — the same for the entire range. The service life is 10 years, followed by replacement or periodic testing.

Documentation

Drawings

Drawing — Safety valve hydraulic CNG
General view
Questions

Frequently asked questions

Why use a hydraulic valve if there is a mechanical breathing valve?
The mechanical one works constantly and keeps the pressure within the operating limits. CNG comes into operation when it is missing or has failed, and prevents the tank from collapsing. They complement each other.
How should I fill the water lock and how often should I check the level?
A low-freezing, slightly evaporating liquid. The level is monitored by a probe and is included in regular maintenance: when it falls, the valve loses its tightness and begins to leak vapors.
How to choose a standard size?
According to the required bandwidth: range from КПГ-100 at 200 m3/h to КПГ-350 at 2700 m3/h. Name the volume of the tank and the capacity of filling and pumping — we will select it.
What happens after it is triggered?
A part of the water seal liquid is ejected onto the screen. After the pressure is normalized, the level must be checked and refueled if necessary, otherwise the next trigger will not be at the calculated values.

Do you need a CNG valve?

State the size and parameters, or send a specification — we will make the selection and prepare a quotation.

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