VRV-100 Vaccum Relief Valve

Pressure / vacuum relief valves or breather valves are special types of relief valves which are specifically designed for tank protection. The range includes pressure only, vacuum only and combined pressure / vacuum valves, all available with flanged outlets or vented to atmosphere Pressure / vacuum relief valves are used extensively on bulk storage tanks, including fixed roof tanks with floating covers, to minimize evaporation loss. The valves prevent the buildup of excessive pressure or vacuum which can unbalance the system or damage the storage vessel.

The range includes pressure only, vacuum only and combined Pressure/Vacuum Valves, all available with flanged outlets or vented to atmosphere. Pressure/Vacuum Relief Valves are used extensively on bulk storage tanks, including fixed roof tanks with floating covers, to minimize evaporation loss. Pressure/vacuum relief valves prevent emission losses until very close to the set pressure, and prevents air intake until very close to the set vacuum. The geometry of the valves has been developed in order to optimize overall performance in terms of high flow capacity, set pressure, sealing and re-sealing.

The Vacuum Relief Valve is an advanced design for vent to atmosphere applications. Utilizing the latest technologies, this relief valve provides protection against negative or positive pressure, prevents air intake, evaporative loss of product and helps contain odorous and potentially hazardous vapors.

The Vacuum relief valve is designed to be installed on pressurized tanks static or transportation application. The vacuum relief valves prevent the unallowable entrance of air up to the adjusted set pressure and offer reliable protection against vacuum.

Operation
Teleflo makes vacuum relief valves (VRV) in various metallic materials, with a wide variety of elastomeric seat seals. There are several sizes available, as well as pressure settings. The purchaser must exercise care to select the most desirable combination of features for the intended service conditions.

Since the VRVs are frequently small in size, and are set at very low pressures, these valves cannot withstand much abuse. Although the valve’s sole purpose is to permit air from the atmosphere to be introduced into the tank when a negative pressure (of a prescribed amount) occurs in the tank, it has been used wrongly on occasions to ascertain if positive pressure exists in the tank. As an example, an operator may push the stem down by stepping on it to see if there is pressure in the tank before opening up the man way cover. A likely result of this is to damage the valve by bending the stem, as well as releasing product that could harm the operator.

We would supply weather cover for VRV additionally if client requested. This part helps keep rain, cinders and other debris from accumulating in the inside of the valve body, which when the valve opens, will then potentially drop into the tank. A weather cover also serves as a deflector when there is flow out of the VRV to protect personnel near the valve. the threads to facilitate getting a good pressure-tight seal.

Do not use a large pipe wrench to install the threaded valve. Care should be taken not to distort the valve body’s internal seat.

Remove the fasteners using suitable tools. Note: All work on the valve should be performed by a skilled mechanic with proper tools.

Maintenance
The seal that makes the VRV bubble tight is the resilient seal. Do not try to lap the metal to metal seats between the stem and valve body.

The metallic seats on the stem and the valve body are carefully machined at an angle. Do not attempt to reaching them. However, removing rust, solidified product, and other debris by hand, or with emery paper is desirable.

The resilient seal of valves are almost always round shaped pressure seals. Replacement pressure seals of whatever material is required should be purchased only from Teleflo.

VALVE TESTING PROCEDURE
Mount the valve on the test stand using proper tools with skilled person.

Test the vacuum test three times to verify proper operation. Record all test vacuum readings on the Shop Data Sheet.

With the valve mounted on the test stand, slowly increase the vacuum pressure while monitoring the air supply pressure flow rate. For vacuum tests, the block valve is opened sufficiently to allow a steady increase in vacuum condition. To adjust the adjustment screw as the setting is approached, continue to open the valve.

The set (vacuum) will be the point at which the test pressure (vacuum) does not increase with a corresponding increase in flow rate. Normally, at this point, the test pressure (vacuum) will fluctuate up and down as the valve relieves, while the flow rate remains steady. The set vacuum is the maximum vacuum achieved during the test.

Repeat this test two more times to achieve a total of three measurements of set pressure and vacuum.

The acceptable tolerance range for set (vacuum) is +/- 10%. All three test results must fall within the specified tolerances for the vacuum settings listed on the sales order. Record the three set vacuum measurements on the Shop Data Sheet